Article: 96780 of rec.radio.amateur.homebrew From: Paul Keinanen Subject: Re: A really basic question Message-ID: References: <4402cdfa$1_2@newspeer2.tds.net> Date: Wed, 01 Mar 2006 11:50:17 +0200 On Mon, 27 Feb 2006 12:07:53 -0500, "Lew" wrote: >To figure out your current draw: >Amps = Watts (in Kw) X 1000/(voltage X 1.732 X Pf) >Thats a very low power factor, what are you running? That would be the current per phase into a three phase load. Paul Article: 96781 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Date: Wed, 01 Mar 2006 10:52:41 +0000 On Wed, 01 Mar 2006 01:03:21 -0800, aadu.adok wrote: > hello, > > I'm building my first reciver. I can't choose what kind of mixers should I > use. I have read that diode ring mixers are far superior compared to dual > gate mosfet mixers. It depends on what you mean by superior. The mosfet mixer has gain and usually has a lower noise figure. The diode mixer will have superior strong signal handling (higher IP3), but will have about 7dB loss. The diode mixer needs more local oscillator power. They both make excellent mixers if they are applied properly. To get the most bang for your buck, it is hard to beat a ring of 1N914 or 1N4148 diodes at a few cent each. The ferrite 'cups' from scrap Toko IF transformers can be used as cores for the trifilar wound transformers. There are a few other options you should consider. High level IC mixers like the AD831 are worth considering. Switching mixers using MOSFETs are capable of very high performance. Search for info about the N6NWP front-end from QST Feb 93 or the H-mode mixer used in several recent homebrew designs. http://uk.groups.yahoo.com/group/picastar/ http://xoomer.virgilio.it/sergiocartoceti/article_7.htm http://www.warc.org.uk/cdg2000/introduction.htm If you build the receive mixer as a separate module, you can try them all and pick the one that works best for you. 73, Ed. EI9GQ. -- Linux 2.6.15 Remove 'X' to reply by e-mail. Yes, my username really is: nospam Article: 96782 of rec.radio.amateur.homebrew From: "2greedy" Subject: NEW WEBSITE Message-ID: <0ZfNf.18767$yK1.13640@news-server.bigpond.net.au> Date: Wed, 01 Mar 2006 11:55:40 GMT Have a look i think you will like it. http://www.vkcorner.com or http://www.vkcorner.com/forum/index.php Article: 96783 of rec.radio.amateur.homebrew From: "xpyttl" References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: Date: Wed, 1 Mar 2006 07:03:01 -0500 wrote in message news:1141203801.248815.322050@e56g2000cwe.googlegroups.com... > hello, > > I'm building my first reciver. I can't choose what kind of mixers > should I use. I have read that diode ring mixers are far superior > compared to dual gate mosfet mixers. "Superior" is something of a loaded word. Whether a particular parts is superior or not depends on your design intent. Probably the most popular mixer for simple HF receivers is the NE/SA 602/612. This is an active mixer. It has amazing amounts of gain, such that an RF stage is almost never needed. It is extremely simple to deploy, and it requires almost no power. Thus, in portable/battery powered circuits it is almost always the mixer of choice. It has an absolutely horrid TOIP. There are other, mostly older, even poorer, active mixers, but the 602 is a very versatile part, so it seems to show up everywhere. At the other extreme are diode ring mixers. These can have stellar TOIPs, but take a lot of oscillator power. Further, they need lots of RF as well, so some sort of RF stage is needed. All this adds up to a need for plenty of power. The best diode ring mixers will use matched, Schottky diodes, but good old 1N4148's do work, and quite well. Many designs use packaged diode ring mixers such as those from Minicircuits. The dual gate MOSFET falls kind of in the middle. It doesn't have the horrible TOIP problems of an active mixer, but it's not as power hungry as a diode ring. The MOSFET seems to have fallen out of favor lately, in spite of being a "balanced" sort of solution. I suspect most designers are either going for power consumption or performance, and really, quite good performance can be had with the active mixers with careful design. > Is this true for both - first (RF / VFO) and second (IF / BFO) stages? > Or is there any real difference at all? Careful design can manage what the second mixer sees more easily than than the first. This can make the dynamic range problems of an active mixer less of an issue. For that reason, balanced designs that tend toward management of power consumption will sometimes use a diode ring for the first IF and an active mixer for the second. But a superhet bent all out on power conservation will almost always use a pair of 602's. Designers who want to avoid ICs for whatever reason will use a pair of diode rings. I shouldn't sound so down on the 602. A WELL-DESIGNED 602 receiver can easily match the performance of the $1000 class rice box rigs. It cannot, however, come close to the performance of an equally well-designed diode ring rig. But the diode ring rig will probably consume three times the power, meaning three times the heat to deal with and the associated oscillator compensation issues. So you picks your poison. .. Article: 96784 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Date: Wed, 01 Mar 2006 12:58:06 GMT On 1 Mar 2006 01:03:21 -0800, aadu.adok@gmail.com wrote: >hello, > >I'm building my first reciver. I can't choose what kind of mixers >should I use. I have read that diode ring mixers are far superior >compared to dual gate mosfet mixers. DBMs are very good if properly applied but if improperly used they will disappoint the user. Their advatages is they are rugged, hard to overload and easy to build. Disadvantage, no gain rfamp may be needed, must have at least 5mw of LO power(some need more), are designed for around 50 ohm impedences at all ports. Dual gate MOSFET, popular many years ago, and generaly easy to apply