Article: 97901 of rec.radio.amateur.homebrew From: "hamguy1" Subject: looking for 2 metre mobile radio Date: Fri, 7 Jul 2006 17:06:41 +1000 Message-ID: <44ae07f7$1$21440$afc38c87@news.optusnet.com.au> hi there newgroups, i live in australia im looking for either a yaesu kenwood icom or similar 2 metre for my mobile with dtmf mic preferably if anyone in the usa etc has 1 i would pay shipping to australia .thanks in advance david nsw australia . Article: 97902 of rec.radio.amateur.homebrew From: David Subject: Confused with BF998 Message-ID: <6Yorg.900$tE5.231@news-server.bigpond.net.au> Date: Fri, 07 Jul 2006 08:29:54 GMT I am going around in circles attempting to understand the datsheet for the BF998 Dual Gate FET. From what I can gather, with Vcc = 8V and 4V on G1 and ID of 10mA, at 150 MHz Input appears to be 1700 Ohms with 2.1pF par Output appears to be 1250 Ohms with 1pF par (I thought Fets had hundreds of K ohm input impedance - or is this only at low Freq ?) The typology I have is. L/C tuned circuit to G1 100K+100K providing 4V to G2 (with 100n Bypass cap close to gate) The source has 100R with 100n Par to ground. The Drain has the Inductor of the tuned circuit to Vcc (and bypassing on Vcc side as well as 47R series resistor for additional decoupling). The tuning cap goes from Drain to ground. I have about 250mV on the source (only 2.5mV bias current). How do I obtain 10mA drain current ? Or are they only referring to AC current ? Would someone mind please giving me a bit of overview of these devices. Thanks in advance Regards David Article: 97903 of rec.radio.amateur.homebrew From: "Leon" Subject: Re: Confused with BF998 Date: 7 Jul 2006 02:37:34 -0700 Message-ID: <1152265054.713381.59030@k73g2000cwa.googlegroups.com> References: <6Yorg.900$tE5.231@news-server.bigpond.net.au> David wrote: > I am going around in circles attempting to understand the datsheet for > the BF998 Dual Gate FET. > > From what I can gather, with Vcc = 8V and 4V on G1 and ID of 10mA, at > 150 MHz > Input appears to be 1700 Ohms with 2.1pF par > Output appears to be 1250 Ohms with 1pF par > > (I thought Fets had hundreds of K ohm input impedance - or is this only > at low Freq ?) > > The typology I have is. > > L/C tuned circuit to G1 > 100K+100K providing 4V to G2 (with 100n Bypass cap close to gate) > The source has 100R with 100n Par to ground. > The Drain has the Inductor of the tuned circuit to Vcc (and bypassing on > Vcc side as well as 47R series resistor for additional decoupling). > > The tuning cap goes from Drain to ground. > > I have about 250mV on the source (only 2.5mV bias current). > > How do I obtain 10mA drain current ? Or are they only referring to AC > current ? > > Would someone mind please giving me a bit of overview of these devices. MOSFETs have a very high input resistance, but the actual input impedance at high frequencies is a lot lower. Leon Article: 97904 of rec.radio.amateur.homebrew From: David Subject: Re: Confused with BF998 References: <6Yorg.900$tE5.231@news-server.bigpond.net.au> <1152265054.713381.59030@k73g2000cwa.googlegroups.com> Message-ID: Date: Fri, 07 Jul 2006 11:54:51 GMT Opps, I see my finger trouble. The input was stated as Y = 0.06mS +j 2mS . This would be almost 17K in parallel with 2.1pF NOT 1k7 The output was Y = 0.08mS +j 0.8mS. This should be 12.5k in par with just under 1pF. Not 1250 Ohms OK, I am getting some understanding I just need some gaps filled in now. I see that when the recommended gate voltage is applied to G2 that Rs is adjusted for the required current (say 10mA for lowest noise figure). So, If I put 4V of G2, grounded G1 via and RFC and RFC on drain to Vcc then placed a 100R in the source, I could adjust the 100R till 10mA flowed to set the bias point. I suppose then you would match the 12k drain impedance to a tank circuit. Or place the tank circuit as the load. Is the gain of the amp just related to Gm and the load impedance on the drain. So that if the DC bias was set for specific VDS and VGS then there would be a specific transfer admittance that would produce a current through the load. With RFC there would be max. gain or gain could be fixed by specific load less than this? Thanks Regards David Leon wrote: > David wrote: >> I am going around in circles attempting to understand the datsheet for >> the BF998 Dual Gate FET. >> >> From what I can gather, with Vcc = 8V and 4V on G1 and ID of 10mA, at >> 150 MHz >> Input appears to be 1700 Ohms with 2.1pF par >> Output appears to be 1250 Ohms with 1pF par >> >> (I thought Fets had hundreds of K ohm input impedance - or is this only >> at low Freq ?) >> >> The typology I have is. >> >> L/C tuned circuit to G1 >> 100K+100K providing 4V to G2 (with 100n Bypass cap close to gate) >> The source has 100R with 100n Par to ground. >> The Drain has the Inductor of the tuned circuit to Vcc (and bypassing on >> Vcc side as well as 47R series resistor for additional decoupling). >> >> The tuning cap goes from Drain to ground. >> >> I have about 250mV on the source (only 2.5mV bias current). >> >> How do I obtain 10mA drain current ? Or are they only referring to AC >> current ? >> >> Would someone mind please giving me a bit of overview of these devices. > > MOSFETs have a very high input resistance, but the actual input > impedance at high frequencies is a lot lower. > > Leon > Article: 97905 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Confused with BF998 Message-ID: References: <6Yorg.900$tE5.231@news-server.bigpond.net.au> Date: Fri, 07 Jul 2006 12:17:54 GMT On Fri, 07 Jul 2006 08:29:54 GMT, David wrote: >I am going around in circles attempting to understand the datsheet for >the BF998 Dual Gate FET. > > From what I can gather, with Vcc = 8V and 4V on G1 and ID of 10mA, at >150 MHz >Input appears to be 1700 Ohms with 2.1pF par >Output appears to be 1250 Ohms with 1pF par > >(I thought Fets had hundreds of K ohm input impedance - or is this only >at low Freq ?) At DC and low frequencies the inputs are effectively open circuits (very high R) with a small C across it. As frequency increases the package(leads and all) and that small C combine to reflect a decreasing impedence. Also those numbers are for best noise performance as RF amplifier. > >The typology I have is. > >L/C tuned circuit to G1 >100K+100K providing 4V to G2 (with 100n Bypass cap close to gate) I'd usually use lower value resistors like 10k to ground and 47k to V+ for G2. G1 is returned to ground through tuned circuit L. I use 12V on the drain. >The source has 100R with 100n Par to ground. >The Drain has the Inductor of the tuned circuit to Vcc (and bypassing on > Vcc side as well as 47R series resistor for additional decoupling). > >The tuning cap goes from Drain to ground. > >I have about 250mV on the source (only 2.5mV bias current). > >How do I obtain 10mA drain current ? Or are they only referring to AC >current ? As RF amp or mixer? As RF the bias on G1 and G2 must be correct. For Mixer that would likely not be the case. Allison > >Would someone mind please giving me a bit of overview of these devices. > >Thanks in advance > >Regards > >David Article: 97906 of rec.radio.amateur.homebrew From: "dave" Subject: 813 power amplifier - design safety advice/tips? Message-ID: Date: Fri, 07 Jul 2006 18:04:10 GMT Hello, I am putting together a push-pull power amplifier based on the 813 power tube. It will have about 1.5 to 1.7kV on the plates and put out at least 260 watts into a 9k load. I am not new to high voltage tube circuits, but this is the first time I will be working with potentials this high (above 1kV). I am aware of all of the usual safety precautions, but I was hoping to get some specific tips for putting together a design like this from some people who work with these sort of voltages, hence the posting here. For the plate supply, I have a Hammond power transformer laying around here rated at 1000-0-1000 volts @ 200mA. From the ap notes on the 813, I am know that the tubes will idle at about 50 mA and peak at about 305 mA. Would this Hammond be ok for this type of use? I dont *think* I would be drawing 300 mils anywhere near continuously, but you never know. This amp will be part of a bass guitar amplifier for live performance use. I want to use solid state rectifiers and in studying some older ARRL handbooks, they tell you to use equalizing resistors and small caps across series-strung diodes to get up to the peak inverse voltage you need. However I have seen a newer part in Mouser, made by Rectron, rated at 800mA and 8kV PIV. Would something like this be all I would need (four in a bridge configuration)? I would think it would be easier than making all of those strings up from individual diodes. Or is there a better way? I want to use a choke-input supply and I happen to have a large old filter reactor made by Chicago Transformer rated at 20H @ 250mA, with a test voltage of 6kV. As for filter caps, I guess the cheapest way to go is to string together series electrolytics with balancing resistors. Also I have seen a lot of supplies use soft-start relays in the primary - would you think this would be necessary in this application? I am looking to get about 1.6kV out of this supply. So basically you have a 2000vac secondary feeding a bridge of high voltage rectifier diodes, then a 20H choke, and then a string of 'lytics. How much capacitance would be sufficient to elliminate the hum in the plates? I know that with push-pull and beam power tubes you can probably stang higher ripple in the plates but is there a good ballpark figure? Also since the 813 is directly-heated, would it be ok to have one 10v, 10A filament transformer to light them both or would it be best to have two separate ones to allow for hum balance -pots or for some other reason? I also will have to make a screen supply for 750 volts at 45mA max. Would this have to be a regulated supply? I had planned on ordering some Belden 18awg high voltage test lead wire rated to 10kV for all of the plate supply wiring. Would this be ok, or is there a better wire for this application? By the way I am having Heyboer custom wind an output transformer for this thing. It was fairly expensive (around $200) so I want to protect it as best as possible - fuses, etc - any ideas there? Basically I'm looking for any ideas that might not be at first obvious, in terms of providing safety to me, the operator, or the most exensive components - Any and all ideas/tips/etc. most welcome Dave Article: 97907 of rec.radio.amateur.homebrew From: jo9s8as@yahoo.com Subject: What is a wire antenna's impedance? Date: 7 Jul 2006 12:29:54 -0700 Message-ID: <1152300593.974477.241010@35g2000cwc.googlegroups.com> I searched all over the Internet and many books but just could not find a formula or rough number of a wire antenna's impedance (not dipole or anything else, just a simple, plain wire). I need this number to match my small transmitter's final stage output, about 10mW, at 450MHz. The final stage's transistor has fT of 6GHz, and is not unconditionally stable at 450MHz. So I need to match it using Smith Chart. I know those portion of work. But I just don't know the wire's impedance's range, say, is it in the 50-80 ohms or in the 500-600 ohms range or even 1000-2000 ohms? Right now I do not guess this number right, and my transmitter seems always oscillating at a wrong frequency. So take an example, if I use a wire antenna, say, 22 AWG, spools of solid, and the length=wavelength/4, what is its approximate impedance? Thanks. Article: 97908 of rec.radio.amateur.homebrew From: "Joel Kolstad" Subject: Re: What is a wire antenna's impedance? Date: Fri, 7 Jul 2006 12:46:13 -0700 Message-ID: <12ateg444hqtn52@corp.supernews.com> References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> wrote in message news:1152300593.974477.241010@35g2000cwc.googlegroups.com... >I searched all over the Internet and many books but just could not find > a formula or rough number of a wire antenna's impedance (not dipole or > anything else, just a simple, plain wire). Have you tried "Antennas for All Applications" by Kraus (http://www.amazon.com/gp/product/0072321032/sr=8-1/qid=1152301289/ref=pd_bbs_1/002-7389034-2641652?ie=UTF8)? It has plenty of plots of input impedance for various antennas. Any university library will have some edition of Kraus' book; it's been around for decades. I'm about 99% certain the ARRL handbook has plenty of antenna impledance plots as well. > But I just don't know the wire's impedance's range, > say, is it in the 50-80 ohms or in the 500-600 ohms range or even > 1000-2000 ohms? For most antennas at least in the ballpark of resonance, you'll be in the 30-300 ohm range. Real antennas often have tens to hundreds of ohms of reactance as well, though. > So take an > example, if I use a wire antenna, say, 22 AWG, spools of solid, and the > length=wavelength/4, what is its approximate impedance? In the ballpark of 72 ohms assuming it's a dipole (lambda/4 on either side); if you're operating lambda/4 above a ground plane, it'll be roughly half that. ---Joel Kolstad Article: 97909 of rec.radio.amateur.homebrew From: jo9s8as@yahoo.com Subject: Re: What is a wire antenna's impedance? Date: 7 Jul 2006 13:46:38 -0700 Message-ID: <1152305198.772929.240580@s13g2000cwa.googlegroups.com> References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> Thank you both above. But as I mentioned, I only wanted to know the impedance of a simple, plain wire. No dipole, no complex antenna structure. Please help. Article: 97910 of rec.radio.amateur.homebrew From: "xpyttl" References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> <65hta251poe3h4la7hhl1b1uublk7d8ca1@4ax.com> <1152305198.772929.240580@s13g2000cwa.googlegroups.com> Subject: Re: What is a wire antenna's impedance? Message-ID: Date: Fri, 7 Jul 2006 17:05:34 -0400 As the other posters pointed out, it depends on it's length, where it is above what kind of ground, and how it is fed. It will be influenced by stuff around it like aluminum siding, fences, trees, and all sorts of things. Some of the influences aren't minor, unless they are all wavelengths away. If you have an end-fed quarter wave, which I suspect is what you are describing, then it needs to be fed against something, most likely ground. In that case, it will be about thirty ohms at resonance, plus the resistance of your ground, which could be substantial. That assumes "free space", of course, which isn't bloody likely. More likely you are relatively close to a less than perfect ground, so the impedance could be almost anything. Even in a perfect world, with pefect ground, the impedance varies with height above ground. It isn't like there is some simple answer that is being kept secret. It is a complex question, with lots of variables. As one poster pointed out, the best answer short of measuring it, is to model it with something like EZNEC. You indicated your objective was to come up with some sort of impedance transformation from a rig you are building to this antenna. Given the opportunity for significant reactance, I would suggest you locate someone locally with an antenna analyzer and measure it! An SWR bridge won't tell you enough to design the matching circuit; there will be reactance, and a 2:1 SWR says IF it is all resistive, maybe it is 25 ohms, maybe 100. You have no reason to suspect either and likely there is some reactance so probably it is neither. So go measure it! .. wrote in message news:1152305198.772929.240580@s13g2000cwa.googlegroups.com... > Thank you both above. But as I mentioned, I only wanted to know the > impedance of a simple, plain wire. No dipole, no complex antenna > structure. Please help. > Article: 97911 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: What is a wire antenna's impedance? Message-ID: References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> <65hta251poe3h4la7hhl1b1uublk7d8ca1@4ax.com> <1152305198.772929.240580@s13g2000cwa.googlegroups.com> Date: Fri, 07 Jul 2006 22:23:23 GMT On 7 Jul 2006 13:46:38 -0700, jo9s8as@yahoo.com wrote: >Thank you both above. But as I mentioned, I only wanted to know the >impedance of a simple, plain wire. No dipole, no complex antenna >structure. Please help. Very dependent on length, distance from groundplane, diameter and skin resistance of the material. The best answer is knowing it's only a wire and no defined information more than that is: 42! Allison Article: 97912 of rec.radio.amateur.homebrew From: "Steve N." Subject: Re: quadrature detector & SSB Date: Fri, 7 Jul 2006 17:28:54 -0500 Message-ID: References: "MAc" wrote in message news:e8h9iq$144$1@news.onet.pl... > Steve N. napisa³(a): > > > AD607 does NOT have a "quadrature detector". It has an "I & Q demodulator". > > BIG difference. You must read the datasheet and app notes to use it > > correctly. It is capable of demudulating many types of modulation. [typo > > accepted] > > My mistake, I undersand. But datasheet says nothing more exept "it is > possible to detect ssb with ad607" > > Thanks > MAc OK MAc, All I know is the I & Q modulator and demodulators are the industry standard in commercial radios like the ones my company designs. I hrae that you can get anything you want. I'm too far away from the current designs to know anything specific. A Google resulted in this , but it doesn't appear to be a complete how-to. http://www.merrimacind.com/rfmw/02intro_modulators.pdf Perhaps someone can explain how to "I & Q" to get SSB, etc. Good luck 73, K9DCI Article: 97913 of rec.radio.amateur.homebrew From: MAc Subject: Re: quadrature detector & SSB Date: Sat, 08 Jul 2006 01:18:07 +0200 Message-ID: References: > Perhaps someone can explain how to "I & Q" to get SSB, etc. > The simplest way I found - is to use an ear in companion of brain - :-) I am serious - look for "binaural DC receiver" (Exp. Methods in RF design) when one can see, that "i" is and "q" are simply amplified and feed headphones. Thats all. But then we have still problem with lsb/usb. Thanks for link. MAc sp9mrn Article: 97914 of rec.radio.amateur.homebrew Date: Sat, 08 Jul 2006 01:15:47 +0100 From: Highland Ham Subject: Re: 813 power amplifier - design safety advice/tips? References: Message-ID: 1) The power supply transformer has a centre tap ,hence is meant to be a 1000 V -200 mA ,hence 200Watts supply device. When you would use it as a 2000V-AC device the primary winding and or the 'iron' will highly likely be inadequate to produce 400W of power. So the transformer will NOT be capable of supplying 1600* 0.305 equals 490 Watts. You will need a transformer which can supply at least 2.5 times the power you get from your available transformer . 2)Depending on the transformer voltage available say 1300 V the max rectified DC voltage (due to the capacitor(s) will be 1.4* 1300 equals 1820 V ,hence the PIV of a bridge diode string would have to be at least twice as high ,with a safety factor ,say 4000 if not 5000 V It depends of the type of diode you use but if it is one with a PIV of 1000V you'll need 4 to 5 diodes in a bridge arm string. Modern avalanche diodes are known not needing parallel capacitors or resistors . The Recton diodes are highly likely a molded set of lower PIV diodes . You could find out how many diodes are in series by applying a low forward bias dc current and measure the voltage across the module At approx 0.7 V across each diode you then can determine the number of diodes in the module. You obviously can also use a string of 1N4007 1 Ampere diodes each having a PIV of 1000 V 3)The choke designed for 250 mA might be OK ,although is somewhat marginal .Its resistance will cause a drop of the DC voltage hence in order to get the required final DC supply voltage at max load the transformer voltage has to be adequate . It also means that you have to determine how much 'voltage sagging' is permissable. 4) If you use a string of electrolytic filter capacitors you need a sufficient number to suit the rectifier bridge output voltage multiplied by 1.4 and should apply a decent safety factor. Assuming you use identical caps ,the overall capacitance is of course the value of 1 divided by the number of caps . You have to pay much attention to the equalising resistors taking into account both their voltage and power rating . A well know RF Power Amplifier designer ,AG6K , recommends MOF =Metal Oxide Film resistors , although often one sees high power wire wound resistors on a ceramic core being used. 5) You also need to decide in which operating Class the valves will have to work in view of the acceptable distortion level of the amplifier. Class A would be best but a waste of energy. In the intended push pull configuration Class B would be OK. 6) The screen voltage of both valves will have to be stabilised 7) You also have to ensure that the valves are being cooled ,by means of one or more small fans. A good method is to have an airtight under-chassis pressurised by a small centrifugal fan and the valve sockets fitted just below the chassis (on stand-offs)such that the air flows along the valve bases and up. It might also be useful to apply anode connectors with cooling fins. 8) If amplifier enclosure has a hatch giving access to High Voltage carrying components it is essential that when the hatch is opened a microswitch opens ,cutting all external power if left on. Normally of course power should be cut (power supply plug pulled) and then ,only after a few minutes, the hatch should be opened, because of retention of charge by the filter capacitors for some time (depending on the value of the voltage equalising resistors). These are just a few of many aspects to consider when building a valve power amplifier. Frank GM0CSZ / KN6WH ================================================= > I am putting together a push-pull power amplifier based on the 813 power > tube. It will have about 1.5 to 1.7kV on the plates and put out at least > 260 watts into a 9k load. > > I am not new to high voltage tube circuits, but this is the first time I > will be working with potentials this high (above 1kV). I am aware of all of > the usual safety precautions, but I was hoping to get some specific tips for > putting together a design like this from some people who work with these > sort of voltages, hence the posting here. > > For the plate supply, I have a Hammond power transformer laying around here > rated at 1000-0-1000 volts @ 200mA. From the ap notes on the 813, I am know > that the tubes will idle at about 50 mA and peak at about 305 mA. Would > this Hammond be ok for this type of use? I dont *think* I would be drawing > 300 mils anywhere near continuously, but you never know. This amp will be > part of a bass guitar amplifier for live performance use. > > I want to use solid state rectifiers and in studying some older ARRL > handbooks, they tell you to use equalizing resistors and small caps across > series-strung diodes to get up to the peak inverse voltage you need. > However I have seen a newer part in Mouser, made by Rectron, rated at 800mA > and 8kV PIV. Would something like this be all I would need (four in a > bridge configuration)? I would think it would be easier than making all of > those strings up from individual diodes. Or is there a better way? > > I want to use a choke-input supply and I happen to have a large old filter > reactor made by Chicago Transformer rated at 20H @ 250mA, with a test > voltage of 6kV. > > As for filter caps, I guess the cheapest way to go is to string together > series electrolytics with balancing resistors. > > Also I have seen a lot of supplies use soft-start relays in the primary - > would you think this would be necessary in this application? I am looking > to get about 1.6kV out of this supply. > > So basically you have a 2000vac secondary feeding a bridge of high voltage > rectifier diodes, then a 20H choke, and then a string of 'lytics. How much > capacitance would be sufficient to elliminate the hum in the plates? I know > that with push-pull and beam power tubes you can probably stang higher > ripple in the plates but is there a good ballpark figure? > > Also since the 813 is directly-heated, would it be ok to have one 10v, 10A > filament transformer to light them both or would it be best to have two > separate ones to allow for hum balance -pots or for some other reason? > > I also will have to make a screen supply for 750 volts at 45mA max. Would > this have to be a regulated supply? > > I had planned on ordering some