with moderate overload resistance. The common reason for not being used as much is simply availbility. Common Jfets (u310, MPF102) inpairs can be used in a cascode compound connection with nearly equal performance as the MOSFETs without cost and ESD considerations. Advantage is good gain, low noise and low power. >Is this true for both - first (RF / VFO) and second (IF / BFO) stages? >Or is there any real difference at all? Depends on reciever design. I've seen Mosfets(or two Jfets) used for first mixer and DBM used for product detector. The idea there is a DBM and the end of an IF will see large signals and the overload resistance is valuable there. Like others have said superior varies depending on goals. One parmeter in this case of DBMs is the oscillator power needs and often the need for more gain stages. If you building a radio that runs on batteries then using more power may be bad. Alllison Article: 96785 of rec.radio.amateur.homebrew From: "xpyttl" References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: Date: Wed, 1 Mar 2006 09:04:13 -0500 wrote in message news:jr5b029tn5nkkdlpplatj3glp3sphbgbem@4ax.com... > If you building a radio that runs on > batteries then using more power may be bad. Also keep in mind that more power=more heat If you are building a simple analog VFO, temperature compensating the VFO can be the most tedious part of designing a receiver. Depending on how tight your box is, the difference in heat could be an issue. Keeping the oscillator stable while delivering more power also means more buffer stages between the VFO and the mixer. If you are designing with a DDS, of course, all this is pretty much moot. With a typical DDS chip and a packaged clock oscillator at some high frequency, the oscillator will draw so much current and generate so much heat that what the mixer requires is invisible. .. Article: 96786 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Date: Wed, 01 Mar 2006 16:22:19 GMT On Wed, 1 Mar 2006 09:04:13 -0500, "xpyttl" wrote: > wrote in message >news:jr5b029tn5nkkdlpplatj3glp3sphbgbem@4ax.com... > >> If you building a radio that runs on >> batteries then using more power may be bad. > >Also keep in mind that more power=more heat > >If you are building a simple analog VFO, temperature compensating the VFO >can be the most tedious part of designing a receiver. Depending on how >tight your box is, the difference in heat could be an issue. Keeping the >oscillator stable while delivering more power also means more buffer stages >between the VFO and the mixer. Actually even without the heat issue you still have to compensate it or ambient variation will drive you nuts. Granted a few transistors delivering 5-10mW of power is not a great heat generator when you add all the surrouding possible sources. >If you are designing with a DDS, of course, all this is pretty much moot. >With a typical DDS chip and a packaged clock oscillator at some high >frequency, the oscillator will draw so much current and generate so much >heat that what the mixer requires is invisible. Since buffereing the VFO is a good idea anyway the buffer and later statges can supply the 5 or more milliwatts needed for level 7 rings. Since those stages can be "remote" the small heat generated is not a big issue. However between a VFO, buffer and a buffer to deliver power you can be hitting 30-50mA and on batteries thats a bigger issue. If you using DDS, likely power is not an issue and the combined DDS and control plus display could be surprizingly high or at least has to be managed. However you approach the problem a little though to the overall effects are important. After all what usually seperates a great reciever from a passable one is attention to the little details. Allison Article: 96787 of rec.radio.amateur.homebrew From: Chris Jones Subject: Re: mixer: DBM or dual gate mosfet? Date: Wed, 01 Mar 2006 22:33:27 +0000 Message-ID: <120c89ob3mp2u39@corp.supernews.com> References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> aadu.adok@gmail.com wrote: > hello, > > I'm building my first reciver. I can't choose what kind of mixers > should I use. I have read that diode ring mixers are far superior > compared to dual gate mosfet mixers. > > Is this true for both - first (RF / VFO) and second (IF / BFO) stages? > Or is there any real difference at all? > > thanks I have recently bought the books from the RSGB which contain all of the Technical Topics columns from RadCom for the last couple of decades or so. It seems like they really like making mixers from FST3125 Bus Switch ICs, and up to perhaps 50MHz these are supposed to be much better than the average diode ring mixer. They call the configuration "H-mode" and the guy who I believe is supposed to have come up with the idea is called Colin Horrabin. Here is an article randomly selected from a google search: http:// xoomer.virgilio.it/sergiocartoceti/pdf%20files/IK4AUY_%20qex_07-2004.pdf I don't like the way they generate the LO signals with XOR gates but apart >from that it is interesting. Chris Article: 96788 of rec.radio.amateur.homebrew From: Ken Scharf Subject: Re: mixer: DBM or dual gate mosfet? References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Message-ID: Date: Wed, 01 Mar 2006 22:31:17 -0500 Allison-nospam@nouce.bellatlantic.net wrote: > On Wed, 1 Mar 2006 09:04:13 -0500, "xpyttl" > wrote: > > >> wrote in message >>news:jr5b029tn5nkkdlpplatj3glp3sphbgbem@4ax.com... >> >> >>>If you building a radio that runs on >>>batteries then using more power may be bad. >> >>Also keep in mind that more power=more heat >> >>If you are building a simple analog VFO, temperature compensating the VFO >>can be the most tedious part of designing a receiver. Depending on how >>tight your box is, the difference in heat could be an issue. Keeping the >>oscillator stable while delivering more power also means more buffer stages >>between the VFO and the mixer. > > > Actually even without the heat issue you still have to compensate it > or ambient variation will drive you nuts. Granted a few transistors > delivering 5-10mW of power is not a great heat generator when you add > all the surrouding possible sources. > > >>If you are designing with a DDS, of course, all this is pretty much moot. >>With a typical DDS chip and a packaged clock oscillator at some high >>frequency, the oscillator will draw so much current and generate so much >>heat that what the mixer requires is invisible. > > > Since buffereing the VFO is a good idea anyway the buffer and later > statges can supply the 5 or more milliwatts needed for level 7 rings. > Since those stages can be "remote" the small heat generated is not a > big issue. However between a VFO, buffer and a buffer to deliver > power you can be hitting 30-50mA and on batteries thats a bigger > issue. > > If you using DDS, likely power is not an issue and the combined DDS > and control plus display could be surprizingly high or at least has to > be managed. > > However you approach the problem a little though to the overall > effects are important. After all what usually seperates a great > reciever from a passable one is attention to the little details. > > > Allison Some of the modern DDS chips require little power. Analog Devices has some DDS chips that draw less than 50ma at 5v, I think there is one that takes but 15ma. True a vfo will draw even less, but we are not talking about gobs of power in any case. DDS vfo's have very low phase noise, and the ones that can be clocked at 100mhz or higher can deliver quite low spurs. The AD9954 series have a 14 bit DAC and can make a very good HFO for a single conversion receiver with no PLL loop filter needed to clean up the output. Article: 96789 of rec.radio.amateur.homebrew From: Ken Scharf Subject: Re: +7dB from BFO to diode ring mixer? References: <1141025584.002935.174890@t39g2000cwt.googlegroups.com> <1141034363.277170.286850@i40g2000cwc.googlegroups.com> <1141036376.797213.62500@e56g2000cwe.googlegroups.com> Message-ID: Date: Wed, 01 Mar 2006 22:35:34 -0500 Highland Ham wrote: >> There are various dBx measures of real signal characteristics. The >> most common ones that I know of are dBm (dB over 1mW), dBV (dB over >> 1V, presumably ignoring impedance and therefore really just a >> fancy-pants amplitude measure) and dBc (dB under carrier, very >> important stuff to measure phase noise in an oscillator or transmitter). > > ====================================== > RF power limitations (power into antenna) for the UK amateur radio > licences are expressed in dBW 26 dBW equals 400 Watts > 15 dBW equals 32 Watts etc . > > Frank GM0CSZ / KN6WH Why not just say Watts or milliwatts and be done with it? Why drag dB into it? BTW dB means deci-bell, why not use a WHOLE BELL. (and the brass figligee with bronze oak-leaf palm to anybody who can guess who this unit of measure was named after!) Article: 96790 of rec.radio.amateur.homebrew From: Roberto IZ5FCY Subject: Re: Looking for a GPS disciplined frequency synthesizer References: <1141278672.747780.34580@u72g2000cwu.googlegroups.com> Date: Thu, 2 Mar 2006 09:17:34 +0100 Message-ID: <18vxcu6xgme6j$.11um6y47pjmv0.dlg@40tude.net> Hi Phil, I suggest you to search in TAPR Web site for an synthetyzer kit, as you are looking for, for about 100US$.. -- 73's de IZ5FCY Roberto Article: 96791 of rec.radio.amateur.homebrew From: "Mike Andrews" Subject: Re: FA: Some nice HP gear from my home lab.... Date: Thu, 2 Mar 2006 10:50:02 +0000 (UTC) Message-ID: References: <1140240731.474865.35500@o13g2000cwo.googlegroups.com> <1141097112.718754.135310@u72g2000cwu.googlegroups.com> In rec.radio.amateur.homebrew jmiles@gmail.com wrote: > Winfield Hill wrote: >> I like the part where you get the "number of 1000-ns intervals >> since 1-Jan-1601 UTC" :-) > Heh... I've wondered where Microsoft came up with that; it might have > come from the Unix world. There's a lot of weirdness in the calendar > business, and it's usually less arbitrary, but more obscure, than it > seems at first. Do you take into account the days lost in the change from the Julian to the Gregorian calendars? -- Mike Andrews, W5EGO mikea@mikea.ath.cx Tired old sysadmin Article: 96792 of rec.radio.amateur.homebrew Date: Thu, 02 Mar 2006 16:20:07 +0200 From: Risto Tiilikainen Subject: Re: mixer: DBM or dual gate mosfet? References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Message-ID: <4406fe2e$0$25339$39db0f71@news.song.fi> aadu.adok@gmail.com wrote: >hello, > >I'm building my first reciver. I can't choose what kind of mixers >should I use. I have read that diode ring mixers are far superior >compared to dual gate mosfet mixers. > >Is this true for both - first (RF / VFO) and second (IF / BFO) stages? >Or is there any real difference at all? > >thanks > > > Hi If you think the situation in short waves today: Russian and their previous satellite country jammers are quiet Local broadcast is nearly completely in FM Propaganda is no more effective to transmit in short waves Commercial data is practically in Internet. and in satellites Marine communication is in satellites. All this means less cross modulation products in first mixer than some sixteen years ago Atmospheric noise in sw is much higher than the noise of modern front and mixer stage Advantage of diode mixer is marginal IGFET mixer is simple and advanced solution for DIY project. IGFET mixer doesn't need any front amplifier stage. A selective band filter in front of mixer is superior to broadband transformers I am using loosely coupled 3 stage band filter tuned by variable triplet air capacitor 3 coils for low end of sw and 3 coils for upper end of sw. Coils are DC selected by small reed relays KISS If you are constructing premixer then I recommend DBM to keep birdies in low levell For IF/BFO my recommendation is also DBM or "semi DBM" For both of those