Belden 18awg high voltage test lead wire > rated to 10kV for all of the plate supply wiring. Would this be ok, or is > there a better wire for this application? > > By the way I am having Heyboer custom wind an output transformer for this > thing. It was fairly expensive (around $200) so I want to protect it as > best as possible - fuses, etc - any ideas there? > > Basically I'm looking for any ideas that might not be at first obvious, in > terms of providing safety to me, the operator, or the most exensive > components - > > Any and all ideas/tips/etc. most welcome > > Dave > > > > Article: 97915 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: quadrature detector & SSB Message-ID: <1m4ua25u1ajr0n4qadj3vr50pfkshbmp1r@4ax.com> References: Date: Sat, 08 Jul 2006 02:24:15 GMT On Fri, 7 Jul 2006 17:28:54 -0500, "Steve N." wrote: > >"MAc" wrote in message >news:e8h9iq$144$1@news.onet.pl... >> Steve N. napisa³(a): >> >> > AD607 does NOT have a "quadrature detector". It has an "I & Q >demodulator". >> > BIG difference. You must read the datasheet and app notes to use it >> > correctly. It is capable of demudulating many types of modulation. >[typo >> > accepted] >> >> My mistake, I undersand. But datasheet says nothing more exept "it is >> possible to detect ssb with ad607" >> >> Thanks >> MAc > >OK MAc, > All I know is the I & Q modulator and demodulators are the industry >standard in commercial radios like the ones my company designs. I hrae that >you can get anything you want. I'm too far away from the current designs to >know anything specific. >A Google resulted in this , but it doesn't appear to be a complete how-to. >http://www.merrimacind.com/rfmw/02intro_modulators.pdf > >Perhaps someone can explain how to "I & Q" to get SSB, etc. > >Good luck 73, K9DCI > Havent looked much at the AD part but... it's a mixer (actually two of them). See articles by KK7B and Breed. Basically the I (inphase) and Q (quadrature) mixers are fed with RF at 90 degree relation to each other. The resulting output is then put through a 90degree delay (use 3rd order allpass networks for that) and sum or difference the result and you have a phasing SSB/CW reciever. If you can keep the phase and amplitude errors better than 1% (easy with modern parts) you get 40+ db of alternate sideband suppression. All the work is done in the audio range so Opamps are good for this or DSP. Look up R2, MIniR2, or R2pro for more details. Summary is if you delay the Q path by 90degrees and add the result there will be a frequency(s) where the results add to each other and as you get past zero beat they will subtract from each other. One note on alternate sideband suppression, 40db is pretty good sounding, 50db is achieveable and 60db is tough. I've built a SSB transceiver using the KK7B miniR2 design and opposite sideband suppression is 45db or so and it sounds far better on the air than the typical minimal RX with a 4 crystal ladder filter. I run a MiniR2 and T2 (phasing TX) on 6m with a 6W output. Gets rave reviews for clean signal and it's very good TRX for DX. Allison Article: 97916 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: What is a wire antenna's impedance? Date: Fri, 07 Jul 2006 19:38:05 -0700 Message-ID: <12au6khlbu5kl74@corp.supernews.com> References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> Unfortunately, there's no such thing as a "simple, plain, wire". Any current you put into the wire will force an equal current into the "ground" connection. If, for example, you just plug a wire into the center conductor of your transmitter's output connector, a current will flow out of the connector along the outside transmitter's chassis. This current will equal the current into your wire. So the radio, along with the path to the Earth, becomes the other half of a very asymmetrical dipole. You can't avoid this, except by making the return current flow where you want, for example into the other half of a regular symmetrical dipole. So to simply answer your question, if the wire is very close to a quarter wavelength and connected as I've said, the resistance can be anything from 10 or a few tens of ohms (if it's close to the chassis) to a thousand or more ohms (if the path to the Earth is particular lengths). The reactance can easily be plus or minus a few hundred ohms. That's why you don't find a simple formula. If you did find one, it would be wrong and useless. Roy Lewallen, W7EL jo9s8as@yahoo.com wrote: > I searched all over the Internet and many books but just could not find > a formula or rough number of a wire antenna's impedance (not dipole or > anything else, just a simple, plain wire). I need this number to match > my small transmitter's final stage output, about 10mW, at 450MHz. The > final stage's transistor has fT of 6GHz, and is not unconditionally > stable at 450MHz. So I need to match it using Smith Chart. I know those > portion of work. But I just don't know the wire's impedance's range, > say, is it in the 50-80 ohms or in the 500-600 ohms range or even > 1000-2000 ohms? Right now I do not guess this number right, and my > transmitter seems always oscillating at a wrong frequency. So take an > example, if I use a wire antenna, say, 22 AWG, spools of solid, and the > length=wavelength/4, what is its approximate impedance? Thanks. > Article: 97917 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: 813 power amplifier - design safety advice/tips? Message-ID: References: Date: Sat, 08 Jul 2006 03:03:59 GMT On Fri, 07 Jul 2006 18:04:10 GMT, "dave" wrote: >Hello, > > >I am putting together a push-pull power amplifier based on the 813 power >tube. It will have about 1.5 to 1.7kV on the plates and put out at least >260 watts into a 9k load. > >I am not new to high voltage tube circuits, but this is the first time I >will be working with potentials this high (above 1kV). I am aware of all of >the usual safety precautions, but I was hoping to get some specific tips for >putting together a design like this from some people who work with these >sort of voltages, hence the posting here. > >For the plate supply, I have a Hammond power transformer laying around here >rated at 1000-0-1000 volts @ 200mA. From the ap notes on the 813, I am know >that the tubes will idle at about 50 mA and peak at about 305 mA. Would >this Hammond be ok for this type of use? I dont *think* I would be drawing >300 mils anywhere near continuously, but you never know. This amp will be >part of a bass guitar amplifier for live performance use. If the XFmer is 1000-0-1000 with rectifiers (Full wave configuration) you can count on around 1550V at 200ma or ~310W DC power. You can load that higher if the peak to average is in the 300W range. If you use a full wave bridge you can get twice the voltage and run the same 200ma at ~2800-3000V for 600W. The nasty with a 3000V supply is everything has to stand at least 10KV (allow for transients at least 2x or 3x the supply). Also 813s may arc over at this high a voltage. (use 4-400s!). The caveat is for sound amps and music overbuilding is a good thing. Serious overbuilding is sometime required for commercial (stage) use. Nothing worse than an amp smoking when the perfromer was. Most I knew back when used multiple smaller amps rather than one BIG one all driven from one head. > >I want to use solid state rectifiers and in studying some older ARRL >handbooks, they tell you to use equalizing resistors and small caps across >series-strung diodes to get up to the peak inverse voltage you need. >However I have seen a newer part in Mouser, made by Rectron, rated at 800mA >and 8kV PIV. Would something like this be all I would need (four in a >bridge configuration)? I would think it would be easier than making all of >those strings up from individual diodes. Or is there a better way? Either way works. follow the recommeded add xxx percent over rating to prevent the smoke from escaping. >I want to use a choke-input supply and I happen to have a large old filter >reactor made by Chicago Transformer rated at 20H @ 250mA, with a test >voltage of 6kV. Ok to 250ma and the power xfmer is 200ma so it's a winner to those limits. You can go past that but then heating and peak to average considerations apply (and shorter life is possible). >As for filter caps, I guess the cheapest way to go is to string together >series electrolytics with balancing resistors. It is the way to go. Lots of them! Don't forget all those resistors are eating up that limited 200ma, they are needed but it emphasizes the limited transformer your using. >Also I have seen a lot of supplies use soft-start relays in the primary - >would you think this would be necessary in this application? I am looking >to get about 1.6kV out of this supply. Yes, saves popping mains fuses from power on surges and also is easier on the HV components. FYI: the filliments on the 813s must be up to temp before DC plate or screen power is applied. >So basically you have a 2000vac secondary feeding a bridge of high voltage >rectifier diodes, then a 20H choke, and then a string of 'lytics. How much >capacitance would be sufficient to elliminate the hum in the plates? I know >that with push-pull and beam power tubes you can probably stang higher >ripple in the plates but is there a good ballpark figure? Enough to keep the ripple at full load less than 1%. Start around 60-100uf. See caveat for ~3000V on plates! Pushpull will help balance out ripple. >Also since the 813 is directly-heated, would it be ok to have one 10v, 10A >filament transformer to light them both or would it be best to have two >separate ones to allow for hum balance -pots or for some other reason? One of adaquate current rating with a 50 ohm pot with the wiper to ground for balance will do. That 50ohm pot is a high power resistor. The alternate is a 10V center tapped or two 5V transformers. >I also will have to make a screen supply for 750 volts at 45mA max. Would >this have to be a regulated supply? Absolutely. Likely you will need another transformer, rectifier and filter for that voltage as you only have a 200ma transformer for the plates so why waste some of it on the screens. Also the screen supply must not be applied before the plate voltage. Not needed if you use 811 or other power triode. >I had planned on ordering some Belden 18awg high voltage test lead wire >rated to 10kV for all of the plate supply wiring. Would this be ok, or is >there a better wire for this application? Consider that the environment is not only HV but also HOT. Make sure the wire (and all your parts) can stand heat too. >By the way I am having Heyboer custom wind an output transformer for this >thing. It was fairly expensive (around $200) so I want to protect it as >best as possible - fuses, etc - any ideas there? Fuses should abound. Minimally, mains input, and DC to plate transformer. >Basically I'm looking for any ideas that might not be at first obvious, in >terms of providing safety to me, the operator, or the most exensive >components - ENCLOSE everything with HV on it. Finger proof it. and provide interlocks. Consider cooling as well. >Any and all ideas/tips/etc. most welcome Reminder 2 813s with only filliments lit are pumping out some 100W of heat! (10V at 5A). The tubes should be biased between class AB1 and B for minimum distortion. that means at idle you likely standing 20-50ma per tube (another 50-150W of heat!). You also need a -V (0-100V) negative to bias the tubes. Another small transformer as trivial current is needed mostly for bias pot and bleeders. Mechanical construction is important as with all that iron (transformers) it's going to be heavy. I mean wheels on this beast are a must. You also need a driver and that will have it's own power needs though only a few watts need be developed. The low level amps need to be kept far from the power transformers or it will HUM. Allison > >Dave > > > Article: 97918 of rec.radio.amateur.homebrew From: "Reg Edwards" References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> Subject: Re: What is a wire antenna's impedance? Date: Sat, 8 Jul 2006 04:24:48 +0100 Message-ID: wrote in message news:1152300593.974477.241010@35g2000cwc.googlegroups.com... > I searched all over the Internet and many books but just could not find > a formula or rough number of a wire antenna's impedance (not dipole or > anything else, just a simple, plain wire). I need this number to match > my small transmitter's final stage output, about 10mW, at 450MHz. The > final stage's transistor has fT of 6GHz, and is not unconditionally > stable at 450MHz. So I need to match it using Smith Chart. I know those > portion of work. But I just don't know the wire's impedance's range, > say, is it in the 50-80 ohms or in the 500-600 ohms range or even > 1000-2000 ohms? Right now I do not guess this number right, and my > transmitter seems always oscillating at a wrong frequency. So take an > example, if I use a wire antenna, say, 22 AWG, spools of solid, and the > length=wavelength/4, what is its approximate impedance? Thanks. ======================================== It is not clear what impedance you are talking about. If you are asking what is the Zo impedance of an antenna conductor considered as a transmission line, then it is - Zo = 60 * ( Ln( 4 * L / D ) - 1 ) ohms, where L is length of the conductir, D is its diameter, and Ln is natural logarithms to base e. L and D are in the same measurement units. You have mentioned Smith Charts in your query. Zo is usually in the region of 300 to 600 ohms for wire antennas. The above formula is approximate and is good enough for ordinary purposes. ---- Reg. Article: 97919 of rec.radio.amateur.homebrew From: "Andrew VK3BFA" Subject: Re: 813 power amplifier - design safety advice/tips? Date: 7 Jul 2006 20:59:01 -0700 Message-ID: <1152331141.045643.113600@b28g2000cwb.googlegroups.com> References: nospam@nouce.bellatlantic.net wrote: > On Fri, 07 Jul 2006 18:04:10 GMT, "dave" wrote: > > >Hello, > > > > > >I am putting together a push-pull power amplifier based on the 813 power > >tube. It will have about 1.5 to 1.7kV on the plates and put out at least > >260 watts into a 9k load. > > > >I am not new to high voltage tube circuits, but this is the first time I > >will be working with potentials this high (above 1kV). I am aware of all of > >the usual safety precautions, but I was hoping to get some specific tips for > >putting together a design like this from some people who work with these > >sort of voltages, hence the posting here. > > > >For the plate supply, I have a Hammond power transformer laying around here > >rated at 1000-0-1000 volts @ 200mA. From the ap notes on the 813, I am know > >that the tubes will idle at about 50 mA and peak at about 305 mA. Would > >this Hammond be ok for this type of use? I dont *think* I would be drawing > >300 mils anywhere near continuously, but you never know. This amp will be > >part of a bass guitar amplifier for live performance use. > > If the XFmer is 1000-0-1000 with rectifiers (Full wave configuration) > you can count on around 1550V at 200ma or ~310W DC power. > You can load that higher if the peak to average is in the 300W range. > If you use a full wave bridge you can get twice the voltage and run > the same 200ma at ~2800-3000V for 600W. > > The nasty with a 3000V supply is everything has to stand at least > 10KV (allow for transients at least 2x or 3x the supply). Also 813s > may arc over at this high a voltage. (use 4-400s!). > > The caveat is for sound amps and music overbuilding is a good thing. > Serious overbuilding is sometime required for commercial (stage) > use. Nothing worse than an amp smoking when the perfromer was. > Most I knew back when used multiple smaller amps rather than one > BIG one all driven from one head. > > > > >I want to use solid state rectifiers and in studying some older ARRL > >handbooks, they tell you to use equalizing resistors and small caps across > >series-strung diodes to get up to the peak inverse voltage you need. > >However I have seen a newer part in Mouser, made by Rectron, rated at 800mA > >and 8kV PIV. Would something like this be all I would need (four in a > >bridge configuration)? I would think it would be easier than making all of > >those strings up from individual diodes. Or is there a better way? > > Either way works. follow the recommeded add xxx percent over rating to > prevent the smoke from escaping. > > >I want to use a choke-input supply and I happen to have a large old filter > >reactor made by Chicago Transformer rated at 20H @ 250mA, with a test > >voltage of 6kV. > > Ok to 250ma and the power xfmer is 200ma so it's a winner to those > limits. You can go past that but then heating and peak to average > considerations apply (and shorter life is possible). > > >As for filter caps, I guess the cheapest way to go is to string together > >series electrolytics with balancing resistors. > > It is the way to go. Lots of them! Don't forget all those resistors > are eating up that limited 200ma, they are needed but it emphasizes > the limited transformer your using. > > >Also I have seen a lot of supplies use soft-start relays in the primary - > >would you think this would be necessary in this application? I am looking > >to get about 1.6kV out of this supply. > > Yes, saves popping mains fuses from power on surges and also is > easier on the HV components. > > FYI: the filliments on the 813s must be up to temp before DC plate or > screen power is applied. > > >So basically you have a 2000vac secondary feeding a bridge of high voltage > >rectifier diodes, then a 20H choke, and then a string of 'lytics. How much > >capacitance would be sufficient to elliminate the hum in the plates? I know > >that with push-pull and beam power tubes you can probably stang higher > >ripple in the plates but is there a good ballpark figure? > > Enough to keep the ripple at full load less than 1%. Start around > 60-100uf. > > See caveat for ~3000V on plates! > > Pushpull will help balance out ripple. > > >Also since the 813 is directly-heated, would it be ok to have one 10v, 10A > >filament transformer to light them both or would it be best to have two > >separate ones to allow for hum balance -pots or for some other reason? > > One of adaquate current rating with a 50 ohm pot with the wiper to > ground for balance will do. That 50ohm pot is a high power resistor. > The alternate is a 10V center tapped or two 5V transformers. > > >I also will have to make a screen supply for 750 volts at 45mA max. Would > >this have to be a regulated supply? > > Absolutely. Likely you will need another transformer, rectifier and > filter for that voltage as you only have a 200ma transformer for the > plates so why waste some of it on the screens. Also the screen > supply must not be applied before the plate voltage. > > Not needed if you use 811 or other power triode. > > >I had planned on ordering some Belden 18awg high voltage test lead wire > >rated to 10kV for all of the plate supply wiring. Would this be ok, or is > >there a better wire for this application? > > Consider that the environment is not only HV but also HOT. Make sure > the wire (and all your parts) can stand heat too. > > >By the way I am having Heyboer custom wind an output transformer for this > >thing. It was fairly expensive (around $200) so I want to protect it as > >best as possible - fuses, etc - any ideas there? > > Fuses should abound. Minimally, mains input, and DC to plate > transformer. > > >Basically I'm looking for any ideas that might not be at first obvious, in > >terms of providing safety to me, the operator, or the most exensive > >components - > > ENCLOSE everything with HV on it. Finger proof it. and provide > interlocks. Consider cooling as well. > > >Any and all ideas/tips/etc. most welcome > > Reminder 2 813s with only filliments lit are pumping out some 100W > of heat! (10V at 5A). > > The tubes should be biased between class AB1 and B for minimum > distortion. that means at idle you likely standing 20-50ma per tube > (another 50-150W of heat!). > > You also need a -V (0-100V) negative to bias the tubes. > Another small transformer as trivial current is needed > mostly for bias pot and bleeders. > > Mechanical construction is important as with all that iron > (transformers) it's going to be heavy. I mean wheels on this > beast are a must. > > You also need a driver and that will have it's own power needs > though only a few watts need be developed. The low level amps > need to be kept far from the power transformers or it will HUM. > > > Allison > > > > > >Dave > > > > > > Have you got the audio output transformer for this beastie? - if not, get a price before you start - you might reconsider the project. It is going to be physicaly big, very heavy, and fragile - 813 filaments dont like being knocked around in the back of a truck (and you will need a truck or SUV to move it) so if its intended to go on the road, it might be more trouble than its worth. But, so saying that, ----- nice lunatic fringe project - worth doing, just for the hell of it, and ignore practical realities...... Andrew VK3BFA. Article: 97920 of rec.radio.amateur.homebrew From: "Andrew VK3BFA" Subject: Re: 813 power amplifier - design safety advice/tips? Date: 7 Jul 2006 21:01:33 -0700 Message-ID: <1152331293.525106.187900@m73g2000cwd.googlegroups.com> References: Sorry - didnt read closely enough - you have the output transformer.... Andrew VK3BFA. Article: 97921 of rec.radio.amateur.homebrew From: "Matt J. McCullar" References: <1151699486.365534.315290@y41g2000cwy.googlegroups.com> Subject: Re: Using Garage for Ham Shack Message-ID: Date: Sat, 08 Jul 2006 05:09:35 GMT I spent several years in my teens using my dad's Heathkit SB-102 rig out in the garage in Fort Worth. Yes, it does get hot around here during the summer, make no mistake about it. I'm a night owl by nature, and I can't count how many times I worked DX until the sun came up. Pros and Cons: * Keep the garage door open, and open the back door as well to let air flow through. Cheap, but effective only during the day. At night, june bugs and other critters are attracted by the interior lights and will make life miserable for you. (I'll never forget one on-air conversation when a june bug flew right down my shirt. "WHAAAAUUUGH!!!") These days, unfortunately, it's not wise to leave your garage door open unattended because some *@#$ might come in and steal all of your power tools. (Bitter experience.) Or worse. * Our garage had a VERY good wall-mounted air conditioner. It worked beautifully, even during the long, crushingly hot summer of 1980. In fact, it saved my parents' bacon when the house's main A/C unit failed and it took a couple of days to get it fixed. Mom & Dad just backed the car out of the garage, plopped down a mattress, turned on the wall-mounted A/C, and slept in cool comfort. [I'm sure Dad woke up each morning wondering, "What did she do to the bedroom now?"] Nice backup to have. I could work 40 meters all night long without worrying about the heat or the bugs. * The garage also served as a nice workshop, complete with parts cabinets, two workbenches, and lots of tools. Easy to try out new RF circuits quickly. I like the tornado-shelter idea. It's smaller and easier to keep cool. Also easier to secure valuable equipiment. Article: 97922 of rec.radio.amateur.homebrew From: "dave" References: Subject: Re: 813 power amplifier - design safety advice/tips? Message-ID: Date: Sat, 08 Jul 2006 11:55:19 GMT Thanks to all who responded - some very good points to ponder... I think I should spring for a different plate transformer, since I don't want to be running this one too marginally. Also, I suppose I could do away with the choke and still get under 1% ripple. That would definitely lighten up the weight. The Hammond # 720 is rated 625-0-625 V at 300mA CCS and 500mA ICAS, so I guess that would be adequate. I am using a free program called PSU Designer II to calculate the power supply values and outputs. With the Hammond #720 and a 40uF/47ohm/40uF C-R-C filter after the diode bridge, I should get about 1760VDC at 50mA and about 1660VDC at 300mA. I was also thinking of using three toggle switches across the front panel for filaments, plates, and screens, arranged so as to reflect the order in which to apply the power. I suppose some sort of relay or other device could be used to make sure the screens never got power before or in place of the