DBM solutions I recommend you to Google a nice advanced component MC1496. In some Motorola handbooks and ARRL handbooks are examples for MC1496 as DBM, product detector and balanced modulator. It is mostly used in single ended circuits in RF meaning and balanced for DC 73, Risto OH2BT Article: 96793 of rec.radio.amateur.homebrew Message-ID: <44072840.AAB9E0FE@earthlink.net> From: "Michael A. Terrell" Subject: Re: +7dB from BFO to diode ring mixer? References: <1141025584.002935.174890@t39g2000cwt.googlegroups.com> <1141034363.277170.286850@i40g2000cwc.googlegroups.com> <1141036376.797213.62500@e56g2000cwe.googlegroups.com> Date: Thu, 02 Mar 2006 17:16:15 GMT Ken Scharf wrote: > > BTW dB means deci-bell, why not use a WHOLE BELL. > (and the brass figligee with bronze oak-leaf palm to anybody > who can guess who this unit of measure was named after!) Well, it wasn't named after Watson, so that only leaves one man... -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida Article: 96794 of rec.radio.amateur.homebrew From: - exray - Subject: Re: +7dB from BFO to diode ring mixer? Date: Thu, 02 Mar 2006 13:38:50 -0400 Message-ID: <120ebd7ekhs6113@corp.supernews.com> References: <1141025584.002935.174890@t39g2000cwt.googlegroups.com> <1141034363.277170.286850@i40g2000cwc.googlegroups.com> <1141036376.797213.62500@e56g2000cwe.googlegroups.com> <44072840.AAB9E0FE@earthlink.net> Michael A. Terrell wrote: > Ken Scharf wrote: > >>BTW dB means deci-bell, why not use a WHOLE BELL. >>(and the brass figligee with bronze oak-leaf palm to anybody >>who can guess who this unit of measure was named after!) > > > > Well, it wasn't named after Watson, so that only leaves one man... > > Art Bell? -ex Article: 96795 of rec.radio.amateur.homebrew From: "Steve Nosko" Subject: Re: +7dB from BFO to diode ring mixer? Date: Thu, 2 Mar 2006 11:20:46 -0600 Message-ID: References: <1141025584.002935.174890@t39g2000cwt.googlegroups.com> <1141034363.277170.286850@i40g2000cwc.googlegroups.com> <1141036376.797213.62500@e56g2000cwe.googlegroups.com> Actually I believe the unit is a Bel. Yes 10 dB is one Bel. For some reason nobody uses the bel...or for that matter the milibel, microbel, kilobel or megabel... Decibels are just about right all the time. Perhaps it is because no one knows for whom it tolls... Perhaps "no one knows for whom the decibel decides." (:-) Also, we Engineers love to talk in dB... You can just add and subtract them... Then there is the practical aspects. If you have 0.1 watts going into an step attenuator set to 32dB, how much is coming out? However, starting with 20dBm into this attenuator yields an easy -12dBm. You get used to it, just like you got used to power in watts. 73, Steve, K9DCI PS: dBm is dB _relative to_ (not over) one mw. (-123 dBm is "under" a mw) "Ken Scharf" wrote in message news:eHtNf.42918$X7.21415@bignews7.bellsouth.net... > Highland Ham wrote: > >> There are various dBx measures of real signal characteristics. The > >> most common ones that I know of are dBm (dB over 1mW), dBV (dB over > >> 1V, presumably ignoring impedance and therefore really just a > >> fancy-pants amplitude measure) and dBc (dB under carrier, very > >> important stuff to measure phase noise in an oscillator or transmitter). > > > > ====================================== > > RF power limitations (power into antenna) for the UK amateur radio > > licences are expressed in dBW 26 dBW equals 400 Watts > > 15 dBW equals 32 Watts etc . > > > > Frank GM0CSZ / KN6WH > Why not just say Watts or milliwatts and be done with it? > Why drag dB into it? > > BTW dB means deci-bell, why not use a WHOLE BELL. > (and the brass figligee with bronze oak-leaf palm to anybody > who can guess who this unit of measure was named after!) Article: 96796 of rec.radio.amateur.homebrew From: fmmck@aol.com (Fred McKenzie) Subject: Re: Impedence mismatch into FET preamp Date: Thu, 02 Mar 2006 13:09:14 -0500 Message-ID: References: In article , "Samuel Hunt" wrote: > It's not due to desense. When I tune the cavities up properly, there's about > 10dB noise figure on the preamp (reciever is 0.8uV sensitive). Then when it > transmits, the noise figure doesn't change. Sam- What frequency is this repeater on? A sensitivity of 0.8 uV doesn't sound very good to me. On 146 MHz I'd expect that without any external preamp, although it might be good at 1200 MHz??? 73, Fred, K4DII Article: 96797 of rec.radio.amateur.homebrew From: dplatt@radagast.org (Dave Platt) Subject: Re: mixer: DBM or dual gate mosfet? Date: Thu, 02 Mar 2006 19:33:23 -0000 Message-ID: <120ei436906hh32@corp.supernews.com> References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> In article <4406fe2e$0$25339$39db0f71@news.song.fi>, Risto Tiilikainen wrote: >If you think the situation in short waves today: >Russian and their previous satellite country jammers are quiet >Local broadcast is nearly completely in FM >Propaganda is no more effective to transmit in short waves >Commercial data is practically in Internet. and in satellites >Marine communication is in satellites. > >All this means less cross modulation products in first mixer than some >sixteen years ago >Atmospheric noise in sw is much higher than the noise of modern front >and mixer stage >Advantage of diode mixer is marginal There's a good discussion about the advantages and disadvantages of various mixer types, for different applications, in "Experimental Methods in Radio Frequency Design", a book I strongly recommend. As others have pointed out, there's no one right solution. Even for use in what seems like a simple, constant application (e.g. a CW receiver for the 40-meter band), the choice of which is more appropriate can swing one way or the other based on how you intend to use the receiver. As one example given in EMiRFD, if you're looking for a simple receiver which is intended for QRP operation on backpacking trips, then the low power consumption, and the mixer gain of an active mixer such as a Gilbert cell (e.g. SA602 and similar) can make this the ideal. Out in the woods, the RF levels will be low, and the relatively low IP3 of these sorts of mixers isn't likely to be a problem. On the other hand, if you're planning to build a receiver which may have to operate in a strong-adjacent-signal environment (e.g. for Field Day or other contesting), then you may want to favor a diode-ring double-balanced mixer operating at a high LO-injection level, and the devil take the power consumption :-) The FET-switch mixers seem to be a really nice alternative, and although they've gotten relatively little visibility in amateur-radio applications they've become very popular in commercial use (e.g. cell-phone handsets). I haven't yet had a chance to play with these myself but they look like fun! -- 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: 96798 of rec.radio.amateur.homebrew From: Paul Keinanen Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Date: Thu, 02 Mar 2006 22:37:10 +0200 On Wed, 1 Mar 2006 07:03:01 -0500, "xpyttl" wrote: >Probably the most popular mixer for simple HF receivers is the NE/SA >602/612. This is an active mixer. It has amazing amounts of gain, such >that an RF stage is almost never needed. It is extremely simple to deploy, >and it requires almost no power. Thus, in portable/battery powered circuits >it is almost always the mixer of choice. It has an absolutely horrid TOIP. >There are other, mostly older, even poorer, active mixers, but the 602 is a >very versatile part, so it seems to show up everywhere. If you really intend to use mixers with such horrible IP3 figures, I would suggest using a very selective front end ahead of it. For a single band CW receiver some fixed tuned stages might suffice, but otherwise some tunable input filters should be used. In Europe, there are several high power broadcasters starting at 7100 kHz, which would easily overload the 40 m receiver. Assuming loaded Q of 100 and the front end tuned to 7000 kHz, the -3 dB bandwidth would be +/-35 kHz from the centre frequency with some usable attenuation at 7100 kHz. Using fixed tuned octave wide front end filters with the 602 is just asking for trouble. Paul OH3LWR Article: 96799 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: <6kqe02p4klge8l01nc794g30dj6uor8ejq@4ax.com> References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> Date: Thu, 02 Mar 2006 22:06:10 GMT On Thu, 02 Mar 2006 19:33:23 -0000, dplatt@radagast.org (Dave Platt) wrote: >In article <4406fe2e$0$25339$39db0f71@news.song.fi>, >Risto Tiilikainen wrote: > >>If you think the situation in short waves today: >>Russian and their previous satellite country jammers are quiet >>Local broadcast is nearly completely in FM >>Propaganda is no more effective to transmit in short waves >>Commercial data is practically in Internet. and in satellites >>Marine communication is in satellites. >> >>All this means less cross modulation products in first mixer than some >>sixteen years ago >>Atmospheric noise in sw is much higher than the noise of modern front >>and mixer stage >>Advantage of diode mixer is marginal > >There's a good discussion about the advantages and disadvantages of >various mixer types, for different applications, in "Experimental >Methods in Radio Frequency Design", a book I strongly recommend. > >As others have pointed out, there's no one right solution. Even for >use in what seems like a simple, constant application (e.g. a CW >receiver for the 40-meter band), the choice of which is more >appropriate can swing one way or the other based on how you intend to >use the receiver. > >As one example given in EMiRFD, if you're looking for a simple >receiver which is intended for QRP operation on backpacking trips, >then the low power consumption, and the mixer gain of an active mixer >such as a Gilbert cell (e.g. SA602 and similar) can make this the >ideal. Out in the woods, the RF levels will be low, and the >relatively low IP3 of these sorts of mixers isn't likely to be a >problem. The lowly SA/NE602 isn't so bad considering the power it uses and the 15-17db of gain it offers. Like any power power mixer care in use is important. >On the other hand, if you're planning to build a receiver which may >have to operate in a strong-adjacent-signal environment (e.g. for >Field Day or other contesting), then you may want to favor a >diode-ring double-balanced mixer operating at a high LO-injection >level, and the devil take the power consumption :-) Even then with care in generating the power it's not that bad. >The FET-switch mixers seem to be a really nice alternative, and >although they've gotten relatively little visibility in amateur-radio >applications they've become very popular in commercial use (e.g. >cell-phone handsets). I haven't yet had a chance to play with these >myself but they look like fun! I have, really nice devices but a challenge to build circuits with good symetry at higher frequencies like 6M and up. Some of the layouts can be a bear to drive properly and have the same port impedence matching considerations as DBMs. They also still have losses in th e6-8db range so gain distribution requires care. However singally balanced FET mixers have been around for a while and can offer good IP3 with simplier design. Over the years several designs using both active mixers (single and dual gate [mos and junction] FETS) as well as MOSfets, and transistors in passive modes. The nadbooks and QST and Ham Radio featured these designs for bands such as 40M where broadcasters are a problem. Allison Article: 96800 of rec.radio.amateur.homebrew From: "Reg Edwards" Subject: New program CONNECT Date: Fri, 3 Mar 2006 02:02:27 +0000 (UTC) Message-ID: There have been recent discussions about the interchangeability of coaxial plugs and sockets, their dimensions and their impedances. But, as usual, the magnitude