plates. It is a good idea about the interlocks on the chassis too - I know nobody else will be using this amp besides me but still always a good idea to design in the safety. Also it won't be toured around as I play in basement bands most of the time so it probably won't see too much road use. It's more of a crazy way to generate 300 watts rather than go with the ordinary 'three pairs of KT88 's' route. thanks again sincerely for all the input! Dave Article: 97923 of rec.radio.amateur.homebrew Date: Sat, 08 Jul 2006 16:03:10 +0100 From: Highland Ham Subject: Re: 813 power amplifier - design safety advice/tips? References: Message-ID: > I was also thinking of using three toggle switches across the front panel > for filaments, plates, and screens, arranged so as to reflect the order in > which to apply the power. I suppose some sort of relay or other device > could be used to make sure the screens never got power before or in place of > the plates. It is a good idea about the interlocks on the chassis too - I > know nobody else will be using this amp besides me but still always a good > idea to design in the safety. ===================================== Instead of having 3 separate switches ,go for a single manual switch , a sequential timer or separate timers and have 3 front panel lights for filaments ,anodes and screen voltages. With 3 separate switches you might operate these in the wrong sequence. With the 3 lights to come on sequentially you quickly can detect any possible sequential switching problems. Frank GM0CSZ / KN6WH Article: 97924 of rec.radio.amateur.homebrew From: John - KD5YI Subject: Re: How to calculate increase of home wireless router range? References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> Message-ID: Date: Sat, 08 Jul 2006 16:08:23 GMT Rod Speed wrote: > Geoffrey S. Mendelson wrote > >>Rod Speed wrote > > >>>>Is one transmit and the other receive? >>>>Or are they both transmit and receive? > > >>>They're normally both transmit and receive. > > >>That's a shame. Here in Israel we are limited to 100mw EIRP, which severly >>limits the transmit antenna. There is NO limitation on the receive antenna. > > > A receive antenna has no EIRP, it doesnt radiate any real power. > > Actually, when properly matched, it radiates half the received power. Article: 97925 of rec.radio.amateur.homebrew From: "Don K" References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> Subject: Re: How to calculate increase of home wireless router range? Date: Sat, 8 Jul 2006 13:37:45 -0400 Message-ID: "John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01... > Rod Speed wrote: >> >> A receive antenna has no EIRP, it doesnt radiate any real power. > > Actually, when properly matched, it radiates half the received power. How do you get that? If the receiver input impedance is matched to the antenna, all the received power is absorbed. There is no reflection. There is no radiation. If the receiver matching is for optimal noise figure, there may be some reflection and reradiation, but there's nothing pinning it to be half the received power. Don Article: 97926 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: How to calculate increase of home wireless router range? Date: Sat, 08 Jul 2006 12:26:18 -0700 Message-ID: <12b01murlm8kt86@corp.supernews.com> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> Don K wrote: > "John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01... >> Rod Speed wrote: >>> A receive antenna has no EIRP, it doesnt radiate any real power. >> Actually, when properly matched, it radiates half the received power. > > > How do you get that? > If the receiver input impedance is matched to the antenna, all the > received power is absorbed. There is no reflection. There is no radiation. > > If the receiver matching is for optimal noise figure, there may be > some reflection and reradiation, but there's nothing pinning it to > be half the received power. John is correct. A receiving antenna, when matched, reradiates half the power it receives. An impinging field induces current in the antenna. This causes radiation, just like the current in a transmitting antenna. As it turns out, when the antenna is matched, the amount of power radiated equals the amount of power delivered to the load, and that's the best you can do. If you'd like a more in-depth and mathematical explanation, you can find it in any antenna text, often discussed as "scattering". If a receiving antenna did absorb all the impinging power, it would be a lot easier to make a shield or a stealth aircraft. Roy Lewallen, W7EL Article: 97927 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 9 Jul 2006 05:35:39 +1000 Message-ID: <4hafodF1pqdbmU1@individual.net> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> John - KD5YI wrote: > Rod Speed wrote: >> Geoffrey S. Mendelson wrote >> >>> Rod Speed wrote >> >> >>>>> Is one transmit and the other receive? >>>>> Or are they both transmit and receive? >> >> >>>> They're normally both transmit and receive. >> >> >>> That's a shame. Here in Israel we are limited to 100mw EIRP, which >>> severly limits the transmit antenna. There is NO limitation on the >>> receive antenna. >> >> >> A receive antenna has no EIRP, it doesnt radiate any real power. >> >> > > > Actually, when properly matched, it radiates half the received power. Wrong. Article: 97928 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 9 Jul 2006 05:39:30 +1000 Message-ID: <4hafvkF1qu4d3U1@individual.net> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> Roy Lewallen wrote > Don K wrote >> John - KD5YI wrote >>> Rod Speed wrote >>>> A receive antenna has no EIRP, it doesnt radiate any real power. >>> Actually, when properly matched, it radiates half the received power. >> How do you get that? >> If the receiver input impedance is matched to the antenna, all the >> received power is absorbed. There is no reflection. There is no >> radiation. >> If the receiver matching is for optimal noise figure, there may be >> some reflection and reradiation, but there's nothing pinning it to >> be half the received power. > John is correct. Nope. > A receiving antenna, when matched, reradiates half the power it receives. Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > An impinging field induces current in the antenna. This causes radiation, just like the > current in a transmitting antenna. As it turns out, when the antenna is matched, the > amount of power radiated equals the amount of power delivered to the load, and that's > the best you can do. Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > If you'd like a more in-depth and mathematical explanation, you can find it in any > antenna text, often discussed as "scattering". Not relevant to the original point, any effect on the EIRP restriction. > If a receiving antenna did absorb all the impinging power, it would be a lot easier to > make a shield or a stealth aircraft. Not relevant to the original point, any effect on the EIRP restriction. Article: 97929 of rec.radio.amateur.homebrew Message-ID: <44B018D3.2020900@w2agn.net> Date: Sat, 08 Jul 2006 16:42:59 -0400 From: "John L. Sielke" Subject: Re: How to calculate increase of home wireless router range? References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> Rod Speed wrote: > Roy Lewallen wrote >> Don K wrote >>> John - KD5YI wrote >>>> Rod Speed wrote > >>>>> A receive antenna has no EIRP, it doesnt radiate any real power. > >>>> Actually, when properly matched, it radiates half the received power. > >>> How do you get that? >>> If the receiver input impedance is matched to the antenna, all the >>> received power is absorbed. There is no reflection. There is no >>> radiation. > >>> If the receiver matching is for optimal noise figure, there may be >>> some reflection and reradiation, but there's nothing pinning it to >>> be half the received power. > >> John is correct. > > Nope. > >> A receiving antenna, when matched, reradiates half the power it receives. > > Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > >> An impinging field induces current in the antenna. This causes radiation, just like the >> current in a transmitting antenna. As it turns out, when the antenna is matched, the >> amount of power radiated equals the amount of power delivered to the load, and that's >> the best you can do. > > Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > >> If you'd like a more in-depth and mathematical explanation, you can find it in any >> antenna text, often discussed as "scattering". > > Not relevant to the original point, any effect on the EIRP restriction. > >> If a receiving antenna did absorb all the impinging power, it would be a lot easier to >> make a shield or a stealth aircraft. > > Not relevant to the original point, any effect on the EIRP restriction. > > Always amazinmg how when some people are proven wrong, the revert to the "Is NOT, IS NOT," type of argument used by small children, then when that doesn't work, the argument becomes irrelevant. Rod, I suggest you LEARN something from your intellectual and technical betters BEFORE you show the world your ignorance. John Article: 97930 of rec.radio.amateur.homebrew Date: Sat, 08 Jul 2006 16:45:20 -0400 From: "John L. Sielke" Subject: Re: How to calculate increase of home wireless router range? References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> Message-ID: Rod Speed wrote: > Roy Lewallen wrote >> Don K wrote >>> John - KD5YI wrote >>>> Rod Speed wrote > >>>>> A receive antenna has no EIRP, it doesnt radiate any real power. > >>>> Actually, when properly matched, it radiates half the received power. > >>> How do you get that? >>> If the receiver input impedance is matched to the antenna, all the >>> received power is absorbed. There is no reflection. There is no >>> radiation. > >>> If the receiver matching is for optimal noise figure, there may be >>> some reflection and reradiation, but there's nothing pinning it to >>> be half the received power. > >> John is correct. > > Nope. > >> A receiving antenna, when matched, reradiates half the power it receives. > > Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > >> An impinging field induces current in the antenna. This causes radiation, just like the >> current in a transmitting antenna. As it turns out, when the antenna is matched, the >> amount of power radiated equals the amount of power delivered to the load, and that's >> the best you can do. > > Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > >> If you'd like a more in-depth and mathematical explanation, you can find it in any >> antenna text, often discussed as "scattering". > > Not relevant to the original point, any effect on the EIRP restriction. > >> If a receiving antenna did absorb all the impinging power, it would be a lot easier to >> make a shield or a stealth aircraft. > > Not relevant to the original point, any effect on the EIRP restriction. > > Always amazinmg how when some people are proven wrong, the revert to the "Is NOT, IS NOT," type of argument used by small children, then when that doesn't work, the argument becomes irrelevant. Rod, I suggest you LEARN something from your intellectual and technical betters BEFORE you show the world your ignorance. John Article: 97931 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: How to calculate increase of home wireless router range? Date: Sat, 08 Jul 2006 14:00:56 -0700 Message-ID: <12b078dq4db14bf@corp.supernews.com> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> Rod Speed wrote: > Roy Lewallen wrote > . . . >> A receiving antenna, when matched, reradiates half the power it receives. > > Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > . . . It's real power, but that power all comes from the impinging field; it's not contributing any new power. So you're right that the EIRP restriction doesn't apply. The receive antenna reduces the amount of power in the field by the amount delivered to the antenna's termination, plus any losses along the way. The intent of the EIRP restriction is to limit the amount of field strength added by a transmitter. Roy Lewallen, W7EL Article: 97932 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 9 Jul 2006 07:12:11 +1000 Message-ID: <4halddF1qsfidU1@individual.net> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> John L. Sielke wrote: > Rod Speed wrote: >> Roy Lewallen wrote >>> Don K wrote >>>> John - KD5YI wrote >>>>> Rod Speed wrote >> >>>>>> A receive antenna has no EIRP, it doesnt radiate any real power. >> >>>>> Actually, when properly matched, it radiates half the received >>>>> power. >> >>>> How do you get that? >>>> If the receiver input impedance is matched to the antenna, all the >>>> received power is absorbed. There is no reflection. There is no >>>> radiation. >> >>>> If the receiver matching is for optimal noise figure, there may be >>>> some reflection and reradiation, but there's nothing pinning it to >>>> be half the received power. >> >>> John is correct. >> >> Nope. >> >>> A receiving antenna, when matched, reradiates half the power it >>> receives. >> >> Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. >> >>> An impinging field induces current in the antenna. This causes >>> radiation, just like the current in a transmitting antenna. As it >>> turns out, when the antenna is matched, the amount of power >>> radiated equals the amount of power delivered to the load, and >>> that's the best you can do. >> >> Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. >> >>> If you'd like a more in-depth and mathematical explanation, you can >>> find it in any antenna text, often discussed as "scattering". >> >> Not relevant to the original point, any effect on the EIRP >> restriction. >> >>> If a receiving antenna did absorb all the impinging power, it would >>> be a lot easier to make a shield or a stealth aircraft. >> >> Not relevant to the original point, any effect on the EIRP >> restriction. > Always amazinmg how when some people are proven wrong, the > revert to the "Is NOT, IS NOT," type of argument used by small > children, then when that doesn't work, the argument becomes irrelevant. Never ever could bullshit its way out of a wet paper bag. > Rod, I suggest you LEARN something from your intellectual and > technical betters BEFORE you show the world your ignorance. Never ever could bullshit its way out of a wet paper bag. While your original was technically correct, its completely irrelevant to what was actually being discussed, WHETHER THE RECEIVE ANTENNA EVER RADIATES ENOUGH TO BE RELEVANT TO THE EIRP RESTRICTION. Article: 97933 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 9 Jul 2006 07:15:05 +1000 Message-ID: <4halirF1q1aemU1@individual.net> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <12b078dq4db14bf@corp.supernews.com> Roy Lewallen wrote: > Rod Speed wrote: >> Roy Lewallen wrote >> . . . >>> A receiving antenna, when matched, reradiates half the power it >>> receives. >> >> Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > It's real power, Yes, BUT NOT IN THE EIRP RESTRICTION SENSE. > but that power all comes from the impinging field; it's not contributing any new power. > So you're right that the EIRP restriction doesn't apply. And that is what was being discussed when John made such a spectacular fool of himself mindlessly rabbiting on about what is no news to anyone with a clue about receiving antennas. > The receive antenna reduces the amount of power in the field by the amount delivered to > the antenna's termination, plus any losses along the way. The intent of the EIRP > restriction is to limit the amount of field strength added by a > transmitter. Duh. So John was mindlessly rabbiting on about a complete irrelevancy WHEN THE EIRP RESTRICTION WAS BEING DISCUSSED. Article: 97934 of rec.radio.amateur.homebrew From: Mark McIntyre Subject: Re: How to calculate increase of home wireless router range? Date: Sat, 08 Jul 2006 23:08:34 +0100 Message-ID: References: <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> On Sun, 9 Jul 2006 07:12:11 +1000, in alt.internet.wireless , "Rod Speed" wrote: >John L. Sielke wrote: > >> Always amazinmg how when some people are proven wrong, the >> revert to the "Is NOT, IS NOT," type of argument used by small >> children, then when that doesn't work, the argument becomes irrelevant. > >Never ever could bullshit its way out of a wet paper bag. > >> Rod, I suggest you LEARN something from your intellectual and >> technical betters BEFORE you show the world your ignorance. > >Never ever could bullshit its way out of a wet paper bag. > >While your original was technically correct, its completely >irrelevant to what was actually being discussed, WHETHER >THE RECEIVE ANTENNA EVER RADIATES ENOUGH TO >BE RELEVANT TO THE EIRP RESTRICTION. I've not been following this thread, but I can tell you straight off, I am significantly more inclined to believe the guys who are not shouting and hurling abuse. Make of that what you will, but my suggestion is to counter with rational argument backed up by references and facts, rather than insults and obscenities. -- Mark McIntyre Article: 97935 of rec.radio.amateur.homebrew Message-ID: <44B03E09.BB75BE9A@notxy.com> From: kyle Subject: Re: need part References: Date: Sat, 08 Jul 2006 23:21:47 GMT hi http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm nte online xref search reports NTE2377 as substitute part mouser.com has them in stock $ 11.39 no min. order needed. ships same day as ordered. http://www.mouser.com/search/refine.aspx?Ntt=nte2377 73 kyle Article: 97936 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 9 Jul 2006 09:30:46 +1000 Message-ID: <4hath8F1r3h9lU1@individual.net> References: <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> Mark McIntyre wrote > Rod Speed wrote >> John L. Sielke wrote >>> Always amazinmg how when some people are proven wrong, the >>> revert to the "Is NOT, IS NOT," type of argument used by small >>> children, then when that doesn't work, the argument becomes irrelevant. >> Never ever could bullshit its way out of a wet paper bag. >>> Rod, I suggest you LEARN something from your intellectual and >>> technical betters BEFORE you show the world your ignorance. >> Never ever could bullshit its way out of a wet paper bag. >> While your original was technically correct, its completely >> irrelevant to what was actually being discussed, WHETHER >> THE RECEIVE ANTENNA EVER RADIATES ENOUGH TO >> BE RELEVANT TO THE EIRP RESTRICTION. > I've not been following this thread, but I can tell you > straight off, I am significantly more inclined to believe > the guys who are not shouting and hurling abuse. You have always been, and always will be, completely and utterly irrelevant. What you may or may not be inclined to believe in spades. Anyone with a clue considers the facts, not the style stuff, fuckwit. > Make of that what you will, I flush it where it belongs. > but my suggestion is to counter with rational > argument backed up by references and facts, Dont need 'references' on that basic fact that even when the receiving antenna does reradiate about half of what it receives, THAT IS COMPLETELY IRRELEVANT TO THE LEGISLATED ERIP LEVEL. > rather than insults and obscenities. I suggest you take your stupid suggestion and shove it up your arse, where it belongs. Article: 97937 of rec.radio.amateur.homebrew From: "Don K" References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> Subject: Re: How to calculate increase of home wireless router range? Date: Sat, 8 Jul 2006 20:50:07 -0400 Message-ID: "Roy Lewallen" wrote in message news:12b01murlm8kt86@corp.supernews.com... > Don K wrote: >> "John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01... >>> Rod Speed wrote: >>>> A receive antenna has no EIRP, it doesnt radiate any real power. >>> Actually, when properly matched, it radiates half the received power. >> >> >> How do you get that? >> If the receiver input impedance is matched to the antenna, all the >> received power is absorbed. There is no reflection. There is no radiation. >> >> If the receiver matching is for optimal noise figure, there may be >> some reflection and reradiation, but there's nothing pinning it to >> be half the received power. > > John is correct. A receiving antenna, when matched, reradiates half the power it receives. An > impinging field induces current in the antenna. This causes radiation, just like the current in a > transmitting antenna. As it turns out, when the antenna is matched, the amount of power radiated > equals the amount of power delivered to the load, and that's the best you can do. If you'd like a > more in-depth and mathematical explanation, you can find it in any antenna text, often discussed > as "scattering". > > If a receiving antenna did absorb all the impinging power, it would be a lot easier to make a > shield or a stealth aircraft. > > Roy Lewallen, W7EL Maybe to some extent, it's a matter of nit-picking over what "received power" means. You can think of an antenna as having an effective aperture size over which it captures all the energy crossing that cross-sectional area. To me it's logical to think of "received power" as the power that actually gets scooped up and delivered. Effective aperture increases with antenna gain. Obviously something like a dipole has a relatively small effective aperture. But the effective aperture of a high-gain horn antenna for instance, will approach its actual physical cross-sectional area. For instance, look at Figure 13 in this pdf. http://www.coe.montana.edu/ee/rwolff/EE548/EE548-S06/UWB/Intro_UWBAntennas.pdf Don Article: 97938 of rec.radio.amateur.homebrew From: John - KD5YI Subject: Re: How to calculate increase of home wireless router range? References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <4hafodF1pqdbmU1@individual.net> Message-ID: Date: Sun, 09 Jul 2006 01:43:49 GMT Rod Speed wrote: > John - KD5YI wrote: > >>Rod Speed wrote: >> >>>Geoffrey S. Mendelson wrote >>> >>> >>>>Rod Speed wrote >>> >>> >>>>>>Is one transmit and the other receive? >>>>>>Or are they both transmit and receive? >>> >>> >>>>>They're normally both transmit and receive. >>> >>> >>>>That's a shame. Here in Israel we are limited to 100mw EIRP, which >>>>severly limits the transmit antenna. There is NO limitation on the >>>>receive antenna. >>> >>> >>>A receive antenna has no EIRP, it doesnt radiate any real power. >>> >>> >> >> >>Actually, when properly matched, it radiates half the received power. > > > Wrong. Wrong. Article: 97939 of rec.radio.amateur.homebrew From: "Mike, who else?" Subject: Re: looking for 2 metre mobile radio References: <44ae07f7$1$21440$afc38c87@news.optusnet.com.au> Message-ID: Date: Sun, 09 Jul 2006 05:27:55 GMT On Fri, 07 Jul 2006 17:06:41 +1000, hamguy1 wrote: > hi there newgroups, i live in australia im looking for either a yaesu > kenwood icom or similar 2 metre for my mobile with dtmf mic preferably if > anyone in the usa etc has 1 i would pay shipping to australia .thanks in > advance david nsw australia . www.ebay.com Article: 97940 of rec.radio.amateur.homebrew From: xray Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 09 Jul 2006 03:00:23 -0700 Message-ID: <9pj1b2hie3r7lfkmf92i3ulahgkq4up92a@4ax.com> References: <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> <4hath8F1r3h9lU1@individual.net> On Sun, 9 Jul 2006 09:30:46 +1000, "Rod Speed" wrote, in part: >What you may or may not be inclined to believe in spades. That assemblage does not appear to be a sentence. > >Anyone with a clue considers the facts, not the style stuff, fuckwit. But it is distracting when you choose to code your message content in the style of an illiterate A-hole. I also think you should have said "content" rather than "facts." Most of what you have been posting here recently seems to be opinion rather than fact. Article: 97941 of rec.radio.amateur.homebrew From: Mark McIntyre Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 09 Jul 2006 11:21:59 +0100 Message-ID: <43m1b21l1tq69s9lkgr6lrmgj4l5v7h072@4ax.com> References: <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> <4hath8F1r3h9lU1@individual.net> On Sun, 9 Jul 2006 09:30:46 +1000, in alt.internet.wireless , "Rod Speed" wrote: >You have always been, and always will be, completely and utterly irrelevant. Oh, I've just recognised your name. Conversation over, I don't waste my time talking to the sort of fool who thinks that because they're hiding on usenet they can emit language which would get them a severe slapping in real life. Nobody cares what you think. Not even you. *plonk* -- Mark McIntyre Article: 97942 of rec.radio.amateur.homebrew Date: Sun, 09 Jul 2006 09:16:15 -0500 From: Arlon Nelson Subject: Part Pinout Message-ID: I'm in need of the pinout of a 3SK274 Dual Gate Mosfet. It has one short lead and 3 long leads. I have check my ARRL handbooks and cannot find out which one is source,drain,g1 and g2 Thanks for any help Nels W0TUP Article: 97943 of rec.radio.amateur.homebrew From: "Eamon Skelton" Subject: Re: Part Pinout References: Message-ID: Date: Sun, 09 Jul 2006 15:01:41 GMT On Sun, 09 Jul 2006 09:16:15 -0500, Arlon Nelson wrote: > I'm in need of the pinout of a 3SK274 Dual Gate Mosfet. It has one short > lead and 3 long leads. > I have check my ARRL handbooks and cannot find out which one is > source,drain,g1 and g2 > > Thanks for any help > > Nels W0TUP What type of package is it in? The Toshiba data-sheet says it is a gual-gate GaAs FET in a surface mount package. Your description sounds more like a TO-50 pill or X type package. Most Japanese dual-gate FETs in pill packages use the same pinout as the BF981. The long lead is probably the drain, although I have seen a few that had a long lead for G1. 