of the electrical effects is never mentioned. Without numbers nobody knows what they are talking about. A coaxial connector is a very short length of transmission line but at UHF and microwave frequencies it is an appreciable fraction of a wavelength. When 1/4-wavelength long it has the property of transforming a mismatched termination to another value. When 1/2-wavelength long the input impedance repeats the value of the termination. The SWR on an adjacent line is a function of the input impedance. What is the effect of using a 75-ohm coaxial connector in a 50-ohm system? What is the effect of using a length of transmission line of 50-ohms nominal impedance when it is actually 53 ohms? With mixed values of line Zo at what high frequency does the SWR and reflection loss become excessive? Program CONNECT.exe calculates the effect of inserting a length of line in a system of different Zo. Differences can be large or small. Line length can be physically very short. For a given frequency, mismatched Zo's and a velocity factor, input impedance, SWR, reflection coefficient and reflection loss are calculated. (Reflection loss is sometime known as mismatch loss). The program is worded in terms of a connector mismatch but has other applications. Input data can be varied in small increments from the keyboard while observing the effects on calculated values. Download CONNECT from website below. It has entertainment, educationaal and practical value. Amuse yourselves! ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 96801 of rec.radio.amateur.homebrew From: "xpyttl" References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: Date: Thu, 2 Mar 2006 21:11:16 -0500 "Paul Keinanen" wrote in message news:e2le025mgm1kn1h3e0ucs38bapmvrsrsaa@4ax.com... > In Europe, there are several high power broadcasters starting at 7100 > kHz, which would easily overload the 40 m receiver. Assuming loaded Q OH2BT's comments about how much better things have gotten in Europe really made me say hmmmm.... I only recently heard actual measurements, rather than whining, and things are pretty horrible today - they must have been intolerable decades ago. Tight front ends and careful control of levels obviously are important with any mixer, but especially something with the gain of a 602. Nevertheless, I doubt there are many cases where a 602 would be even useable in Europe, let alone "good". .. Article: 96802 of rec.radio.amateur.homebrew From: Paul Keinanen Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: <03nf02daf2hltbjiq2n1ivncjik6ah3vvr@4ax.com> References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> Date: Fri, 03 Mar 2006 09:29:30 +0200 On Thu, 2 Mar 2006 21:11:16 -0500, "xpyttl" wrote: >"Paul Keinanen" wrote in message >news:e2le025mgm1kn1h3e0ucs38bapmvrsrsaa@4ax.com... > >> In Europe, there are several high power broadcasters starting at 7100 >> kHz, which would easily overload the 40 m receiver. Assuming loaded Q > >OH2BT's comments about how much better things have gotten in Europe really >made me say hmmmm.... I only recently heard actual measurements, rather >than whining, and things are pretty horrible today - they must have been >intolerable decades ago. We had problems keeping Radio Moscow out of _audio_ equipment :-). Guitar amplifiers were quite problematic with long cables and a top capacitance (the guitar and the player) at the end, bringing quite large RF voltages into the audio stages, causing rectification in unfiltered input stages. Paul OH3LWR Article: 96803 of rec.radio.amateur.homebrew From: Paul Keinanen Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <6kqe02p4klge8l01nc794g30dj6uor8ejq@4ax.com> Date: Fri, 03 Mar 2006 09:29:31 +0200 On Thu, 02 Mar 2006 22:06:10 GMT, Allison-nospam@nouce.bellatlantic.net wrote: >The lowly SA/NE602 isn't so bad considering the power it uses and the >15-17db of gain it offers. Like any power power mixer care in use is >important. Certainly usable for receiving strong international broadcasters, in which case the input signals can be sufficiently attenuated, however, trying to receive any weak signals with such an attenuator at the front end, is not very productive :-) Paul OH3LWR Article: 96804 of rec.radio.amateur.homebrew From: "owen.home" References: <1141025584.002935.174890@t39g2000cwt.googlegroups.com> <1141034363.277170.286850@i40g2000cwc.googlegroups.com> <1141036376.797213.62500@e56g2000cwe.googlegroups.com> Subject: Re: +7dB from BFO to diode ring mixer? Message-ID: Date: Fri, 03 Mar 2006 09:40:51 GMT "Steve Nosko" wrote in message news:du79he$bni$2@engnntp2.cig.mot.com... > Actually I believe the unit is a Bel. Yes 10 dB is one Bel. For some > reason nobody uses the bel...or for that matter the milibel, microbel, This may interest some. I believe, although can't find the actual reference now, that the decibel was used rather than the bel from the start because the numbers were very close to those of the m.s.c. used before it. The following are from "Signal Training" Vol 2, Part 3 (Line telephony and Telegraphy) 1936, HMSO, an Army training manual:- " The decibel.- The standard unit for measurement of telephone transmission in this country [UK] is now the decibel, which is one-tenth of a bel, and has superseded the mile of standard cable." and "1 decibel = 1.084 m.s.c. = 1.151 decineper" "1 m.s.c. = 0.9221 decibel = 1.0616 necineper" and just to explain the decineper "In the majority of European countries the unit of measurement for telephone transmission is the decineper, which is one-tenth of one Neper. The unit is named after Napier, the originator of Naperian or natural logarithms, i.e. logarithms to the base e. The neper is a measurement of the total attenuation and can be defined as the natural logarithm of the ratio of the currents at two different points in a network or apparatus, or as half the natural logarithm of the ratio of powers at two different points in a network or apparatus." The book doesn't show an upper case B for Bel in db so that must have come later but it does use the plural as in "30dbs" so should we be using dbuVs etc? I've used an artificial cable box for 75 ohm video but have never seen a reference m.s.c., originally an actual lump of cable but later a series of switched networks. John MW1FGQ Article: 96805 of rec.radio.amateur.homebrew From: "Samuel Hunt" Subject: Re: Impedence mismatch into FET preamp Date: Fri, 3 Mar 2006 12:00:53 +0000 (UTC) Message-ID: References: <1141148974.021206.227170@p10g2000cwp.googlegroups.com> I think that basically is the problem. Because the impedance is not set up properly on the cavities (the pass plunger is a little off the correct impedance), then the preamp is operating with a non-optimal impedance. Desensing the preamp reduces the gain so reduces the amount of noise the preamp is generating. Sounds like a little lesson well learnt to me. Now on to returning the cavities up properly.....; Thanks all, Sam "K7ITM" wrote in message news:1141148974.021206.227170@p10g2000cwp.googlegroups.com... > It's important to realize that the optimum match for noise is in > general NOT the same as matching the impedance seen at the FET input. > The optimum impedance to match to is the FET's input-referred noise > voltage at the frequency of interest, divided by the corresponding > noise current. RF transistor data sheets will often list the impedance > for optimum noise figure. The difference between impedance matching > for maximum power transfer and lowest noise figure can be significant. > This is true with both bipolars and FETs. > > Not sure what's going on with the change in noise as the repeater keys > up. Any chance some of the xmt RF is being rectified and changing the > bias on the preamp? > > Cheers, > Tom > Article: 96806 of rec.radio.amateur.homebrew From: Spike Subject: Re: now here sumfing funee Date: Fri, 03 Mar 2006 13:25:53 +0000 Message-ID: References: <1zONf.52778$Fy4.35344@newsfe4-win.ntli.net> <1141381005.776058.89420@i39g2000cwa.googlegroups.com> Mike G4KFK wrote: >Each electron pushes and shoves it's neighbours backwards and forwards >along the wire - so although the net motion of any given electron in >nil Or very nearly so. As it's Friday afternoon, I'm sure the Complete Buffoon (CB) who seems to speak Copious Bowlocks (CB) when it comes to matters scientific, will be along soon with his Chattering Balderdash (CB), in which he might explain a previous posting maintaining that electrons 'whizz about'. On the other hand, he just might carry on ranting about the Copper's Boot (CB) and trying to make a Casus Bellum (CB) out of it. After all, Cui Bono (CB), as one might ask? Cheery Bye (CB). from Aero Spike Article: 96807 of rec.radio.amateur.homebrew From: "2K1LO" Subject: Re: now here sumfing funee Date: Fri, 3 Mar 2006 13:48:25 +0000 (UTC) Message-ID: References: <1zONf.52778$Fy4.35344@newsfe4-win.ntli.net> <1141381005.776058.89420@i39g2000cwa.googlegroups.com> "Spike" wrote in message news:msfg021e67grt30qub1hhisramgc3it7e4@4ax.com... > > Mike G4KFK wrote: > >>Each electron pushes and shoves it's neighbours backwards and forwards >>along the wire - so although the net motion of any given electron in >>nil > > Or very nearly so. Quite, - there is some wobble and skin effect. With DC there is movement in one direction however the speed is in the orders of inches per hour so that's pretty much nil too IMHO ;-) -- 73de2K1LO -- -------------------------------------------- eQSO Gateway at http://www.g1lvn.org.uk -------------------------------------------- From "know code" Fri Mar 3 23:54:19 EST 2006 Article: 96808 of rec.radio.amateur.homebrew Date: Fri, 03 Mar 2006 17:01:37 +0100 From: know code Reply-To: "know code" User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 Newsgroups: uk.radio.amateur,rec.radio.amateur.policy,rec.radio.amateur.homebrew Subject: Re: Radio Hammery - The Weekly FAQ References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> In-Reply-To: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 7 Message-ID: <44086860$0$17159$dbd41001@news.wanadoo.nl> Organization: Wanadoo NNTP-Posting-Date: 03 Mar 2006 16:01:36 GMT NNTP-Posting-Host: s5591cd23.adsl.wanadoo.nl X-Trace: 1141401696 dr3.euro.net 17159 85.145.205.35:2196 X-Complaints-To: abuse@wanadoo.nl Path: news1.isis.unc.edu!canoe.uoregon.edu!hammer.uoregon.edu!news.glorb.com!multikabel.net!feed20.multikabel.net!news2.euro.net!postnews2.euro.net!news.wanadoo.nl!not-for-mail Xref: news1.isis.unc.edu uk.radio.amateur:268338 rec.radio.amateur.policy:257226 rec.radio.amateur.homebrew:96808 Plod's Conscience wrote: > What is Ham Radio? Beanies been let out for the weekend again, I see :) Article: 96809 of rec.radio.amateur.homebrew From: "Brian Reay" References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> Subject: Re: Radio Hammery - The Weekly FAQ Message-ID: Date: Fri, 03 Mar 2006 16:04:57 GMT "know code" wrote in message news:44086860$0$17159$dbd41001@news.wanadoo.nl... > Plod's Conscience wrote: >> What is Ham Radio? > > > Beanies been let out for the weekend again, I see :) At least we only have to suffer him at weekends. Maybe you should follow his example. Brian Article: 96810 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Ten-Tec 1054 Shortwave Kit Message-ID: References: <1141011981.987128.18370@e56g2000cwe.googlegroups.com> <1141049127.758407.212160@j33g2000cwa.googlegroups.com> <1141074644.712905.40950@z34g2000cwc.googlegroups.com> <1141399814.152776.61220@z34g2000cwc.googlegroups.com> Date: Fri, 03 Mar 2006 16:09:40 GMT On 3 Mar 2006 07:30:14 -0800, "dave_meade@yahoo.com" wrote: >I discovered that the solder connections on a capacitor were bad. >Apparently, the solder iron overheated the contacts on the board >causing plastic on the board to melt onto the contact. I made a >temporary fix by soldering the capacitor directly to