73, Ed. EI9GQ -- Remove 'X' to reply by e-mail. Linux 2.6.17 Article: 97944 of rec.radio.amateur.homebrew From: jo9s8as@yahoo.com Subject: Re: What is a wire antenna's impedance? Date: 9 Jul 2006 09:37:56 -0700 Message-ID: <1152463076.490252.133390@b28g2000cwb.googlegroups.com> References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> Thanks, everyone. But you guys still made things complicated. I said it is just wire antenna, only for a very small output power, 10mW. In order to eliminate the confusion or misunderstanding, let me put some pictures to illustrate: (1) This transmitter, 10mW, at 450MHz, wire length(lambda/4 for 450MHz)=16cm. What is the wire antenna's impedance? http://www.charto.info/antq1.jpg (2) This transmitter, 10MW, at 450MHz, Rod Extendable Antenna is extended exactly as 16cm(lambda/4 for 450MHz). What is its antenna's impedance? http://www.charto.info/antq2.jpg Given that such specific conditions are as shown in the pictures, is it still difficult to tell, even for a rough number within a range such as 50 to 80 ohms, or 500-800 ohms? Article: 97945 of rec.radio.amateur.homebrew From: John - KD5YI Subject: Re: What is a wire antenna's impedance? References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> <1152463076.490252.133390@b28g2000cwb.googlegroups.com> Message-ID: <96bsg.3011$pB.2982@trnddc06> Date: Sun, 09 Jul 2006 17:33:57 GMT jo9s8as@yahoo.com wrote: > Thanks, everyone. But you guys still made things complicated. No, they didn't. Antennas themselves are complicated. Formulas exist only for specific well-defined environments, none of which fits your configuration close enough to be meaningful. > I said it > is just wire antenna, only for a very small output power, 10mW. Output power has nothing to do with antenna impedance. > In > order to eliminate the confusion or misunderstanding, let me put some > pictures to illustrate: > > (1) This transmitter, 10mW, at 450MHz, wire length(lambda/4 for > 450MHz)=16cm. What is the wire antenna's impedance? > http://www.charto.info/antq1.jpg > (2) This transmitter, 10MW, at 450MHz, Rod Extendable Antenna is > extended exactly as 16cm(lambda/4 for 450MHz). What is its antenna's > impedance? > http://www.charto.info/antq2.jpg > > Given that such specific conditions are as shown in the pictures, is it > still difficult to tell, even for a rough number within a range such as > 50 to 80 ohms, or 500-800 ohms? Yes, it is. And, whatever number you are given will not necessarily be correct from one time to another. The impedance will change if you pick up the radio or the camera. The impedance will change if you change position to be near another object. Suppose you are told that the impedance will be 20-j35? What will you do about it? Since you feel that the expert advice you received simply complicated the issue, one can only assume that you do not have the knowledge to cope with an answer. Go to your local ham club and find somebody with an antenna analyzer. Put a quarter-wave wire into the connector and wander around while recording the maximum resistance and reactance. You can see it change all over the place. No, it doesn't go from zero to infinity. The impedance will be different >from that when the antenna is installed on your actual object. Here is a number. Do with it what you will.... Z ~ 35-j35. If you don't like this number, get EZNEC and model your own antenna. Or, get your own analyzer and measure your wire. Be sure to include hand and body capacitance in your model. Also be sure to model your tripod, soil conditions, nearby trees, the object enclosure, etc. Good luck. John Article: 97946 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Mon, 10 Jul 2006 04:10:46 +1000 Message-ID: <4hcv58F1qgjuqU1@individual.net> References: <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> <4hath8F1r3h9lU1@individual.net> <9pj1b2hie3r7lfkmf92i3ulahgkq4up92a@4ax.com> xray wrote: > Rod Speed wrote > Most of what you have been posting here > recently seems to be opinion rather than fact. Best get your seems machinery seen to then. Its a fact that even when a receiving antenna does radiate back half of what it recieves, THAT IS NOT RELEVANT TO WHAT WAS BEING DISCUSSED, THE LEGISLATED EIRP LEVEL ALLOWED. Not a shred of opinion involved what so ever. Article: 97947 of rec.radio.amateur.homebrew From: "Oscar Jones" References: <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> <4hath8F1r3h9lU1@individual.net> <43m1b21l1tq69s9lkgr6lrmgj4l5v7h072@4ax.com> Subject: Re: How to calculate increase of home wireless router range? Date: Mon, 10 Jul 2006 04:11:48 +1000 Message-ID: <44b146e5$0$17543$61c65585@un-2park-reader-01.sydney.pipenetworks.com.au> Some terminal fuckwit claiming to be Mark McIntyre wrote just the puerile shit thats all it can ever manage. Article: 97948 of rec.radio.amateur.homebrew Subject: Re: quadrature detector & SSB From: charlesh3@msn.com References: Date: Sun, 9 Jul 2006 19:36:35 GMT Message-ID: Hi - The best not-terribly-mathematical place to get started probably is a Popular Electronics (of all places) article from '82 called "Build a Synchronous Detector for AM Radio" by Dave Hershberger. Chuck Article: 97949 of rec.radio.amateur.homebrew From: "MarkAren" Subject: Re: Part Pinout Date: 9 Jul 2006 12:50:45 -0700 Message-ID: <1152474645.651376.35850@h48g2000cwc.googlegroups.com> References: See http://www.alldatasheet.co.kr/datasheet-pdf/pdf_kor/TOSHIBA/3SK274.html -Mark. Arlon Nelson wrote: > I'm in need of the pinout of a 3SK274 Dual Gate Mosfet. It has one short > lead and 3 long leads. > I have check my ARRL handbooks and cannot find out which one is > source,drain,g1 and g2 > > Thanks for any help > > Nels W0TUP Article: 97950 of rec.radio.amateur.homebrew From: Rex Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 09 Jul 2006 13:12:30 -0700 Message-ID: References: <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> <4hath8F1r3h9lU1@individual.net> <9pj1b2hie3r7lfkmf92i3ulahgkq4up92a@4ax.com> <4hcv58F1qgjuqU1@individual.net> On Mon, 10 Jul 2006 04:10:46 +1000, "Rod Speed" wrote: >xray wrote: >> Rod Speed wrote > > > >> Most of what you have been posting here >> recently seems to be opinion rather than fact. > >Best get your seems machinery seen to then. > >Its a fact that even when a receiving antenna does radiate back >half of what it recieves, THAT IS NOT RELEVANT TO WHAT WAS >BEING DISCUSSED, THE LEGISLATED EIRP LEVEL ALLOWED. > >Not a shred of opinion involved what so ever. > Look at this part of the thread... [John said:] If the receiver matching is for optimal noise figure, there may be some reflection and reradiation, but there's nothing pinning it to be half the received power. [Roy said:] John is correct. [Rod said:] Nope. [Roy said:] A receiving antenna, when matched, reradiates half the power it receives. [Rod said:] Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. --- So John made a factual statment. Roy agreed. Your opinion was to disagree with the simple factual statment. Roy added a clarifying statment. You started to go off the hook and SHOUT because you were fixated on EIRP. When I read it I never saw any direct implication about EIRP or legalities in the explanation; it was a simple explanation about antennas. Your *opinion* was involved in deciding you knew the exact intent of the posting and that it had implications in the EIRP thing, just because that is the interpretation that passed through your mind. Ok, I'm done here. Not sure why I took the time for this one last post. Article: 97951 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Mon, 10 Jul 2006 06:25:14 +1000 Message-ID: <4hd71cF1qjo3vU1@individual.net> References: <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <4hafvkF1qu4d3U1@individual.net> <44B018D3.2020900@w2agn.net> <4halddF1qsfidU1@individual.net> <4hath8F1r3h9lU1@individual.net> <9pj1b2hie3r7lfkmf92i3ulahgkq4up92a@4ax.com> <4hcv58F1qgjuqU1@individual.net> Rex wrote > Rod Speed wrote >> xray wrote >>> Rod Speed wrote >>> Most of what you have been posting here >>> recently seems to be opinion rather than fact. >> Best get your seems machinery seen to then. >> Its a fact that even when a receiving antenna does radiate back >> half of what it recieves, THAT IS NOT RELEVANT TO WHAT WAS >> BEING DISCUSSED, THE LEGISLATED EIRP LEVEL ALLOWED. >> Not a shred of opinion involved what so ever. > Look at this part of the thread... > [John said:] > If the receiver matching is for optimal noise figure, there may be > some reflection and reradiation, but there's nothing pinning it to > be half the received power. > > [Roy said:] > John is correct. > > [Rod said:] > Nope. Not about that particular para of John's. I was saying that John was not correct on the original point about whatever the receiving anntenna radiates BEING RELEVANT TO THE LEGISLATED EIRP LEVEL. No opinion there, just fact. > [Roy said:] > A receiving antenna, when matched, reradiates half the power it > receives. > [Rod said:] > Yes but that ISNT ANY REAL POWER in the EIRP restriction sense. > --- > So John made a factual statment. Roy agreed. It wasnt relevant to what was actually being discussed, WHETHER WHATEVER THE RECEIVING ANTENNA RADIATES HAS ANYTHING TO DO WITH THE LEGISLATED EIRP WAS ACTUALLY BEING DISCUSSED. > Your opinion was to disagree with the simple factual statment. It wasnt an opinion, it was a statement of fact that that comment John made WAS NOT RELEVANT TO THE LEGISLATED EIRP LEVEL THAT WAS BEING DISCUSSED. > Roy added a clarifying statment. You started to go off the > hook and SHOUT because you were fixated on EIRP. The legislated EIRP level WAS WHAT WAS BEING DISCUSSED WHEN JOHN MADE SUCH A SPECTACULAR FOOL OF HIMSELF RABBITING ON ABOUT WHAT THE RECIEVING ANTENNA RADIATES. > When I read it I never saw any direct implication about EIRP or legalities > in the explanation; it was a simple explanation about antennas. Pity it was a comment made WHEN THE LEGISLATED EIRP LEVEL WAS BEING DISCUSSED WITH REFERENCE TO THE RECEIVING ANTENNA. > Your *opinion* was involved in deciding you knew the exact intent of the posting Wrong again. It is a FACT that John's comment had no relevance what so ever to what was being discussed, whether the receiving antenna has any relevance what so ever to the legislated EIRP level. It doesnt. > and that it had implications in the EIRP thing, just because > that is the interpretation that passed through your mind. Nothing to do with my mind, it was what was being discussed. > Ok, I'm done here. Not sure why I took the time for this one last post. Yeah, you just made a VERY spectacular fool of yourself, yet again. Article: 97952 of rec.radio.amateur.homebrew From: Jeff Liebermann Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 09 Jul 2006 13:33:43 -0700 Message-ID: References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> [misc.consumers.frugal-living dropped from distribution list.] Roy Lewallen hath wroth: >Don K wrote: >> "John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01... >>> Rod Speed wrote: >>>> A receive antenna has no EIRP, it doesnt radiate any real power. >>> Actually, when properly matched, it radiates half the received power. >> >> >> How do you get that? >> If the receiver input impedance is matched to the antenna, all the >> received power is absorbed. There is no reflection. There is no radiation. >> >> If the receiver matching is for optimal noise figure, there may be >> some reflection and reradiation, but there's nothing pinning it to >> be half the received power. > >John is correct. A receiving antenna, when matched, reradiates half the >power it receives. An impinging field induces current in the antenna. >This causes radiation, just like the current in a transmitting antenna. >As it turns out, when the antenna is matched, the amount of power >radiated equals the amount of power delivered to the load, and that's >the best you can do. If you'd like a more in-depth and mathematical >explanation, you can find it in any antenna text, often discussed as >"scattering". > >If a receiving antenna did absorb all the impinging power, it would be a >lot easier to make a shield or a stealth aircraft. > >Roy Lewallen, W7EL I'm not so sure. I couldn't find any specific references to this effect in several books I skimmed. Same with internet searches. If true, then the concept of converting solar power in an orbital satellite, converting it to microwaves, beaming it down to an antenna array in the middle of the desert, and converting it back to electricity, isn't going to work if the array re-radiates half the power. That's going to ruin quite a few nifty science fiction stories and innovative business plans. I also note that the common microwave path analysis calculations don't take re-radiation into account. For example, if I start with an EIRP of perhaps XX dBm from a transmit antenna, -YY dB of path loss, and ZZ dB receive antenna gain, the power delivered to the receiver (ignoring coax losses) is calculated at (XX - YY + ZZ) dBm without any mention of the -3dB that would need to be subtracted if half the receive power is re-radiated from the rx antenna. It would seem that the common formula and web forms for link calculations are -3dB off. I trust your judgement in such matters and you have far more expience than me, but something seems wrong or I'm missing something. Can you point me to any books or refernences? I just skimmed Chapter 2 (Fundamentals of Antennas) in "Antenna Engineering Handbook" by Jasik (1961) and found no obvious mention of this effect. -- Jeff Liebermann jeffl@comix.santa-cruz.ca.us 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 Article: 97953 of rec.radio.amateur.homebrew From: John - KD5YI Subject: Re: How to calculate increase of home wireless router range? References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> Message-ID: Date: Sun, 09 Jul 2006 21:40:28 GMT Jeff Liebermann wrote: > [misc.consumers.frugal-living dropped from distribution list.] > > Roy Lewallen hath wroth: > > >>Don K wrote: >> >>>"John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01... >>> >>>>Rod Speed wrote: >>>> >>>>>A receive antenna has no EIRP, it doesnt radiate any real power. >>>> >>>>Actually, when properly matched, it radiates half the received power. >>> >>> >>>How do you get that? >>>If the receiver input impedance is matched to the antenna, all the >>>received power is absorbed. There is no reflection. There is no radiation. >>> >>>If the receiver matching is for optimal noise figure, there may be >>>some reflection and reradiation, but there's nothing pinning it to >>>be half the received power. >> >>John is correct. A receiving antenna, when matched, reradiates half the >>power it receives. An impinging field induces current in the antenna. >>This causes radiation, just like the current in a transmitting antenna. >>As it turns out, when the antenna is matched, the amount of power >>radiated equals the amount of power delivered to the load, and that's >>the best you can do. If you'd like a more in-depth and mathematical >>explanation, you can find it in any antenna text, often discussed as >>"scattering". >> >>If a receiving antenna did absorb all the impinging power, it would be a >>lot easier to make a shield or a stealth aircraft. >> >>Roy Lewallen, W7EL > > > I'm not so sure. I couldn't find any specific references to this > effect in several books I skimmed. Same with internet searches. If > true, then the concept of converting solar power in an orbital > satellite, converting it to microwaves, beaming it down to an antenna > array in the middle of the desert, and converting it back to > electricity, isn't going to work if the array re-radiates half the > power. That's going to ruin quite a few nifty science fiction stories > and innovative business plans. > > I also note that the common microwave path analysis calculations don't > take re-radiation into account. For example, if I start with an EIRP > of perhaps XX dBm from a transmit antenna, -YY dB of path loss, and ZZ > dB receive antenna gain, the power delivered to the receiver (ignoring > coax losses) is calculated at (XX - YY + ZZ) dBm without any mention > of the -3dB that would need to be subtracted if half the receive power > is re-radiated from the rx antenna. It would seem that the common > formula and web forms for link calculations are -3dB off. > > I trust your judgement in such matters and you have far more expience > than me, but something seems wrong or I'm missing something. Can you > point me to any books or refernences? I just skimmed Chapter 2 > (Fundamentals of Antennas) in "Antenna Engineering Handbook" by Jasik > (1961) and found no obvious mention of this effect. > Antennas For All Applications by John D. Kraus and Ronald J. Marhefka Third Edition Page 746, Paragraph 21-15 "Prec=(Rr/(Ra+Rr))Pa where Rr=receiver impedance, ohms Ra=antenna radiation resistance, ohms For a perfect match, Rr=Ra, so that Prec=(Rr/(Rr+Rr))Pa=0.5Pa (W) and the receiver gets 1/2 the power collected by the antenna. The other half is reradiated." Also see "TV and Other Receiving Antennas" by Arnold B. Bailey published in 1950 by Rider Publishing. Beginning on page 235 near the bottom: "In radio receiving antennas the predominant resistance is, strangely enough, largely due to the fact that no electrons can move on the antenna surface *without also sending radio energy back out into space*. So here we have the paradox of a receiving antenna, having the prime function of collecting or extracting energy from space, but unable to do so *without itself returning radio energy of like kind* into space. The amount which it returns is one-half of the total that it extracts under properly matched conditions. In a good installation, with the antenna properly connected to its receiver load, the receiving antenna will be able to *deliver to its load one-half of the energy* it extracts from the oncoming radio wave but, by necessity, *must return the other half to free space*. A receiving antenna, then, is itself a *new source* of radiation. This is not so surprising, since *any* reflecting surface, as we have seen, establishes a new source of radiation" (Note: The emphasis in the book was italics) Cheers, John Article: 97955 of rec.radio.amateur.homebrew From: Mark McIntyre Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 09 Jul 2006 22:49:02 +0100 Message-ID: References: <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> On Sun, 09 Jul 2006 13:33:43 -0700, in alt.internet.wireless , Jeff Liebermann wrote: >[misc.consumers.frugal-living dropped from distribution list.] > >Roy Lewallen hath wroth: > >>John is correct. A receiving antenna, when matched, reradiates half the >>power it receives. >>If a receiving antenna did absorb all the impinging power, it would be a >>lot easier to make a shield or a stealth aircraft. >> > >I'm not so sure. I couldn't find any specific references to this >effect in several books I skimmed. > >I trust your judgement in such matters and you have far more expience >than me, but something seems wrong or I'm missing something. Can you >point me to any books or refernences? I just skimmed Chapter 2 >(Fundamentals of Antennas) in "Antenna Engineering Handbook" by Jasik >(1961) and found no obvious mention of this effect. Scroggie's "Foundations of Wireless", the book I cut my teeth on (and my father before me...) mentions this in the chapter on Radiation and Aerials where he describes the reratiation as a fact of great importance in recieving aerial design. I think however Rod's final remark is perhaps the most telling - if an antenna really did absorb all the energy landing on it, there would be highly curious side effects. -- Mark McIntyre Article: 97956 of rec.radio.amateur.homebrew From: "Bob D." Subject: Computer alternative to Smith Chart? Date: Sun, 9 Jul 2006 17:30:57 -0500 Message-ID: I haven't used a Smith Chart in over 30 years, and to say the least, I'm a bit rusty. I'm thinking there must be computer programs that can do the calculations with values you just plugs in. Any recommendations? I'm specifically interested in finding the impedances of antenna whips much shorter than 1/4 wave. -- Bob D. ND9B Article: 97957 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: What is a wire antenna's impedance? Date: Sun, 09 Jul 2006 16:02:29 -0700 Message-ID: <12b32o61rrsfke3@corp.supernews.com> References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> <1152463076.490252.133390@b28g2000cwb.googlegroups.com> jo9s8as@yahoo.com wrote: > Thanks, everyone. But you guys still made things complicated. I said it > is just wire antenna, only for a very small output power, 10mW. In > order to eliminate the confusion or misunderstanding, let me put some > pictures to illustrate: > > (1) This transmitter, 10mW, at 450MHz, wire length(lambda/4 for > 450MHz)=16cm. What is the wire antenna's impedance? > http://www.charto.info/antq1.jpg > (2) This transmitter, 10MW, at 450MHz, Rod Extendable Antenna is > extended exactly as 16cm(lambda/4 for 450MHz). What is its antenna's > impedance? > http://www.charto.info/antq2.jpg > > Given that such specific conditions are as shown in the pictures, is it > still difficult to tell, even for a rough number within a range such as > 50 to 80 ohms, or 500-800 ohms? Absolutely. You could get a pretty good idea of the impedance of the antenna with a carefully constructed model and a modeling program if the device case is metal and you assume that the device won't be anywhere near a person or other conducting object. If it is, the person or object has to be included in the model. There's no nifty and simple equation or rule of thumb which will tell you. You don't seem to understand that the "antenna" is only part of the antenna whose impedance you're asking. The other part is the box and whatever it's attached to or whomever is holding it. The "antenna"'s impact on the impedance is no greater or less than the impact of the rest of the real antenna, i.e., the box and what it's connected to. If the box is plastic, then internal wires and boards are the other part of the real antenna, and have a major impact on the impedance. Roy Lewallen, W7EL Article: 97958 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Computer alternative to Smith Chart? Date: Sun, 09 Jul 2006 16:04:36 -0700 Message-ID: <12b32s4aliba388@corp.supernews.com> References: I'm curious. How do you use a Smith chart to find an antenna impedance? There certainly are programs specifically designed to find such things as antenna impedances. The free EZNEC demo program from http://eznec.com would be adequate and ideal for your purpose. Roy Lewallen, W7EL Bob D. wrote: > I haven't used a Smith Chart in over 30 years, and to say the least, I'm a > bit rusty. I'm thinking there must be computer programs that can do the > calculations with values you just plugs in. Any recommendations? I'm > specifically interested in finding the impedances of antenna whips much > shorter than 1/4 wave. Article: 97959 of rec.radio.amateur.homebrew From: Jeff Liebermann Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 09 Jul 2006 19:02:09 -0700 Message-ID: References: <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> John - KD5YI hath wroth: >Antennas For All Applications by John D. Kraus and Ronald J. Marhefka >Third Edition >Page 746, Paragraph 21-15 > >"Prec=(Rr/(Ra+Rr))Pa > >where > >Rr=receiver impedance, ohms >Ra=antenna radiation resistance, ohms > >For a perfect match, Rr=Ra, so that > >Prec=(Rr/(Rr+Rr))Pa=0.5Pa (W) > >and the receiver gets 1/2 the power collected by the antenna. The other half >is reradiated." OK, that make sense. Thanks much. So, why is NASA and other disreputable organizations still pushing beaming solar power down to earth via microwaves? | http://en.wikipedia.org/wiki/Solar_power_satellite | http://en.wikipedia.org/wiki/Microwave_power_transmission | http://science.nasa.gov/headlines/y2001/ast23mar_1.htm | http://www.spacefuture.com/archive/conceptual_study_of_a_solar_power_satellite_sps_2000.shtml | http://www.msfc.nasa.gov/news/news/releases/1999/99-096.html | http://www.ieee-virtual-museum.org/exhibit/exhibit.php?id=159265&lid=1&seq=13 No mention in any of these that half the delivered power gets re-radiated. If the receive array were anywhere as directional as the xmit array, then it would cook the satellite. The re-radiated power has to go somewhere. Oh, maybe because it's a government project the number don't need to be correct? I'll spare you the usual anal joke about rectenna. Also, why is there no -3dB added loss on the receive end of wireless path calculation? From what I can deduce from the path calcs, the receive antenna delivers all the power to the coax cable and then to the receiver. Where's the half power (-3dB) loss? I'm still (half way) mystified. >Also see "TV and Other Receiving Antennas" by Arnold B. Bailey published in >1950 by Rider Publishing. Beginning on page 235 near the bottom: Argh. That was published 2 years after I was born. >"In radio receiving antennas the predominant resistance is, strangely >enough, largely due to the fact that no electrons can move on the antenna >surface *without also sending radio energy back out into space*. Resistance? Unless he's thinking of ohmic resistance, most antennas don't have any resistance. (Well, a rhombic has a 300-400 ohm load, but that's not what we're discussing). If the signal gets re-radiated, without any loss, there can't be any dissipative elements in the system. What resistance? -- Jeff Liebermann jeffl@comix.santa-cruz.ca.us 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 Article: 97960 of rec.radio.amateur.homebrew From: "littleflurry" Subject: foulradio.com Message-ID: <_Risg.1651$2v.208@newssvr25.news.prodigy.net> Date: Mon, 10 Jul 2006 02:22:50 GMT This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C6A39D.CF3AD490 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Lots of fun with this midwest duo!=20 foulradio.com ------=_NextPart_000_0006_01C6A39D.CF3AD490 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Lots of fun with this midwest duo!

foulradio.com

------=_NextPart_000_0006_01C6A39D.CF3AD490-- Article: 97961 of rec.radio.amateur.homebrew From: budgie Subject: Re: Computer alternative to Smith Chart? Date: Mon, 10 Jul 2006 12:43:30 +0800 Message-ID: References: On Sun, 9 Jul 2006 17:30:57 -0500, "Bob D." wrote: >I haven't used a Smith Chart in over 30 years, and to say the least, I'm a >bit rusty. I'm thinking there must be computer programs that can do the >calculations with values you just plugs in. Any recommendations? I'm >specifically interested in finding the impedances of antenna whips much >shorter than 1/4 wave. There's a nice impedance spiral in Kraus: "Antennas". Article: 97962 of rec.radio.amateur.homebrew From: dplatt@radagast.org (Dave Platt) Subject: Re: Computer alternative to Smith Chart? Date: Mon, 10 Jul 2006 05:11:02 -0000 Message-ID: <12b3ob6mss62208@corp.supernews.com> References: >>I haven't used a Smith Chart in over 30 years, and to say the least, I'm a >bit rusty. I'm thinking there must be computer programs that can do the >calculations with values you just plugs in. Any recommendations? For Linux (and probably other Unix-type systems running X) there's a nice free program called Linsmith. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! Article: 97963 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: How to calculate increase of home wireless router range? Date: Sun, 09 Jul 2006 22:15:00 -0700 Message-ID: <12b3oil818krpe3@corp.supernews.com> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> Jeff Liebermann wrote: > > I'm not so sure. I couldn't find any specific references to this > effect in several books I skimmed. Same with internet searches. If > true, then the concept of converting solar power in an orbital > satellite, converting it to microwaves, beaming it down to an antenna > array in the middle of the desert, and converting it back to > electricity, isn't going to work if the array re-radiates half the > power. That's going to ruin quite a few nifty science fiction stories > and innovative business plans. > > I also note that the common microwave path analysis calculations don't > take re-radiation into account. For example, if I start with an EIRP > of perhaps XX dBm from a transmit antenna, -YY dB of path loss, and ZZ > dB receive antenna gain, the power delivered to the receiver (ignoring > coax losses) is calculated at (XX - YY + ZZ) dBm without any mention > of the -3dB that would need to be subtracted if half the receive power > is re-radiated from the rx antenna. It would seem that the common > formula and web forms for link calculations are -3dB off. > > I trust your judgement in such matters and you have far more expience > than me, but something seems wrong or I'm missing something. Can you > point me to any books or refernences? I just skimmed Chapter 2 > (Fundamentals of Antennas) in "Antenna Engineering Handbook" by Jasik > (1961) and found no obvious mention of this effect. I could add more references to the ones already mentioned, but you should be able to find it in most antenna texts. Look in the index under aperture and scattering cross section. When dealing with path loss calculations, the effective aperture is used, and this has the reradiation already accounted for. In fact, the reradiated power has its own descriptive unit, the scattering aperture. A good and brief description of these can be found in Kraus' _Antennas_, p. 29ff, and many other texts. You're right that the antennas used to receive beamed power will catch only half of it at best. But many, many business plans have been developed and billions in stock sold for schemes which are much less plausible. For starters, how about the current idea of hydrogen "fuel", "made from water"? (For those not acquainted with the harsh reality of thermodynamics, it takes more energy to extract hydrogen from water than you'll get back when you burn it. Charlatans notwithstanding, there's just flat no way around this little fact.) Then there's SDI. . . Roy Lewallen, W7EL Article: 97964 of rec.radio.amateur.homebrew From: John Navas Subject: Re: How to calculate increase of home wireless router range? Message-ID: References: <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <12b01murlm8kt86@corp.supernews.com> <12b3oil818krpe3@corp.supernews.com> Date: Mon, 10 Jul 2006 05:30:55 GMT On Sun, 09 Jul 2006 22:15:00 -0700, Roy Lewallen wrote in <12b3oil818krpe3@corp.supernews.com>: >You're right that the antennas used to receive beamed power will catch >only half of it at best. But many, many business plans have been >developed and billions in stock sold for schemes which are much less >plausible. For starters, how about the current idea of hydrogen "fuel", >"made from water"? (For those not acquainted with the harsh reality of >thermodynamics, it takes more energy to extract hydrogen from water than >you'll get back when you burn it. Charlatans notwithstanding, there's >just flat no way around this little fact.) Then there's SDI. . . The point of hydrogen is a means of energy storage and transmission, not power generation. Typically the hydrogen will be released from water by solar or nuclear power. See: >http://www.aip.org/pt/vol-57/iss-12/p39.html> -- Best regards, FAQ for Wireless Internet: John Navas FAQ for Wi-Fi: Wi-Fi How To: Fixes to Wi-Fi Problems: Article: 97965 of rec.radio.amateur.homebrew From: Ben Jackson Subject: Toroid or molded inductor in low voltage tank? Message-ID: Date: Mon, 10 Jul 2006 01:50:58 -0500 In a coupling circuit such as: C1|| C3|| IN>----||----o----o----||--OUT> || | | || --- C --- C L1 C2| C | | '----' | === GND (see, eg, the "38 Special" NorCal 30m QRP tranceiver sch connecting the NE602 single-ended output to an amplification stage: http://www.amqrp.org/kits/38spcl/ ) What is the purpose maximizing the Q of L1 by using, say, a hand- wound toroid vs a molded inductor? Rs of a 1.8uH moulded inductor might be 1.5 ohms vs .1 ohm for 5 inches of 24ga wire. However the expected effect in tank bandwidth doesn't seem to matter compared to the large effect of varying C1 (very narrow for small C1, 5p in the example). I can see why a homebrewer would prefer to keep a bag of T37-2 and some enamelled wire around, but in a kit such as that, wouldn't a moulded inductor do just as well? -- Ben Jackson AD7GD http://www.ben.com/ Article: 97966 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Toroid or molded inductor in low voltage tank? Date: Mon, 10 Jul 2006 00:49:19 -0700 Message-ID: <12b41k06r8inu93@corp.supernews.com> References: The much lower Q of the molded inductor can result in significantly worse rejection of spurious outputs from the amplifier. I don't know whether that's important for this particular design or not. But a toroid also has other advantages over a solenoidal inductor. A toroid has a much smaller external field, so it can be mounted close to other components including other inductors with minimal mutual coupling. For the same reason, a solenoid's Q can be degraded substantially by proximity to other components or conductors, while a toroid is relatively immune to this problem. Roy Lewallen, W7EL Ben Jackson wrote: > In a coupling circuit such as: > > C1|| C3|| > IN>----||----o----o----||--OUT> > || | | || > --- C > --- C L1 > C2| C > | | > '----' > | > === > GND > > (see, eg, the "38 Special" NorCal 30m QRP tranceiver sch connecting > the NE602 single-ended output to an amplification stage: > http://www.amqrp.org/kits/38spcl/ ) > > What is the purpose maximizing the Q of L1 by using, say, a hand- > wound toroid vs a molded inductor? Rs of a 1.8uH moulded inductor > might be 1.5 ohms vs .1 ohm for 5 inches of 24ga wire. However the > expected effect in tank bandwidth doesn't seem to matter compared to > the large effect of varying C1 (very narrow for small C1, 5p in the > example). > > I can see why a homebrewer would prefer to keep a bag of T37-2 and > some enamelled wire around, but in a kit such as that, wouldn't a > moulded inductor do just as well? > Article: 97968 of rec.radio.amateur.homebrew From: "W3JDR" References: Subject: Re: Toroid or molded inductor in low voltage tank? Message-ID: Date: Mon, 10 Jul 2006 09:59:19 GMT Ben, Don't confuse the 'unloaded' Q of the part with the 'loaded Q' of the circuit. The unloaded Q of the part is a measure of internal resistance in the part and will mainly affect the loss of the network, not the bandwidth. The loaded Q of the network is a measure of the external network resistance that the part is embedded in and will mainly determine the bandwidth. The ratio of unloaded Q to loaded Q will determine the losses of the network (higher unloaded Q is better). In general, high unloaded component Q is 'goodness'. Joe W3JDR "Ben Jackson" wrote in message news:slrneb3u6i.172.ben@saturn.home.ben.com... > In a coupling circuit such as: > > C1|| C3|| > IN>----||----o----o----||--OUT> > || | | || > --- C > --- C L1 > C2| C > | | > '----' > | > === > GND > > (see, eg, the "38 Special" NorCal 30m QRP tranceiver sch connecting > the NE602 single-ended output to an amplification stage: > http://www.amqrp.org/kits/38spcl/ ) > > What is the purpose maximizing the Q of L1 by using, say, a hand- > wound toroid vs a molded inductor? Rs of a 1.8uH moulded inductor > might be 1.5 ohms vs .1 ohm for 5 inches of 24ga wire. However the > expected effect in tank bandwidth doesn't seem to matter compared to > the large effect of varying C1 (very narrow for small C1, 5p in the > example). > > I can see why a homebrewer would prefer to keep a bag of T37-2 and > some enamelled wire around, but in a kit such as that, wouldn't a > moulded inductor do just as well? > > -- > Ben Jackson AD7GD > > http://www.ben.com/ Article: 97969 of rec.radio.amateur.homebrew From: jo9s8as@yahoo.com Subject: Re: Computer alternative to Smith Chart? Date: 10 Jul 2006 05:20:08 -0700 Message-ID: <1152534008.905417.146880@h48g2000cwc.googlegroups.com> References: Smith Chart 3.0 is great. http://www.antennadesignassociates.com/smithexample.gif Article: 97970 of rec.radio.amateur.homebrew From: AB2RC Subject: Re: Computer alternative to Smith Chart? References: Message-ID: Date: Mon, 10 Jul 2006 12:20:41 GMT On 2006-07-09, Bob D. wrote: > I haven't used a Smith Chart in over 30 years, and to say the least, I'm a > bit rusty. I'm thinking there must be computer programs that can do the > calculations with values you just plugs in. Any recommendations? I'm > specifically interested in finding the impedances of antenna whips much > shorter than 1/4 wave. For real operating systems (anything Unix based -- Linux OSX or a real Unix) try Linsmith http://jcoppens.com/soft/linsmith/index.en.php Article: 97971 of rec.radio.amateur.homebrew From: "Reg Edwards" References: Subject: Re: Computer alternative to Smith Chart? Date: Mon, 10 Jul 2006 14:33:17 +0100 Message-ID: <7bmdnZ8kucZ8yi_ZRVny0Q@bt.com> You will find half dozen programs which deal with performance of short verticals at the website below. >From the Index, go to "Download programs from here" and read the one-line description under each program name. ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 97972 of rec.radio.amateur.homebrew Date: Tue, 11 Jul 2006 00:29:49 +1000 From: Andrew Tweddle Subject: Re: Computer alternative to Smith Chart? References: Message-ID: <44b263a2$1_1@news.chariot.net.au> Bob D. wrote: > I haven't used a Smith Chart in over 30 years, and to say the least, I'm a > bit rusty. I'm thinking there must be computer programs that can do the > calculations with values you just plugs in. Any recommendations? I'm > specifically interested in finding the impedances of antenna whips much > shorter than 1/4 wave. You could try this one. regards Andrew Article: 97973 of rec.radio.amateur.homebrew From: John - KD5YI Subject: Re: Computer alternative to Smith Chart? References: Message-ID: Date: Mon, 10 Jul 2006 17:00:03 GMT Bob D. wrote: > I haven't used a Smith Chart in over 30 years, and to say the least, I'm a > bit rusty. I'm thinking there must be computer programs that can do the > calculations with values you just plugs in. Any recommendations? I'm > specifically interested in finding the impedances of antenna whips much > shorter than 1/4 wave. Hi, Bob - http://zaffora.f2o.org/W9DMK/W9dmk.html has one. About 3/4 of the way down the page. It won't help you find antenna impedance unless you plan to measure the Z at the input end of the line and use the tool to get antenna Z. As has been said, you can use EZNEC to model your antenna and get its impedance. However, a Smith chart can be very useful for matching a thing to another thing. The one I use (a demo) I got from the University of Applied Sciences in Berne, Switzerland. I like it. However, it appears that it has been removed >from the host. If you want it, I can send it to you. It is zipped to 306 kb in size. Cheers, John Article: 97974 of rec.radio.amateur.homebrew From: "AndyS" Subject: Re: Computer alternative to Smith Chart? Date: 10 Jul 2006 13:45:32 -0700 Message-ID: <1152564332.319191.323380@75g2000cwc.googlegroups.com> References: Andy adds: I have often used a modified Smith Chart , called an Impedance/Admittance chart , to do matching..... If the impedances are not greatly mismatched, it is very easy and accurate.... and very very intuitive... The ones I used have the impedance cordinates in black and the admittance coordinates in red..... I found them extremly useful in the design of an automated antenna tuner which I designed for a Texas Instruments Marine SSB unit, back in the late 70s..... You could literally track the impedance transormation mentally with series and shunt elements..... Andy W4OAH Article: 97975 of rec.radio.amateur.homebrew From: Invalid@charter.net Subject: Re: How to calculate increase of home wireless router range? Message-ID: References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> Date: Mon, 10 Jul 2006 18:11:13 -0400 On Sat, 08 Jul 2006 16:08:23 GMT, John - KD5YI wrote: >Rod Speed wrote: >> Geoffrey S. Mendelson wrote >> >>>Rod Speed wrote >> >> >>>>>Is one transmit and the other receive? >>>>>Or are they both transmit and receive? >> >> >>>>They're normally both transmit and receive. >> >> >>>That's a shame. Here in Israel we are limited to 100mw EIRP, which severly >>>limits the transmit antenna. There is NO limitation on the receive antenna. >> >> >> A receive antenna has no EIRP, it doesnt radiate any real power. >> >> > > >Actually, when properly matched, it radiates half the received power. True, but it's such a low level as to normally be considered insignificant. Unfortunately some take that to mean there is none. If there were none, a Yagi antenna which used all passive elements save for the driven element would not work. On receive that driven element plays an active (pardon the pun) roll. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com Roger Article: 97976 of rec.radio.amateur.homebrew From: Invalid@charter.net Subject: Re: How to calculate increase of home wireless router range? Message-ID: References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <6_xqg.86010$uP.64508@newsfe2-gui.ntli.net> <11of8oney2ztt.1rzsok8gvo9mf.dlg@40tude.net> Date: Mon, 10 Jul 2006 18:24:27 -0400 On Tue, 4 Jul 2006 21:31:06 +0000 (UTC), gsm@mendelson.com (Geoffrey S. Mendelson) wrote: >Beverly Erlebacher wrote: >> I'm confused about this "access point" thing. > >An access point is a device with an ethernet port on one side and a wifi >port on the other. In technical terms it would be called a "bridge". It >"bridges" two seperate network segments, although in this case they use >different topologies (100Base-T and WiFi). > >> Is that the same as a "router"? > > >The usual WiFi router consists of a four port ethernet hub (LAN ports), >a seperate single ethernet port (WAN port) and a WiFi access point. >It is set up to "route" between the single (aka WAN) port and the other >two ports, the LAN and WiFi. Most of what it does for routing is NAT (network >address translation) and some sort of IP tunneling. > >If you ignore the WAN port and just use the LAN ports, you have a four port >hub and an access point. > > >> Is it as simple as buying a second router (routers are familiar to me) and >> just hooking that second router to the first router by cable and that would >> extend my range by the distance of the cable connecting the two routers? > >Yes. Just make sure to use the LAN ports. It would be best to use different >channels. Most WiFi clients are smart enough to use the channel that is the >strongest if they have access points on more than one with the same SSID. > >Make sure to use encryption. Encryption is NOT to keep your data safe, >nothing can do that. If someone is intent on accessing your network, WEP >encryption will not keep them out. True, but the ones that use the dynamic encryption can do a reasonably good job along with a firewall and router. The golden rule is "Nothing is bullet proof" > >What it is for is to convince the guy driving down the street looking for an >open network to send out SPAM, or "share" kiddie porn, to drive on. >Unfortunately, most users don't even change the SSID of their network, let >alone set an encryption key. > One of the locals mentioned doing a bit of "war driving" around town just for curiosity. About 80 to 90% of the networks heard were unencrypted AND over half of those _still_used_ the_default_name_and_PW. I use hard wired Cat5e in a gigabit network as with the amount of traffic wireless is just too slow even if it is full duplex. NOTE I only receive the two amateur radio news groups. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com >Having tuned in late, if you want to have an open network, look up PublicIP. >It's a "live cd" that runs on a PII or better (x86) computer and provides >all the functions you need to offer a secure and safe open network. > >Geoff. Roger Article: 97977 of rec.radio.amateur.homebrew From: "K7ITM" Subject: Re: Toroid or molded inductor in low voltage tank? Date: 10 Jul 2006 15:27:14 -0700 Message-ID: <1152570434.601377.304290@35g2000cwc.googlegroups.com> References: For a quick graphic demonstration of what the other posters are pointing out without having to build and measure a physical circuit, try putting this circuit into "RFSim99" (a free program), and select "Use physical model" in the inductor value dialog box. Then change the unloaded Q of the inductor there to see the effects on performance, both loss and filter sharpness (--> rejection of unwanted signals). You'll need to connect "IN" and "OUT" to measurement ports (one of the available components in RFSim99) that you set to appropriate impedances. Such a simulation doesn't address the effects that Roy mentioned of coupling to external fields and lowering of Q by coupling to external material. On the other hand, though toroid coils have lower coupling to externals, their coupling isn't zero, especially when you use a low-mu core---so be careful how you mount the toroids, too. In a couple minutes, the simulation can give you some insights to get you started and save a lot of time soldering, but expect to ultimately learn even more by actually building and measuring the circuit. Cheers, Tom Ben Jackson wrote: > In a coupling circuit such as: > > C1|| C3|| > IN>----||----o----o----||--OUT> > || | | || > --- C > --- C L1 > C2| C > | | > '----' > | > === > GND > > (see, eg, the "38 Special" NorCal 30m QRP tranceiver sch connecting > the NE602 single-ended output to an amplification stage: > http://www.amqrp.org/kits/38spcl/ ) > > What is the purpose maximizing the Q of L1 by using, say, a hand- > wound toroid vs a molded inductor? Rs of a 1.8uH moulded inductor > might be 1.5 ohms vs .1 ohm for 5 inches of 24ga wire. However the > expected effect in tank bandwidth doesn't seem to matter compared to > the large effect of varying C1 (very narrow for small C1, 5p in the > example). > > I can see why a homebrewer would prefer to keep a bag of T37-2 and > some enamelled wire around, but in a kit such as that, wouldn't a > moulded inductor do just as well? > > -- > Ben Jackson AD7GD > > http://www.ben.com/ Article: 97978 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Tue, 11 Jul 2006 08:34:24 +1000 Message-ID: <4hg2viF1r60boU1@individual.net> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> Invalid@charter.net wrote > John - KD5YI wrote >> Rod Speed wrote >>> Geoffrey S. Mendelson wrote >>>> Rod Speed wrote >>>>>> Is one transmit and the other receive? >>>>>> Or are they both transmit and receive? >>>>> They're normally both transmit and receive. >>>> That's a shame. Here in Israel we are limited to >>>> 100mw EIRP, which severly limits the transmit >>>> antenna. There is NO limitation on the receive antenna. >>> A receive antenna has no EIRP, it doesnt radiate any real power. >> Actually, when properly matched, it radiates half the received power. > True, but it's such a low level as to normally be considered insignificant. Which is what I said in different words. > Unfortunately some take that to mean there is none. The word REAL was used for a reason. > If there were none, a Yagi antenna which used all passive > elements save for the driven element would not work. On > receive that driven element plays an active (pardon the pun) roll. Having fun thrashing that straw man are you ? Article: 97979 of rec.radio.amateur.homebrew From: Ben Jackson Subject: Re: Toroid or molded inductor in low voltage tank? References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> Message-ID: Date: Mon, 10 Jul 2006 18:10:04 -0500 On 2006-07-10, K7ITM wrote: > try putting this circuit into "RFSim99" (a free program) Thanks, I'd been looking for something like that. > unloaded Q of the inductor there to see the effects on performance, > both loss and filter sharpness (--> rejection of unwanted signals). I see. So the reason that the Q matters so much is not that it affects the filter shape much (in this topology), but that it has a big effect on the amplitude of the (tiny) passband which provides additional separation from the unwanted signals. In this case it looks like raising from Q=50 to 250 gives about 4dB of "wanted" signal without really affecting anything else. > couple minutes, the simulation can give you some insights to get you > started and save a lot of time soldering, but expect to ultimately > learn even more by actually building and measuring the circuit. I actually have such a circuit built, and I took some measurements today. I'll wind a 1.8uH inductor on a T37-2 tonight and compare. Thanks to all for the responses. -- Ben Jackson AD7GD http://www.ben.com/ Article: 97980 of rec.radio.amateur.homebrew From: John Navas Subject: Re: How to calculate increase of home wireless router range? Message-ID: References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <4hg2viF1r60boU1@individual.net> Date: Mon, 10 Jul 2006 23:51:19 GMT On Tue, 11 Jul 2006 08:34:24 +1000, "Rod Speed" wrote in <4hg2viF1r60boU1@individual.net>: >Invalid@charter.net wrote >> John - KD5YI wrote >>> Rod Speed wrote >>>> Geoffrey S. Mendelson wrote >>>>> Rod Speed wrote > >>>>>>> Is one transmit and the other receive? >>>>>>> Or are they both transmit and receive? > >>>>>> They're normally both transmit and receive. > >>>>> That's a shame. Here in Israel we are limited to >>>>> 100mw EIRP, which severly limits the transmit >>>>> antenna. There is NO limitation on the receive antenna. > >>>> A receive antenna has no EIRP, it doesnt radiate any real power. > >>> Actually, when properly matched, it radiates half the received power. > >> True, but it's such a low level as to normally be considered insignificant. > >Which is what I said in different words. > >> Unfortunately some take that to mean there is none. > >The word REAL was used for a reason. > >> If there were none, a Yagi antenna which used all passive >> elements save for the driven element would not work. On >> receive that driven element plays an active (pardon the pun) roll. > >Having fun thrashing that straw man are you ? Take a deep breath. He was more or less on your side. Not nice to lash out at him too (or anyone for that matter). -- Best regards, FAQ for Wireless Internet: John Navas FAQ for Wi-Fi: Wi-Fi How To: Fixes to Wi-Fi Problems: Article: 97981 of rec.radio.amateur.homebrew From: "Don K" References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> Subject: Re: How to calculate increase of home wireless router range? Date: Mon, 10 Jul 2006 19:51:42 -0400 Message-ID: wrote in message news:doj5b29m0puk3fm9jtj8k02uv5ppktaa24@4ax.com... > On Sat, 08 Jul 2006 16:08:23 GMT, John - KD5YI > wrote: >> >>Actually, when properly matched, it radiates half the received power. > > True, but it's such a low level as to normally be considered > insignificant. Unfortunately some take that to mean there is none. > > If there were none, a Yagi antenna which used all passive elements > save for the driven element would not work. On receive that driven > element plays an active (pardon the pun) roll. Still, that's a special case. I can choose a different special case with a different result. For a large, high-gain aperture-type antenna such as a big horn or dish, virtually the received energy orthogonally incident on its cross-section will be sucked up and absorbed. Therefore you can't really say that an antenna always radiates at least half the received power. Don Article: 97982 of rec.radio.amateur.homebrew From: John Navas Subject: Re: How to calculate increase of home wireless router range? Message-ID: <80q5b2ham4td8qh78hvsal8mugijqivknn@4ax.com> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <6_xqg.86010$uP.64508@newsfe2-gui.ntli.net> <11of8oney2ztt.1rzsok8gvo9mf.dlg@40tude.net> Date: Mon, 10 Jul 2006 23:54:49 GMT On Mon, 10 Jul 2006 18:24:27 -0400, Invalid@charter.net wrote in : >On Tue, 4 Jul 2006 21:31:06 +0000 (UTC), gsm@mendelson.com (Geoffrey >S. Mendelson) wrote: >>Make sure to use encryption. Encryption is NOT to keep your data safe, >>nothing can do that. If someone is intent on accessing your network, WEP >>encryption will not keep them out. > >True, but the ones that use the dynamic encryption can do a reasonably >good job along with a firewall and router. The golden rule is >"Nothing is bullet proof" Not even in the same universe -- WEP is easily cracked in minutes, little more than the Emperor's new clothes. Use WPA with a strong passphrase for any real security. >One of the locals mentioned doing a bit of "war driving" around town >just for curiosity. About 80 to 90% of the networks heard were >unencrypted AND over half of those _still_used_ >the_default_name_and_PW. Yep ... really bad ... shame on the wireless hardware companies! >I use hard wired Cat5e in a gigabit network as with the amount of >traffic wireless is just too slow even if it is full duplex. Wi-Fi is half duplex. -- Best regards, FAQ for Wireless Internet: John Navas FAQ for Wi-Fi: Wi-Fi How To: Fixes to Wi-Fi Problems: Article: 97983 of rec.radio.amateur.homebrew Date: Mon, 10 Jul 2006 21:32:35 -0400 From: VOA SWLer Subject: Sept 9+10 - ARRL MDC Section Convention Message-ID: Click on: for info. Article: 97984 of rec.radio.amateur.homebrew From: "Rod Speed" Subject: Re: How to calculate increase of home wireless router range? Date: Tue, 11 Jul 2006 11:35:37 +1000 Message-ID: <4hgdjbF1rbknvU1@individual.net> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <4hg2viF1r60boU1@individual.net> John Navas wrote > Rod Speed wrote >> Invalid@charter.net wrote >>> John - KD5YI wrote >>>> Rod Speed wrote >>>>> Geoffrey S. Mendelson wrote >>>>>> Rod Speed wrote >>>>>>>> Is one transmit and the other receive? >>>>>>>> Or are they both transmit and receive? >>>>>>> They're normally both transmit and receive. >>>>>> That's a shame. Here in Israel we are limited to >>>>>> 100mw EIRP, which severly limits the transmit >>>>>> antenna. There is NO limitation on the receive antenna. >>>>> A receive antenna has no EIRP, it doesnt radiate any real power. >>>> Actually, when properly matched, it radiates half the received power. >>> True, but it's such a low level as to normally be considered insignificant. >> Which is what I said in different words. >>> Unfortunately some take that to mean there is none. >> The word REAL was used for a reason. >>> If there were none, a Yagi antenna which used all passive >>> elements save for the driven element would not work. On >>> receive that driven element plays an active (pardon the pun) roll. >> Having fun thrashing that straw man are you ? > Take a deep breath. Get stuffed. > He was more or less on your side. Duh. > Not nice to lash out at him too You wouldnt know what a lash was if it was applied to your lard arse. > (or anyone for that matter). You get no say what so ever on whose arse gets lashed either. Article: 97985 of rec.radio.amateur.homebrew From: John Navas Subject: Re: How to calculate increase of home wireless router range? Message-ID: References: <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <4hg2viF1r60boU1@individual.net> <4hgdjbF1rbknvU1@individual.net> Date: Tue, 11 Jul 2006 01:37:37 GMT On Tue, 11 Jul 2006 11:35:37 +1000, "Rod Speed" wrote in <4hgdjbF1rbknvU1@individual.net>: >[SNIP] *plonk* -- Best regards, FAQ for Wireless Internet: John Navas FAQ for Wi-Fi: Wi-Fi How To: Fixes to Wi-Fi Problems: Article: 97986 of rec.radio.amateur.homebrew From: "Joel Kolstad" Subject: Re: What is a wire antenna's impedance? Date: Mon, 10 Jul 2006 19:57:03 -0700 Message-ID: <12b64rut80ida99@corp.supernews.com> References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> <1152463076.490252.133390@b28g2000cwb.googlegroups.com> <96bsg.3011$pB.2982@trnddc06> "John - KD5YI" wrote in message news:96bsg.3011$pB.2982@trnddc06... > jo9s8as@yahoo.com wrote: > Output power has nothing to do with antenna impedance. At least until the antenna starts to melt. :-) I have a suspicion that many of the "random wire" antennas you see on something like his video transmitter are actually roughly lambda/2 ("end-fed zepps") -- seems to me their impedance wouldn't be as sensitive to the exact positioning relative to the case, his hands, etc., and that the higher impedance is often easier to match to for a low-power transmitter anyway. Article: 97987 of rec.radio.amateur.homebrew From: "Oscar Jones" References: <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> <4hg2viF1r60boU1@individual.net> <4hgdjbF1rbknvU1@individual.net> Subject: Re: How to calculate increase of home wireless router range? Date: Tue, 11 Jul 2006 13:09:28 +1000 Message-ID: <44b31668$0$17541$61c65585@un-2park-reader-01.sydney.pipenetworks.com.au> John Navas wrote: > On Tue, 11 Jul 2006 11:35:37 +1000, "Rod Speed" > wrote in <4hgdjbF1rbknvU1@individual.net>: > >> [SNIP] > > *plonk* Fat lot of good that will do you, you stupid plonker. Article: 97988 of rec.radio.amateur.homebrew From: John - KD5YI Subject: Re: What is a wire antenna's impedance? References: <1152300593.974477.241010@35g2000cwc.googlegroups.com> <1152463076.490252.133390@b28g2000cwb.googlegroups.com> <96bsg.3011$pB.2982@trnddc06> <12b64rut80ida99@corp.supernews.com> Message-ID: Date: Tue, 11 Jul 2006 04:43:02 GMT Joel Kolstad wrote: > "John - KD5YI" wrote in message > news:96bsg.3011$pB.2982@trnddc06... > >>jo9s8as@yahoo.com wrote: >>Output power has nothing to do with antenna impedance. > > > At least until the antenna starts to melt. :-) > > I have a suspicion that many of the "random wire" antennas you see on > something like his video transmitter are actually roughly lambda/2 ("end-fed > zepps") -- seems to me their impedance wouldn't be as sensitive to the exact > positioning relative to the case, his hands, etc., and that the higher > impedance is often easier to match to for a low-power transmitter anyway. > There was an article on 1/2 wave whips for handhelds a few months ago in QEX. The author did quite a bit of experimentation, as I recall, and specifically made a hand-held metal box on which to mount the antenna so that his body, hands, etc would be included in his measurements. I remember his comment about how far away from his mouth he held the box and antenna to make his measurements. But, I don't know how this would compare with a 1/4 wave whip for sensitivities. It is interesting to insert a 1/4 wave whip into an MFJ269, walk around, and watch the readings. Article: 97989 of rec.radio.amateur.homebrew From: Ben Jackson Subject: Re: Toroid or molded inductor in low voltage tank? References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> Message-ID: Date: Mon, 10 Jul 2006 23:54:52 -0500 On 2006-07-10, Ben Jackson wrote: > > I actually have such a circuit built, and I took some measurements > today. I'll wind a 1.8uH inductor on a T37-2 tonight and compare. Ok, I wound 20 turns of about 30ga wire on a T30-2 and compared before/ after (each with the trim cap set for peak) and it's about 2.75V p-p vs 2.0V p-p, or ~3dB. I'll put it on the spectrum analyzer at work again to make sure the unwanted products are still in the same place, but it looks like a win for high Q. Thanks to everyone who replied, it was very educational! Anyone have any tips for securing fine-wire toroids in Ugly/Manhattan construction? :) -- Ben Jackson AD7GD http://www.ben.com/ Article: 97990 of rec.radio.amateur.homebrew From: Paul Keinanen Subject: Re: How to calculate increase of home wireless router range? Message-ID: <07e6b2tnk25h4fl6c25lmlscqd3m4foan4@4ax.com> References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <12ak2k0hqa77dae@corp.supernews.com> <1sr34qtndtz8m.8y1znh8b5w9o$.dlg@40tude.net> <1i8d1tcl66zdn$.7knr5ebizk69.dlg@40tude.net> <4gvpb5F1oatv7U1@individual.net> <4h089vF1pk0rnU1@individual.net> Date: Tue, 11 Jul 2006 08:59:52 +0300 On Mon, 10 Jul 2006 18:11:13 -0400, Invalid@charter.net wrote: >If there were none, a Yagi antenna which used all passive elements >save for the driven element would not work. On receive that driven >element plays an active (pardon the pun) roll. The driven elements should be resonant and connected to a matched load, while the parasitic elements are off-resonance and not connected to a matched load, but they are just grounded to the (virtual) boom. Thus, it is quite natural, that the parasitic elements will reradiate any energy from the passing field and hopefully the reradiation from all parasitic elements arrive in correct phase to the driven element, to form the desired radiation pattern. Paul Article: 97991 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Toroid or molded inductor in low voltage tank? Date: Tue, 11 Jul 2006 00:29:05 -0700 Message-ID: <12b6kq2b9cp1uef@corp.supernews.com> References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> Ben Jackson wrote: > . . . > Anyone have any tips for securing fine-wire toroids in > Ugly/Manhattan construction? :) A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or a couple of holes in the board and a cable tie. The only thing to avoid is laying it down flat on a solid copper plane. Roy Lewallen, W7EL Article: 97992 of rec.radio.amateur.homebrew Date: Tue, 11 Jul 2006 10:53:18 +0100 From: Highland Ham Subject: Re: How to calculate increase of home wireless router range? References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <6_xqg.86010$uP.64508@newsfe2-gui.ntli.net> <11of8oney2ztt.1rzsok8gvo9mf.dlg@40tude.net> <80q5b2ham4td8qh78hvsal8mugijqivknn@4ax.com> Message-ID: >> One of the locals mentioned doing a bit of "war driving" around town >> just for curiosity. About 80 to 90% of the networks heard were >> unencrypted AND over half of those _still_used_ >> the_default_name_and_PW. > > Yep ... really bad ... shame on the wireless hardware companies! ======================== You probably mean 'shame on the users' who haven't got a clue. By the way it is the same situation here in the north of Scotland . Driving in Inverness you can freely access WiFi points allover town ,from commercial companies to hotels..........but not at locations where you would expect it ....like 'Starbuck' and bookshops like 'Borders' Also in California you have to pay for WiFi access at Starbuck.........must constitute a increasing part of their income,considering the number of people with laptops.....usually without a coffee.. I know ,I know ...life isn't a freebee Frank GM0CSZ / KN6WH Article: 97993 of rec.radio.amateur.homebrew From: gsm@mendelson.com (Geoffrey S. Mendelson) Subject: Re: How to calculate increase of home wireless router range? Date: Tue, 11 Jul 2006 10:31:03 +0000 (UTC) Message-ID: References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <6_xqg.86010$uP.64508@newsfe2-gui.ntli.net> <11of8oney2ztt.1rzsok8gvo9mf.dlg@40tude.net> <80q5b2ham4td8qh78hvsal8mugijqivknn@4ax.com> Highland Ham wrote: > By the way it is the same situation here in the north of Scotland . > Driving in Inverness you can freely access WiFi points allover town > ,from commercial companies to hotels..........but not at locations where > you would expect it ....like 'Starbuck' and bookshops like 'Borders' This will go on until the Scotish police start doing what the English do. They track traffic at the ISP level looking for "kidde porn". Once they find it, they locate the person sending or receiving the files. They have no trouble getting a warrant and come in and arrest the owner of the account and confiscate their equipment. As soon as they do this, "users" will go looking for unencrypted networks and use them, if they don't know I don't know Scotish law, but in most places the owner of the network is responsible for what is done with it. There was a case in Canada of a man found driving five miles per hour in a residential neighborhood. When the police stopped him, his pants were around his ankles and there was a laptop on his lap. Canada unlike most places has a law prohibiting using other people's internet connections without permission. Most places don't. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson.com N3OWJ/4X1GM IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838 Visit my 'blog at http://geoffstechno.livejournal.com/ Article: 97994 of rec.radio.amateur.homebrew Subject: Re: Toroid or molded inductor in low voltage tank? References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> <12b6kq2b9cp1uef@corp.supernews.com> Message-ID: From: "John Hague" Date: Tue, 11 Jul 2006 13:02:48 +0100 On Tue, 11 Jul 2006 08:29:05 +0100, Roy Lewallen wrote: > Ben Jackson wrote: >> . . . >> Anyone have any tips for securing fine-wire toroids in >> Ugly/Manhattan construction? :) > > A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or a > couple of holes in the board and a cable tie. The only thing to avoid > is laying it down flat on a solid copper plane. > > Roy Lewallen, W7EL Roy Excuse my ignorance, but what is the problem with laying a toroid down on a solid copper plane? I thought the magnetic field was contained within the toroid and thus minimised external effects. I have completed a couple of projects recently with some of the inductors like that and didn't notice any real problem. Mind you, I guess they might have performed better if not mounted that way :o) Best 73 John, G4GOY -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ Article: 97995 of rec.radio.amateur.homebrew From: hikezilla@yahoo.com Subject: Sprint Time Date: 11 Jul 2006 05:28:25 -0700 Message-ID: <1152620905.299015.268010@m73g2000cwd.googlegroups.com> http://www.fpqrp.com/fpqrprun.html Folks, The Flying Pigs Run For The Bacon is Sunday Night! Get ready for some CW QRP sprint fun! To clear up any confusion about the time of the event, the RFTB will ALWAYS be from: 9-11 Eastern time 8-10 Central time 7-9 Mountain time 6-8 Pacific time This is year around, regardless of any daylight savings/standard time changes. Hope to hear you Sunday Night! Article: 97996 of rec.radio.amateur.homebrew From: "Reg Edwards" References: <1152564332.319191.323380@75g2000cwc.googlegroups.com> Subject: Re: Computer alternative to Smith Chart? Date: Tue, 11 Jul 2006 13:40:19 +0100 Message-ID: "AndyS" wrote in message news:1152564332.319191.323380@75g2000cwc.googlegroups.com... > Andy adds: > > I have often used a modified Smith Chart , called an > Impedance/Admittance > chart , to do matching..... If the impedances are not greatly > mismatched, > it is very easy and accurate.... and very very intuitive... > > The ones I used have the impedance cordinates in black and the > admittance coordinates in red..... > > I found them extremly useful in the design of an automated antenna > tuner > which I designed for a Texas Instruments Marine SSB unit, back in the > late 70s..... You could literally track the impedance transormation > mentally > with series and shunt elements..... > > Andy W4OAH ========================================== As an Engineer in my eighties with a long association with transmission lines of all sorts I have never used a Smith Chart, in anger, in the whole of my life. I have always used log tables, sliderules, pocket calculators or, more recently, dedicated computer programs. Use of mathematics gives one a more 'intuitive' insight into how transmission lines work than any chart. But it's a just a matter of opinion and depends on one's basic education. As useful as they were only at HF, Smith Charts became redundent when the personal computer came in. Old habits die hard! ---- Reg. Article: 97997 of rec.radio.amateur.homebrew Message-ID: <44b39e24@maser.urz.unibas.ch> From: Georg Holderied Subject: 2MHz stepup transformer formula ? Date: Tue, 11 Jul 2006 05:49:27 +0000 I need to build a transformer that transforms the output of a signal generator (0.5-2 Mhz 0-20Vpp into 50 ohms) into two opposite phases at 0-250V. Load is a few picofarads and a short length of shielded cable. Where can I find formulas for winding such a transformer ? Is it preferable to build it as an air or on a ferrite core ? What ferrite material would I use ? BTW the signal is used for driving multipole ion traps. I am an electrical engineer but have not much experience with RF. George Article: 97998 of rec.radio.amateur.homebrew From: John Navas Subject: Re: How to calculate increase of home wireless router range? Message-ID: References: <2hqacpnj1nwj$.1683sqqzgbbo2$.dlg@40tude.net> <6_xqg.86010$uP.64508@newsfe2-gui.ntli.net> <11of8oney2ztt.1rzsok8gvo9mf.dlg@40tude.net> <80q5b2ham4td8qh78hvsal8mugijqivknn@4ax.com> Date: Tue, 11 Jul 2006 13:53:52 GMT On Tue, 11 Jul 2006 10:53:18 +0100, Highland Ham wrote in : >>> One of the locals mentioned doing a bit of "war driving" around town >>> just for curiosity. About 80 to 90% of the networks heard were >>> unencrypted AND over half of those _still_used_ >>> the_default_name_and_PW. >> >> Yep ... really bad ... shame on the wireless hardware companies! >======================== >You probably mean 'shame on the users' who haven't got a clue. No, I mean shame on the wireless hardware companies, as I wrote, for such a gross disservice to their customers -- it shouldn't be necessary to be an IT expert to use Wi-Fi safely. It should just work properly. Otherwise it's not ready for the market. -- Best regards, FAQ for Wireless Internet: John Navas FAQ for Wi-Fi: Wi-Fi How To: Fixes to Wi-Fi Problems: Article: 97999 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Toroid or molded inductor in low voltage tank? Message-ID: <4tc7b21hdqakk76ln3keeuri0t0shc2ukr@4ax.com> References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> <12b6kq2b9cp1uef@corp.supernews.com> Date: Tue, 11 Jul 2006 14:21:51 GMT On Tue, 11 Jul 2006 13:02:48 +0100, "John Hague" wrote: >On Tue, 11 Jul 2006 08:29:05 +0100, Roy Lewallen wrote: > >> Ben Jackson wrote: >>> . . . >>> Anyone have any tips for securing fine-wire toroids in >>> Ugly/Manhattan construction? :) >> >> A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or a >> couple of holes in the board and a cable tie. The only thing to avoid >> is laying it down flat on a solid copper plane. >> >> Roy Lewallen, W7EL > >Roy > >Excuse my ignorance, but what is the problem with laying a toroid down on >a solid copper plane? I thought the magnetic field was contained within >the toroid and thus minimised external effects. I have completed a couple >of projects recently with some of the inductors like that and didn't >notice any real problem. Mind you, I guess they might have performed >better if not mounted that way :o) Twofold. One is added capacitance across the windings and secondary is the proximitry of a conductor to the small field around the wire(s) that are not in direct contact with the toroid. Allison > >Best 73 > >John, G4GOY Article: 98000 of rec.radio.amateur.homebrew From: "W3JDR" References: <44b39e24@maser.urz.unibas.ch> Subject: Re: 2MHz stepup transformer formula ? Message-ID: <5aPsg.9750$Ep.2532@trnddc08> Date: Tue, 11 Jul 2006 15:08:49 GMT Georg, If you transform a 20VAC signal from a 50 ohm source into a 250VAC signal, the 250VAC output will be at an impedance of about 7,800 ohms (conservation of energy; Po = Pin). At this high impedance you won't be able to drive virtually any length of coax, even open-circuited, as just a few tens of pF of cable capacitance will cause a significant rolloff at 2 MHz. What load impedance do you intend to drive? BTW, 20Vpp at 50 ohms out of your 'signal generator' is quite a signal - about 1 watt. Is this really the case? Joe W3JDR "Georg Holderied" wrote in message news:44b39e24@maser.urz.unibas.ch... > I need to build a transformer that transforms the output of a signal > generator (0.5-2 Mhz 0-20Vpp into 50 ohms) into two opposite phases > at 0-250V. > > Load is a few picofarads and a short length of shielded cable. > > Where can I find formulas for winding such a transformer ? > > Is it preferable to build it as an air or on a ferrite core ? > > What ferrite material would I use ? > > BTW the signal is used for driving multipole ion traps. > > I am an electrical engineer but have not much experience with RF. > > George > > Article: 98001 of rec.radio.amateur.homebrew From: "Reg Edwards" References: <1152564332.319191.323380@75g2000cwc.googlegroups.com> Subject: Re: Computer alternative to Smith Chart? Date: Tue, 11 Jul 2006 17:28:24 +0100 Message-ID: "Tom Donaly" wrote > > Reg, > have you ever taken the time to learn _how_ to use one? Actually, > they're just as mathematical as the formulas you've always used, and, > for some people, just as useful. ======================================= Yes. Many years ago I attended a lecture. The lecturer handed round Smith Charts as a tutorial. We spent 10 minutes on it. But these days I'm well out of practice. The Smith Chart was only of any use at HF and above. That's what it was invented for. Fine for radio amateurs who only use the HF bands and above. It followed on from previous, more complicated Victorian Age charts to ease calculations involving complex Hyperbolic functions. Very good while it lasted. Small, dedicated computer programs these days are more accurate and time saving than charts and their 'what-if' operating procedures are much more educational. But I appreciate the sentimental attachment, indeed affection, many old timers have for the good old Smith Chart. By all means carry on using them. ---- Reg. Article: 98002 of rec.radio.amateur.homebrew From: Ben Jackson Subject: SA602A oscillator load capacitance Message-ID: Date: Tue, 11 Jul 2006 17:37:55 -0500 I'm trying to figure out the load capacitance of the oscillator pins 6 and 7 on the SA602A. I've got a 14.85MHz fundamental crystal with a specified load capacitance of 13pF running about 1300Hz slow (with 27+22p). The datasheet doesn't say much about the oscillator pins. The best hint I've found is about the SA605: >From AN1994 about the SA605: Because the Colpitts configuration is for parallel resonance mode, it is important to know, when ordering crystals, that the load capacitance of the SA605 is 10pF. That would suggest I'm way, WAY off, and my external load capacitors should only amount to 3p! The SA612A datasheet has an example where it specifies the crystal load capacitance, but then it doesn't specify C1/C2 values. Then it has another example with specific values for C1/C2 (which are 4.5p in series) but does not mention the load capacitance of the 3OT crystal. One at that freq made by CTS has a load capacitance of 13p, which would suggest that the oscillator is about 8.5p. The 602A has a similar example with another unspecified crystal... -- Ben Jackson AD7GD http://www.ben.com/ Article: 98003 of rec.radio.amateur.homebrew From: "Reg Edwards" References: <1152564332.319191.323380@75g2000cwc.googlegroups.com> Subject: Re: Computer alternative to Smith Chart? Date: Tue, 11 Jul 2006 23:36:43 +0100 Message-ID: John Ferrell, W8CCW wrote > I think that is the engineer in you speaking! > > I find the Smith Chart interesting as a tool. I am more interested in > how it works while you are interested in what it is good for! ============================================ John, you've weighed me up fairly well. On the other hand I see much beauty in Mathematics. And program source coding is the labour of love and a Work of Art. But Maths is a much neglected subject in our Western schools and universities these days. Even teachers don't know what five sevens are - and that's only arithmetic. I once asked a prospective Member of Parliament just before a General Election what seven nines are. He didn't know. He lost his £500 deposit. Didn't get enough votes. Otherwise he might have ended up as Chancellor of the Exchequer. ============================================ > My desk drawers still contain a couple of slide rules, a polar > planimeter, a drafting set and a Kurta Calculator. In spite of being > surrounded by an assortment of computers, I keep a good battery in my > HP Calculator and I remain fond of nomograms. ============================================ My Casio scientific calculator must be about 10 years old. I've never changed the battery. ============================================ > The Smith Chart is a tool. I cannot possibly have too many tools... ============================================ I bet you are an amateur carpenter as well. ============================================ > Of course I have archived the programs at g4fgq as well... ============================================ Don't throw away your old computer. Being DOS programs there are ominous signs they won't work too well on new versions of Windows. ============================================ > We could quit teaching Calculus as well, Computers make quick work of > graphic solutions! ============================================ I deliberately avoided graphics. Graphics depend on screen driving software thus losing portability between machines. My favourite Victorian is Oliver Heaviside. He invented the beautiful Operational Calculus which magically transforms ordinary calculus into simple algebra and converts functions of frequency on transmission lines into functions of time. Now everything is going digital at Megabits per second he was about 130 years in advance of his time. All the best to you and yours. ---- Reg, G4FGQ. Article: 98004 of rec.radio.amateur.homebrew From: "W3JDR" References: Subject: Re: SA602A oscillator load capacitance Message-ID: <3KWsg.3642$Th7.2568@trnddc05> Date: Tue, 11 Jul 2006 23:45:03 GMT Ben, When a crystal manufacturer specifies a load capacitance for a crystal, it is usually a good indication that the crystal is meant to operate in the 'parallel resonant' mode. This is a very misleading term however, as the quartz blank only has one pure resonance, and that is a series resonance. However, the equivalent LCR circuit of this series resonant circuit will look like a capacitive or inductive reactance at frequencies removed from the series resonant frequency. At some frequency, the crystal will look inductive enough to resonate an external capacitance of a value specified as the 'load capacitance". Your crystal will will form a parallel resonant circuit at the marked frequency with an external capacitance of 13 pF. This is fairly low, as most crystals are specified for 20-32 pf loads. If your circuit already has too much capacitance, you can lower the net capacitance seen by the crystal by either using a small coupling cap whose value in series with the circuit capacitance equals the load capacitance, or you can put an inductor across the crystal whose value in parallel with the circuit capacitance will result in a net capacitance value equal to the 'load capacitance'. In the former case, the low value of coupling cap could cause an AC voltage drop that might prevent the circuit from oscillating. In the latter case the added inductance could cause a spurious oscillation at an unintended frequency. All things considered in your case, I'd use the series coupling approach. Joe W3JDR "Ben Jackson" wrote in message news:slrneb8a23.1gh6.ben@saturn.home.ben.com... > I'm trying to figure out the load capacitance of the oscillator pins 6 > and 7 on the SA602A. I've got a 14.85MHz fundamental crystal with a > specified load capacitance of 13pF running about 1300Hz slow (with > 27+22p). The datasheet doesn't say much about the oscillator pins. > > The best hint I've found is about the SA605: > > From AN1994 about the SA605: > > Because the Colpitts configuration is for parallel resonance > mode, it is important to know, when ordering crystals, that > the load capacitance of the SA605 is 10pF. > > That would suggest I'm way, WAY off, and my external load capacitors > should only amount to 3p! > > The SA612A datasheet has an example where it specifies the crystal load > capacitance, but then it doesn't specify C1/C2 values. Then it has > another example with specific values for C1/C2 (which are 4.5p in series) > but does not mention the load capacitance of the 3OT crystal. One at > that freq made by CTS has a load capacitance of 13p, which would suggest > that the oscillator is about 8.5p. The 602A has a similar example with > another unspecified crystal... > > -- > Ben Jackson AD7GD > > http://www.ben.com/ Article: 98005 of rec.radio.amateur.homebrew From: "K7ITM" Subject: Re: 2MHz stepup transformer formula ? Date: 11 Jul 2006 17:20:16 -0700 Message-ID: <1152663616.663886.100710@p79g2000cwp.googlegroups.com> References: <44b39e24@maser.urz.unibas.ch> I've had some experience driving quadrupole ion filters... I would guess you would do best with a high Q tank circuit driving the ion trap through as short a length of wire as possible. Keep the tank and the wiring very well balanced with respect to stray capacitance to ground, especially. You can use a link to couple RF energy into the tank circuit. The capacitance of the trap is probably enough to resonate the tank coil. You can split the coil into two halves, with the "hot" end of each half going to the ion trap, and the "cold" ends connected together with a bypass capacitor; then you can apply DC across that bypass capacitor, and the DC will be carried directly to the ion trap. I am assuming here that you want to drive your trap in the normal way, with a combination of RF and DC. It is usual to use feedback to maintain an accurate RF voltage. You can add small capacitors, one from each "hot" lead to the trap, back to a rectifier with low input impedance. The capacitor impedance then sets the voltage to current conversion ratio, and will be frequency dependent of course. If you use a resonant tank circuit with a loaded Q (nearly equal to the unloaded Q) of, say, 250, and you have net capacitance (ion trap plus wiring plus coil plus voltage sampling capacitors) of, say, 32pF, and the operating frequency is 1MHz, then the tank impedance across the trap will be about 250*5k, or 1.25megohms. At 500V RMS, that's only 0.2 watts. It appears that your signal generator can put out 1 watt, so it's quite possible that your signal generator can drive the tank without an amplifier. You can experiment with links (one turn, or a very few turns, over the area of the tank where it is split in two) to see what gives best results. You can vary the coupling by adding a variable capacitor in series with the link to the generator. Proper adjustment will give you a 50 ohm load for the generator, at the tank's resonant frequency. Winding a modest size tank coil with such a high Q at 1MHz is not trivial, but certainly possible. With such a resonant tank circuit, which is useful both in getting high voltage and in reducing harmonics in the drive, it will be difficult to operate over such a wide frequency range. Do you really need to do that? If you do, I would advise you to add a medium-power amplifier between the signal generator and the step-up transformer, and beware about a lack of harmonic filtering as a result of your broad-band circuit. Further details about exactly what you are trying to accomplish might be helpful. Cheers, Tom Georg Holderied wrote: > I need to build a transformer that transforms the output of a signal > generator (0.5-2 Mhz 0-20Vpp into 50 ohms) into two opposite phases > at 0-250V. > > Load is a few picofarads and a short length of shielded cable. > > Where can I find formulas for winding such a transformer ? > > Is it preferable to build it as an air or on a ferrite core ? > > What ferrite material would I use ? > > BTW the signal is used for driving multipole ion traps. > > I am an electrical engineer but have not much experience with RF. > > George Article: 98006 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Toroid or molded inductor in low voltage tank? Date: Tue, 11 Jul 2006 18:35:26 -0700 Message-ID: <12b8kevkvh4qi33@corp.supernews.com> References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> <12b6kq2b9cp1uef@corp.supernews.com> John Hague wrote: > On Tue, 11 Jul 2006 08:29:05 +0100, Roy Lewallen wrote: > >> Ben Jackson wrote: >>> . . . >>> Anyone have any tips for securing fine-wire toroids in >>> Ugly/Manhattan construction? :) >> >> A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or >> a couple of holes in the board and a cable tie. The only thing to >> avoid is laying it down flat on a solid copper plane. >> >> Roy Lewallen, W7EL > > Roy > > Excuse my ignorance, but what is the problem with laying a toroid down > on a solid copper plane? I thought the magnetic field was contained > within the toroid and thus minimised external effects. I have completed > a couple of projects recently with some of the inductors like that and > didn't notice any real problem. Mind you, I guess they might have > performed better if not mounted that way :o) Two potential problems. One is that the field isn't completely contained. Leakage is greater with more sparsely wound toroids and ones with lower permeability cores. The second is the "one turn effect" - There's a net field equivalent to that of a single turn running circumferentially around the core. A solid plane parallel to this would act as a shorted turn. Both effects would act to lower the Q, and might be the cause of some drift or microphonics if the inductor was in an oscillator tank. But to be honest, I've never run any experiments to see just how much of a problem it might cause -- it's quite possible you could get away with it in some or even most applications. I'll put it on my list of things to do when time permits -- unless somebody else is willing to take on the job. Roy Lewallen, W7EL Article: 98007 of rec.radio.amateur.homebrew From: "Jerry" References: <1151699486.365534.315290@y41g2000cwy.googlegroups.com> Subject: Re: Using Garage for Ham Shack Message-ID: Date: Tue, 11 Jul 2006 22:50:06 -0400 "Alex" wrote in message news:1151699486.365534.315290@y41g2000cwy.googlegroups.com... If you are set on the garage, the insulated door will do wonders. I replaced my old wooden door with plenty of holes and spider access, and it was the best thing I ever did lately!! I can work in the garage with a couple of fans running. It can get cold here in western NC, but in fairness I must mention that my garage and shack is downstairs and partially underground. Another suggestion to consider is one I used in a previous house: a spare closet! I put a desk in the closet with a hutch. There was enough room for all the radios, and when I was thru radio-ing, I could push the chair inside the closet and close the bi-fold doors! No one was the wiser!! People could come visit us in the den and never know there was a fully stocked radio room on the premises! My wife always joked about putting me in the basement, the dog house, or a closet. Now it was TRUE! :) 73 Jerry > Article: 98008 of rec.radio.amateur.homebrew From: bill.meara@gmail.com Subject: Class C amps saturating? Date: 11 Jul 2006 22:58:34 -0700 Message-ID: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> I'm reading David Rutledge's excellent "The Electronics of Radio." In Chapter 10 -- Power Amplifiers, he discusses Class C amps and says, "In addition, if we drive the transistor clear to saturation, using the transistor as a switch, the dissipated power can be greatly reduced, because the saturation voltage is low. This is Class C amplification..." I'd always throught that in Class C, while you'd operate the device so that it was cutoff during most of the cycle, but not saturated. Is this just a different definition of Class C? I checked back with SSDRA and EMRFD, and didn't see anything about driving Class C amps into saturation? What says the group? Do we saturate in Class C or not? 73 from London Bill M0HBR N2CQR CU2JL http://www.gadgeteer.us Article: 98009 of rec.radio.amateur.homebrew Subject: Re: Toroid or molded inductor in low voltage tank? References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> <12b6kq2b9cp1uef@corp.supernews.com> <4tc7b21hdqakk76ln3keeuri0t0shc2ukr@4ax.com> Message-ID: From: "John Hague" Date: Wed, 12 Jul 2006 08:14:13 +0100 On Tue, 11 Jul 2006 15:21:51 +0100, wrote: > On Tue, 11 Jul 2006 13:02:48 +0100, "John Hague" > wrote: > >> On Tue, 11 Jul 2006 08:29:05 +0100, Roy Lewallen wrote: >> >>> Ben Jackson wrote: >>>> . . . >>>> Anyone have any tips for securing fine-wire toroids in >>>> Ugly/Manhattan construction? :) >>> >>> A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or >>> a >>> couple of holes in the board and a cable tie. The only thing to avoid >>> is laying it down flat on a solid copper plane. >>> >>> Roy Lewallen, W7EL >> >> Roy >> >> Excuse my ignorance, but what is the problem with laying a toroid down >> on >> a solid copper plane? I thought the magnetic field was contained within >> the toroid and thus minimised external effects. I have completed a >> couple >> of projects recently with some of the inductors like that and didn't >> notice any real problem. Mind you, I guess they might have performed >> better if not mounted that way :o) > > Twofold. One is added capacitance across the windings and secondary > is the proximitry of a conductor to the small field around the wire(s) > that are not in direct contact with the toroid. > > Allison > > >> >> Best 73 >> >> John, G4GOY > Allison Thanks for the info. I'll watch how I mount my toroids in future. Best 73 John, G4GOY -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ Article: 98010 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Class C amps saturating? Date: Wed, 12 Jul 2006 00:29:26 -0700 Message-ID: <12b996ni52vq167@corp.supernews.com> References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> The Class C transistor amplifiers I design and use most certainly saturate. I believe that's standard practice for solid state amplifiers. I don't think tube type class C amplifiers are or were typically driven to saturation, but I honestly don't know for sure. The classic definition of class C involves only the fraction of the cycle during which it conducts (< 180 degrees). There's no restriction on how hard it conducts. Roy Lewallen, W7EL bill.meara@gmail.com wrote: > I'm reading David Rutledge's excellent "The Electronics of Radio." > > In Chapter 10 -- Power Amplifiers, he discusses Class C amps and says, > "In addition, if we drive the transistor clear to saturation, using the > transistor as a switch, the dissipated power can be greatly reduced, > because the saturation voltage is low. This is Class C > amplification..." > > I'd always throught that in Class C, while you'd operate the device so > that it was cutoff during most of the cycle, but not saturated. > > Is this just a different definition of Class C? > > I checked back with SSDRA and EMRFD, and didn't see anything about > driving Class C amps into saturation? > > What says the group? Do we saturate in Class C or not? > > 73 from London > Bill M0HBR N2CQR CU2JL > http://www.gadgeteer.us > Article: 98011 of rec.radio.amateur.homebrew From: Ben Jackson Subject: Re: Class C amps saturating? References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <12b996ni52vq167@corp.supernews.com> Message-ID: Date: Wed, 12 Jul 2006 02:45:23 -0500 On 2006-07-12, Roy Lewallen wrote: > The Class C transistor amplifiers I design and use most certainly > saturate. I believe that's standard practice for solid state amplifiers. And as a followup, is the power dissipation in the final controlled by the duty cycle of the pulses (or number of degrees of conduction more generally if the input is not a square wave)? -- Ben Jackson AD7GD http://www.ben.com/ Article: 98012 of rec.radio.amateur.homebrew From: "erica" Subject: Low cost SMD Oven for making SMD samples and Prototypes Date: 12 Jul 2006 03:54:52 -0700 Message-ID: <1152701692.603004.306280@35g2000cwc.googlegroups.com> This SMD Oven Controller (SMDOC-01) is designed to use with a toaster oven. It provide a low cost solution for making SMD prototypes and samples. The temperature profile is similar to the expensive industrial SMD oven provided. So, the sample quality is as good as the industrial oven can do. It is capable for packages including 0402, BGA, QFP, SOP, SSOP, TSSOP, SOT, etc. It is an indispensable tool for R&D and making samples. It is very suitable for electronic companies, laboratories, universities and hobbyists. SMD Oven Controller (SMDOC-01) is only US$206, including oven (PCB size is large up to 19 x 17cm) is US$283. Voltage 220V, 8A fused. Features: 1.Small, low price, performance comparable to expensive industrial SMD oven. 2.Capable for any SMD packages. An indispensable tool for R&D, sample making and small batch production. 3.No hand soldering. No painful. No difficult. Save time. 4.Connectable to PC via RS232 for profile setup and temperature monitor. It can also operate independently without PC. 5.Simple to use. LEDs indication for each stage of pre-heat, soak, reflow and cooling. Alarm and power cut off after finished. Product information : http://www.auto-system.com Please send me email : erica@auto-system.com for any inquiry or order. Article: 98013 of rec.radio.amateur.homebrew From: "W3JDR" References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes Message-ID: <505tg.7628$F8.1463@trnddc02> Date: Wed, 12 Jul 2006 11:26:57 GMT There's a much simpler and cheaper solution for experimenter 'one- off' board soldering. Just solder all the part leads to the board without worrying about solder bridging. After you're done, come back and wick off all the excess solder with solder-wick. This will remove all solder bridging, but will leave a good strong solder joint between the part leads and the board pads. Of course it only works on parts with exposed leads, not BGA's etc. Joe W3JDR "erica" wrote in message news:1152701692.603004.306280@35g2000cwc.googlegroups.com... > This SMD Oven Controller (SMDOC-01) is designed to use with a toaster > oven. It provide a low cost solution for making SMD prototypes and > samples. The temperature profile is similar to the expensive industrial > SMD oven provided. So, the sample quality is as good as the industrial > oven can do. It is capable for packages including 0402, BGA, QFP, SOP, > SSOP, TSSOP, SOT, etc. It is an indispensable tool for R&D and making > samples. It is very suitable for electronic companies, laboratories, > universities and hobbyists. SMD Oven Controller (SMDOC-01) is only > US$206, including oven (PCB size is large up to 19 x 17cm) is US$283. > Voltage 220V, 8A fused. > > Features: > 1.Small, low price, performance comparable to expensive industrial SMD > oven. > 2.Capable for any SMD packages. An indispensable tool for R&D, sample > making and small batch production. > 3.No hand soldering. No painful. No difficult. Save time. > 4.Connectable to PC via RS232 for profile setup and temperature > monitor. It can also operate independently without PC. > 5.Simple to use. LEDs indication for each stage of pre-heat, soak, > reflow and cooling. Alarm and power cut off after finished. > > > Product information : http://www.auto-system.com > Please send me email : erica@auto-system.com for any inquiry or order. > Article: 98014 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Toroid or molded inductor in low voltage tank? Message-ID: References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> <12b6kq2b9cp1uef@corp.supernews.com> <12b8kevkvh4qi33@corp.supernews.com> Date: Wed, 12 Jul 2006 11:52:34 GMT On Tue, 11 Jul 2006 18:35:26 -0700, Roy Lewallen wrote: >John Hague wrote: >> On Tue, 11 Jul 2006 08:29:05 +0100, Roy Lewallen wrote: >> >>> Ben Jackson wrote: >>>> . . . >>>> Anyone have any tips for securing fine-wire toroids in >>>> Ugly/Manhattan construction? :) >>> >>> A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or >>> a couple of holes in the board and a cable tie. The only thing to >>> avoid is laying it down flat on a solid copper plane. >>> >>> Roy Lewallen, W7EL >> >> Roy >> >> Excuse my ignorance, but what is the problem with laying a toroid down >> on a solid copper plane? I thought the magnetic field was contained >> within the toroid and thus minimised external effects. I have completed >> a couple of projects recently with some of the inductors like that and >> didn't notice any real problem. Mind you, I guess they might have >> performed better if not mounted that way :o) > >Two potential problems. One is that the field isn't completely >contained. Leakage is greater with more sparsely wound toroids and ones >with lower permeability cores. The second is the "one turn effect" - >There's a net field equivalent to that of a single turn running >circumferentially around the core. A solid plane parallel to this would >act as a shorted turn. Both effects would act to lower the Q, and might >be the cause of some drift or microphonics if the inductor was in an >oscillator tank. > >But to be honest, I've never run any experiments to see just how much of >a problem it might cause -- it's quite possible you could get away with >it in some or even most applications. I'll put it on my list of things >to do when time permits -- unless somebody else is willing to take on >the job. > >Roy Lewallen, W7EL I've not tested for Q degradation but the added capacitance and chance for movement makes VFOs far more unstable. Microphonics from movement are part of the problem but if glue is used that goes away and the stability of the glue with temperature is then an issue. The single turn field while small is likely related to the number of turns and with fewer turns I'd think even a modest distance such as 0.1" it would not be a significant factor. Allison Article: 98015 of rec.radio.amateur.homebrew From: "Tim Shoppa" Subject: Re: Class C amps saturating? Date: 12 Jul 2006 06:58:36 -0700 Message-ID: <1152712716.004638.184560@m73g2000cwd.googlegroups.com> References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> bill.meara@gmail.com wrote: > I'm reading David Rutledge's excellent "The Electronics of Radio." > > In Chapter 10 -- Power Amplifiers, he discusses Class C amps and says, > "In addition, if we drive the transistor clear to saturation, using the > transistor as a switch, the dissipated power can be greatly reduced, > because the saturation voltage is low. This is Class C > amplification..." > > I'd always throught that in Class C, while you'd operate the device so > that it was cutoff during most of the cycle, but not saturated. > > Is this just a different definition of Class C? > > I checked back with SSDRA and EMRFD, and didn't see anything about > driving Class C amps into saturation? > > What says the group? Do we saturate in Class C or not? Saturation is itself a somewhat mushy point. There's a V_sat specified on the datasheets but the actual definition of saturated is entirely application-sensitive. As a practical matter as you add more base current you will go further into saturation (up until you melt the base-emitter junction and then all sorts of wacky things ensue). Choice of drive level and output level and load impedance in a Class C amplifier certainly will in many cases put the device into saturation. Tim. Article: 98016 of rec.radio.amateur.homebrew From: Xor Subject: Re: Toroid or molded inductor in low voltage tank? Date: Wed, 12 Jul 2006 14:45:22 -0000 Message-ID: <12ba2o2mhmg92dc@corp.supernews.com> References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> <12b6kq2b9cp1uef@corp.supernews.com> <12b8kevkvh4qi33@corp.supernews.com> Roy Lewallen wrote: > > John Hague wrote: > > On Tue, 11 Jul 2006 08:29:05 +0100, Roy Lewallen wrote: > > > >> Ben Jackson wrote: > >>> . . . > >>> Anyone have any tips for securing fine-wire toroids in > >>> Ugly/Manhattan construction? :) > >> > >> A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or > >> a couple of holes in the board and a cable tie. The only thing to > >> avoid is laying it down flat on a solid copper plane. > >> > >> Roy Lewallen, W7EL > > > > Roy > > > > Excuse my ignorance, but what is the problem with laying a toroid down > > on a solid copper plane? I thought the magnetic field was contained > > within the toroid and thus minimised external effects. I have completed > > a couple of projects recently with some of the inductors like that and > > didn't notice any real problem. Mind you, I guess they might have > > performed better if not mounted that way :o) > > Two potential problems. One is that the field isn't completely > contained. Leakage is greater with more sparsely wound toroids and ones > with lower permeability cores. The second is the "one turn effect" - > There's a net field equivalent to that of a single turn running > circumferentially around the core. A solid plane parallel to this would > act as a shorted turn. Both effects would act to lower the Q, and might > be the cause of some drift or microphonics if the inductor was in an > oscillator tank. > > But to be honest, I've never run any experiments to see just how much of > a problem it might cause -- it's quite possible you could get away with > it in some or even most applications. I'll put it on my list of things > to do when time permits -- unless somebody else is willing to take on > the job. > > Roy Lewallen, W7EL "One turn effect" in magnetic core computer memory? Miniature toroids single-stitched and woven with wire: http://www.fortunecity.com/marina/reach/435/coremem.htm What's the Amidon number of these cores? Some electric guitar tube amps used perpendicular point-to-point wiring in 3-dimensions between terminal strips to minimize inductive and capactive crosstalk. They are amazing to see. -- LIGO: World's largest SWR meter or the world's most expensive grid dip meter?: http://www.nytimes.com/2006/05/02/science/space/02hole.html Article: 98017 of rec.radio.amateur.homebrew From: "Tim Shoppa" Subject: Re: Class C amps saturating? Date: 12 Jul 2006 08:00:09 -0700 Message-ID: <1152716409.640559.299070@35g2000cwc.googlegroups.com> References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> Ben Jackson wrote: > On 2006-07-12, Roy Lewallen wrote: > > The Class C transistor amplifiers I design and use most certainly > > saturate. I believe that's standard practice for solid state amplifiers. > > And as a followup, is the power dissipation in the final controlled > by the duty cycle of the pulses (or number of degrees of conduction > more generally if the input is not a square wave)? For operation at HF and higher, it's not always that simple. For anything but the lowest-speed PWM/class C/class D/class E operations, the transistor switching time (and the influence of the load on the switching time) can be a most important contributor to power dissipated in the device. An indication of the "bare transistor" switching time can be found on the datasheets as the delay time, rise time, and most importantly storage time and fall time. Very closely related if you are operating anywhere near max power dissipation or max current is the SOA curve. Tim. Article: 98018 of rec.radio.amateur.homebrew From: "ars_wa8mea@netzero.com" Subject: Surplus Sales of Nebraska Date: 12 Jul 2006 08:19:19 -0700 Message-ID: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> I, like many hams, have gotten a lot of surplus stuff from Fair Radio Sales in Ohio. Monday, I discovered Surplus Sales of Nebraska. Nice people! Old school customer service. The web ordering isn't "modern". But they don't make a lot of money at this, I'm sure. So I.T. people are probably out of the question. But your order gets underway in about 48 hours..... They told me the owner spends all day on the net trying to hunt down surplus stuff he can buy. So if you have anything, I was told to take a photo of it....and send an e-mail to him. His e-mail address is at the bottom of every web page. Here's the website for Surplus Sales: http://www.surplussales.com/ 73, Bill - WA8MEA ars_wa8mea@netsero.com http://HamRadioFun.com Article: 98019 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Toroid or molded inductor in low voltage tank? Message-ID: References: <1152570434.601377.304290@35g2000cwc.googlegroups.com> <12b6kq2b9cp1uef@corp.supernews.com> <12b8kevkvh4qi33@corp.supernews.com> <12ba2o2mhmg92dc@corp.supernews.com> Date: Wed, 12 Jul 2006 15:24:38 GMT On Wed, 12 Jul 2006 14:45:22 -0000, Xor wrote: > >"One turn effect" in magnetic core computer memory? >Miniature toroids single-stitched and woven with wire: > http://www.fortunecity.com/marina/reach/435/coremem.htm >What's the Amidon number of these cores? Different animal. Those cores have a high remnent magnetism and a very hard BH curve. The initial ui is far higher than common ferrites used in RF today. Some were nickel based steels in very thin foils wound as 50-200mil toroids. The idea is you write them with a lot of current (for a 50mil core around 2-300ma) and read them by "writing" them with an apposing polarity pulse, the size and timing of the pulse returned is a 0 or 1 after amplification and slicing. The key is you always get a pulse during read but it's about 3-5x bigger and delayed in time (25 to 300ns depending on core size, temperature and material) _if_ the core was written in with the opposing magnetic polarity. Typical cores such as used in DEC pdp-8E had a memory cycle time of 1.6uS (read, modify, write) as a read is destructive and requires a write cycle to restore the data. That was typical speed for core memory of the day (1970). If you want to try this for yourself (1bit memory) a nail or better a peice of hypersil (transformer core material) with a few turns of wire, compass and a scope will demonstrate it. The test will be to find how much DC current will magnetize it then find out how much it takes to reverse the magnetism (compass helps here). Then you add a few turn sense winding and watch the pulse that results when you magnetize it with a given polarity, repeatedly. Then reverse the power and hit it and the resulting pulse will be later in time and bigger. >Some electric guitar tube amps used perpendicular >point-to-point wiring in 3-dimensions between >terminal strips to minimize inductive and capactive >crosstalk. They are amazing to see. Different animal, thats called cordwood construction and its also for space savings and affords mechanical ruggedness. Early aerospace systems were built that way for size. Problem is they are impossible to maintain and heat is problematic for larger cordwood. Neither directly relate to the concept of an tuned toroid inductor in proxmetry to other conductors/metal cases/ inductors. Allison Article: 98020 of rec.radio.amateur.homebrew Message-ID: <44B51485.F82FB5A@nospamforme.net> From: gary Subject: Re: Surplus Sales of Nebraska References: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> Date: Wed, 12 Jul 2006 15:25:59 GMT hi bill, yes, they have a lot of stuff to check out at the website, they upgraded it a year or two ago, lots of good photos. I get my tubes from them, go to tube specials, 12by7a and 6146W JAN circa 1985 by GE. 73 gary Article: 98021 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Class C amps saturating? Date: Wed, 12 Jul 2006 08:34:19 -0700 Message-ID: <12ba5jt7mjmr5b7@corp.supernews.com> References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <12b996ni52vq167@corp.supernews.com> Ben Jackson wrote: > On 2006-07-12, Roy Lewallen wrote: >> The Class C transistor amplifiers I design and use most certainly >> saturate. I believe that's standard practice for solid state amplifiers. > > And as a followup, is the power dissipation in the final controlled > by the duty cycle of the pulses (or number of degrees of conduction > more generally if the input is not a square wave)? Not really, although it's a factor. What counts more is the transistor voltage when the current is maximum, and the relationship between V and I during switching. This in turn depends on the nature of the output network among other things. If you really want to find out more about the efficiency of a saturating transistor amplifier, look up some of the papers on "class E" operation by Sokal & Sokal and by Raab. They basically took a time-domain approach to find the optimum conditions for maximum efficiency of a saturating class C amplifier. I've never consciously designed a "class E" amplifier, but have gotten more than 85% collector efficiency from saturating Class C amplifiers at the 10 watt input level. Roy Lewallen, W7EL Article: 98022 of rec.radio.amateur.homebrew From: Bill Turner Subject: Re: Surplus Sales of Nebraska Date: Wed, 12 Jul 2006 09:53:19 -0700 Message-ID: <6v9ab21u7i8ss7k07fs47k70emppedh703@4ax.com> References: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> ORIGINAL MESSAGE: On 12 Jul 2006 08:19:19 -0700, "ars_wa8mea@netzero.com" wrote: >Nice people! Old school customer service. The web ordering isn't >"modern". But they don't make a lot of money at this, I'm sure. So >I.T. people are probably out of the question. But your order gets >underway in about 48 hours..... ------------ REPLY SEPARATOR ------------ Bull. SS of N is one place I will never buy from again. They do not remove out-of-stock items from their website when sold out, but they continue to take orders for them. In a couple of days, they notify you the item is no longer in stock, thereby wasting your time you could have spent looking elsewhere. This has happened to me several times. Actual phone conversation: Me: Can you check stock on part number xxxx? Them: No. No explanation, no "sorry", nothing but "no". These are not my kind of people. Bill, W6WRT Article: 98023 of rec.radio.amateur.homebrew From: et472@FreeNet.Carleton.CA (Michael Black) Subject: Re: Surplus Sales of Nebraska Date: 12 Jul 2006 17:41:53 GMT Message-ID: References: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> <6v9ab21u7i8ss7k07fs47k70emppedh703@4ax.com> Bill Turner (noway@nohow.com) writes: > ORIGINAL MESSAGE: > > On 12 Jul 2006 08:19:19 -0700, "ars_wa8mea@netzero.com" > wrote: > >>Nice people! Old school customer service. The web ordering isn't >>"modern". But they don't make a lot of money at this, I'm sure. So >>I.T. people are probably out of the question. But your order gets >>underway in about 48 hours..... > > ------------ REPLY SEPARATOR ------------ > > Bull. SS of N is one place I will never buy from again. They do not > remove out-of-stock items from their website when sold out, but they > continue to take orders for them. In a couple of days, they notify you > the item is no longer in stock, thereby wasting your time you could > have spent looking elsewhere. This has happened to me several times. > > Actual phone conversation: > > Me: Can you check stock on part number xxxx? > Them: No. > > No explanation, no "sorry", nothing but "no". These are not my kind of > people. > > Bill, W6WRT I find it odd that the original poster felt a need to post about the company to three different newsgroups (likely bad enough that he felt the need, made worse by doing multiple posting), especially given that the company has been around for decades. I remember when I first saw an ad for the company years ago, and thought "wow". But when I got a catalog, I felt the prices were outrageous. Maybe if you want to rebuild a KWM-2 to out of the box standards you're willing to pay large prices for the exact knob, but as a surplus outlet I felt there were better prices elsewhere. Because when you see the word "surplus", you immediately think of low prices compared to new stock. Michael VE2BVW Article: 98024 of rec.radio.amateur.homebrew From: Satoru Uzawa Subject: Re: 2SC2397 Datasheet ? Date: Wed, 12 Jul 2006 17:55:38 +0000 (UTC) Message-ID: References: <1149332944.772826.5820@h76g2000cwa.googlegroups.com> <4ed9jjF1dr180U1@individual.net> <4edea7F1edbd3U1@individual.net> <2823829uu6kp759v8jkbsgh6s1f5m3fhq3@4ax.com> Sphero, The way Japanese read Chinese chracters is done in two ways. 1. Something resembles the original Chinese pronounciation at the time Like Hitachi's "Hi" part. 2. Ancient Japanese word adopted to a Chinese chracter with same meaning. Like Hitachi's "Tachi" part. This means "standing", as you mentioned. Hitachi is the name of the city where Hitachi originated as a repair facility for the mine there in 1910. Mazda is actually "Matsuda", which is composed of "Matsu (pine tree)" and "Ta (field)". "Ta" changes to "Da" when it is attached to some other character (sorry, forgot how is called in English). "Matsu" and "Ta" are both from ancient Japanese words. Alps is named after the English term "Alps". Hope I'm not confusing you even more! Regards, Satoru > BTW, any Japanese speakers here? The Japanese characters for Hitachi > appear to be only two syllables. The characters would be pronounced > "ri4 li4" in Chinese ('sun' or 'day' and 'stand'), maybe "hi ta" in > Japanese? Is the "chi" just tacked on in English? > > Mazda is the opposite-- it's three syllables in Chinese (and probably > Japanese as well). And Alps (the component maker)is two syllables in > Japanese. > > > Best regards, > Spehro Pefhany Article: 98025 of rec.radio.amateur.homebrew From: "Tim Shoppa" Subject: Re: Surplus Sales of Nebraska Date: 12 Jul 2006 11:26:00 -0700 Message-ID: <1152728760.128333.118180@h48g2000cwc.googlegroups.com> References: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> Bill Turner wrote: > Bull. SS of N is one place I will never buy from again. They do not > remove out-of-stock items from their website when sold out, but they > continue to take orders for them. In a couple of days, they notify you > the item is no longer in stock, thereby wasting your time you could > have spent looking elsewhere. This has happened to me several times. > > Actual phone conversation: > > Me: Can you check stock on part number xxxx? > Them: No. > > No explanation, no "sorry", nothing but "no". These are not my kind of > people. A lot of old-line surplus businesses do not fare well with the expectations of the modern order-it-today-get-it-tomorrow-morning world. Some other businesses (e.g. Digikey, which was not always a big business, think back to their QST ads 30+ years ago where their only product was - gasp! - a digital keyer) have made the transition remarkably well and are in fact the benchmark of a modern catalog parts house. I think it is still valuable to have the "not really sorry" surplus places remain in business though. I've dealt with them long enough that even when I don't get a "sorry" I think I understand where they're coming from - and in many cases I also know who to ask for who knows the real story. The part-time help at the order desk is unfortunately not as good a resource as the guy who's been running the business for 30 or 40 or 50 years. Tim. Article: 98026 of rec.radio.amateur.homebrew From: Ben Jackson Subject: Re: SA602A oscillator load capacitance References: <3KWsg.3642$Th7.2568@trnddc05> Message-ID: Date: Wed, 12 Jul 2006 16:30:45 -0500 On 2006-07-11, W3JDR wrote: > "Ben Jackson" wrote in message > news:slrneb8a23.1gh6.ben@saturn.home.ben.com... >> I'm trying to figure out the load capacitance of the oscillator pins 6 >> and 7 on the SA602A. >> >> ...suggests...oscillator is about 8.5p. > > All things considered in your case, I'd use the series coupling approach. I like that idea, since the series capacitance reduces the effect of unknowns on the oscillator side. Using my estimate above and given my existing caps, I tried a 33p in series and got to 14.849995MHz, which is a vast improvement. Thanks! -- Ben Jackson AD7GD http://www.ben.com/ Article: 98027 of rec.radio.amateur.homebrew From: "Joel Kolstad" Subject: Re: Surplus Sales of Nebraska Date: Wed, 12 Jul 2006 14:36:47 -0700 Message-ID: <12baqrgiggoemad@corp.supernews.com> References: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> wrote in message news:1152717559.138675.155040@m79g2000cwm.googlegroups.com... > They told me the owner spends all day on the net trying to hunt down > surplus stuff he can buy. I've always been curious... places like All Electronics and MPJA and Hosfelt and ... that one near Dayton ... where did they find all their surplus *before* the Internet? There must have been publications or something that dealt with getting rid of surplus electronics? Article: 98028 of rec.radio.amateur.homebrew From: "K7ITM" Subject: Re: Toroid or molded inductor in low voltage tank? Date: 12 Jul 2006 16:39:54 -0700 Message-ID: <1152747594.902517.174460@35g2000cwc.googlegroups.com> References: Well, it's less of a problem than I'd have guessed. It turns out that I was already set up to measure inductance and Q of little toroid coils, since I'm winding some for some filters. These are on T25-6 cores. The one I measured for the results below has 22 turns of AWG28 wire on it, essentially evenly spaced around the core, with a gap of about 45 degrees between the wire ends. That is, the wire occupies about 7/8 of the core. I won't claim high absolute accuracy, but the Q measurement should be well within 10%, and the relative accuracy (from one condition to the next) should be much better than that. In particular, I can guarantee the direction that Q moves as I add shielding. The first measurement is with the toroid inductor standing vertically off a copper ground plane, with the core at the gap in the winding about a millimeter up from the plane. The second measurement adds a piece of copper foil tape stuck to the ground plane, and bent up at right angles to the ground plane so it's immediately adjacent to one side of the coil. The third measurement folds the copper foil over the top of the toroid and down the other side, so the coil is surrounded by copper foil. These are labelled 1, 2 and 3 below. Inductance Q 1 1.355uH 160 2 1.349uH 158 3 1.335uH 157 The actual drop in inductance is almost certainly a little more than indicated. That's because the copper foil adds capacitance, which would lower the resonant frequency and be seen by my measurement technique as increased apparent inductance. I could resolve that by making a similar measurement with lower resonating capacitance, but I'm not set up to do that right now. Of course, the lowered inductance is because the shield reduces the volume occupied by the magnetic field, so there is less energy stored in it for a given current. But these measurements tell me that even for the low-mu type 6 cores, there is quite a low external field. Cheers, Tom Roy Lewallen wrote: > John Hague wrote: > > On Tue, 11 Jul 2006 08:29:05 +0100, Roy Lewallen wrote: > > > >> Ben Jackson wrote: > >>> . . . > >>> Anyone have any tips for securing fine-wire toroids in > >>> Ugly/Manhattan construction? :) > >> > >> A dab of hot melt glue or RTV. Or a Nylon screw through the middle. Or > >> a couple of holes in the board and a cable tie. The only thing to > >> avoid is laying it down flat on a solid copper plane. > >> > >> Roy Lewallen, W7EL > > > > Roy > > > > Excuse my ignorance, but what is the problem with laying a toroid down > > on a solid copper plane? I thought the magnetic field was contained > > within the toroid and thus minimised external effects. I have completed > > a couple of projects recently with some of the inductors like that and > > didn't notice any real problem. Mind you, I guess they might have > > performed better if not mounted that way :o) > > Two potential problems. One is that the field isn't completely > contained. Leakage is greater with more sparsely wound toroids and ones > with lower permeability cores. The second is the "one turn effect" - > There's a net field equivalent to that of a single turn running > circumferentially around the core. A solid plane parallel to this would > act as a shorted turn. Both effects would act to lower the Q, and might > be the cause of some drift or microphonics if the inductor was in an > oscillator tank. > > But to be honest, I've never run any experiments to see just how much of > a problem it might cause -- it's quite possible you could get away with > it in some or even most applications. I'll put it on my list of things > to do when time permits -- unless somebody else is willing to take on > the job. > > Roy Lewallen, W7EL Article: 98029 of rec.radio.amateur.homebrew From: duane Subject: Re: Part Pinout References: Message-ID: Date: Thu, 13 Jul 2006 00:39:05 GMT Arlon Nelson wrote: > I'm in need of the pinout of a 3SK274 Dual Gate Mosfet. It has one short > lead and 3 long leads. > I have check my ARRL handbooks and cannot find out which one is > source,drain,g1 and g2 > > Thanks for any help > > Nels W0TUP Nells, The datasheet is available at http://www.datasheetarchive.com Duane de ke8bg Article: 98030 of rec.radio.amateur.homebrew From: "Joel Kolstad" Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes Date: Wed, 12 Jul 2006 20:34:58 -0700 Message-ID: <12bbfr36ah4def3@corp.supernews.com> References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> "erica" wrote in message news:1152701692.603004.306280@35g2000cwc.googlegroups.com... > Voltage 220V, 8A fused. ^^^^^^^^^^^^ This is something of a show-stopper for those of us in the US...