the resistors it >is connecting. I'm picking up radio stations now, but there is a loud >squeal. Maybe the timer is oscillating? Is there anything that can >clean melted plastic off a contact? Timer??? I assume the detector is oscillating, adjustment of the regeneration control should clear that up. If not maybe it's either bad or miswired? Heat will clean the melted plastic, use care as excess heat could cause other damage. What plastic by the way? The board it self would be hard to melt with a soldering iron. Allison From "know code" Fri Mar 3 23:54:20 EST 2006 Article: 96811 of rec.radio.amateur.homebrew Date: Fri, 03 Mar 2006 17:20:05 +0100 From: know code Reply-To: "know code" User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 Newsgroups: uk.radio.amateur,rec.radio.amateur.policy,rec.radio.amateur.homebrew Subject: Re: Radio Hammery - The Weekly FAQ References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 12 Message-ID: <44086cb4$0$17159$dbd41001@news.wanadoo.nl> Organization: Wanadoo NNTP-Posting-Date: 03 Mar 2006 16:20:04 GMT NNTP-Posting-Host: s5591cd23.adsl.wanadoo.nl X-Trace: 1141402804 dr3.euro.net 17159 85.145.205.35:2196 X-Complaints-To: abuse@wanadoo.nl Path: news1.isis.unc.edu!elk.ncren.net!logbridge.uoregon.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!newsgate.cistron.nl!news2.euro.net!postnews2.euro.net!news.wanadoo.nl!not-for-mail Xref: news1.isis.unc.edu uk.radio.amateur:268341 rec.radio.amateur.policy:257228 rec.radio.amateur.homebrew:96811 Brian Reay wrote: > "know code" wrote in message > news:44086860$0$17159$dbd41001@news.wanadoo.nl... >> Plod's Conscience wrote: >>> What is Ham Radio? >> >> Beanies been let out for the weekend again, I see :) > > At least we only have to suffer him at weekends. Maybe you should follow his > example. TWO words Brian.... Glass houses! From "know code" Fri Mar 3 23:54:20 EST 2006 Article: 96812 of rec.radio.amateur.homebrew Date: Fri, 03 Mar 2006 17:51:45 +0100 From: know code Reply-To: "know code" User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 Newsgroups: uk.radio.amateur,rec.radio.amateur.policy,rec.radio.amateur.homebrew Subject: Re: Radio Hammery - The Weekly FAQ References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> <44086cb4$0$17159$dbd41001@news.wanadoo.nl> <1141404225.547875.178820@i40g2000cwc.googlegroups.com> In-Reply-To: <1141404225.547875.178820@i40g2000cwc.googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 17 Message-ID: <4408741f$0$17159$dbd41001@news.wanadoo.nl> Organization: Wanadoo NNTP-Posting-Date: 03 Mar 2006 16:51:43 GMT NNTP-Posting-Host: s5591cd23.adsl.wanadoo.nl X-Trace: 1141404703 dr3.euro.net 17159 85.145.205.35:2196 X-Complaints-To: abuse@wanadoo.nl Path: news1.isis.unc.edu!canoe.uoregon.edu!hammer.uoregon.edu!news.wind.surfnet.nl!surfnet.nl!surfnet.nl!feeder.enertel.nl!nntpfeed-01.ops.asmr-01.energis-idc.net!news2.euro.net!postnews2.euro.net!news.wanadoo.nl!not-for-mail Xref: news1.isis.unc.edu uk.radio.amateur:268342 rec.radio.amateur.policy:257229 rec.radio.amateur.homebrew:96812 an_old_friend wrote: > know code wrote: >> Brian Reay wrote: >>> "know code" wrote in message >>> news:44086860$0$17159$dbd41001@news.wanadoo.nl... >>>> Plod's Conscience wrote: >>>>> What is Ham Radio? >>>> Beanies been let out for the weekend again, I see :) >>> At least we only have to suffer him at weekends. Maybe you should follow his >>> example. >> TWO words Brian.... Glass houses! > > i guess you have a weekend pass from the nut house > > hmm the man that shot gets those I wonder... Care to try that again? And try to make some sense this time! Article: 96813 of rec.radio.amateur.homebrew From: "Old Nicks Deputy \(first class\)" References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> <44086cb4$0$17159$dbd41001@news.wanadoo.nl> Subject: Re: Radio Hammery - The Weekly FAQ Message-ID: <7w_Nf.54649$Fy4.33852@newsfe4-win.ntli.net> Date: Fri, 03 Mar 2006 16:53:23 GMT "know code" wrote in message news:44086cb4$0$17159$dbd41001@news.wanadoo.nl... > Brian Reay wrote: >> "know code" wrote in message >> news:44086860$0$17159$dbd41001@news.wanadoo.nl... > > TWO words Brian.... Glass houses! Is that where you spent your National Service? tox From "know code" Fri Mar 3 23:54:20 EST 2006 Article: 96814 of rec.radio.amateur.homebrew Date: Fri, 03 Mar 2006 17:57:35 +0100 From: know code Reply-To: "know code" User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 Newsgroups: uk.radio.amateur,rec.radio.amateur.policy,rec.radio.amateur.homebrew Subject: Re: Radio Hammery - The Weekly FAQ References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> <44086cb4$0$17159$dbd41001@news.wanadoo.nl> <7w_Nf.54649$Fy4.33852@newsfe4-win.ntli.net> In-Reply-To: <7w_Nf.54649$Fy4.33852@newsfe4-win.ntli.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 13 Message-ID: <4408757e$0$17159$dbd41001@news.wanadoo.nl> Organization: Wanadoo NNTP-Posting-Date: 03 Mar 2006 16:57:34 GMT NNTP-Posting-Host: s5591cd23.adsl.wanadoo.nl X-Trace: 1141405054 dr3.euro.net 17159 85.145.205.35:2196 X-Complaints-To: abuse@wanadoo.nl Path: news1.isis.unc.edu!canoe.uoregon.edu!hammer.uoregon.edu!news.glorb.com!multikabel.net!feed20.multikabel.net!news2.euro.net!postnews2.euro.net!news.wanadoo.nl!not-for-mail Xref: news1.isis.unc.edu uk.radio.amateur:268345 rec.radio.amateur.policy:257231 rec.radio.amateur.homebrew:96814 Old Nicks Deputy (first class) wrote: > "know code" wrote in message > news:44086cb4$0$17159$dbd41001@news.wanadoo.nl... >> Brian Reay wrote: >>> "know code" wrote in message >>> news:44086860$0$17159$dbd41001@news.wanadoo.nl... > > >> TWO words Brian.... Glass houses! > > Is that where you spent your National Service? National Service? I'm not *that* old :) Article: 96815 of rec.radio.amateur.homebrew From: "DieSea" References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> <44086cb4$0$17159$dbd41001@news.wanadoo.nl> <7w_Nf.54649$Fy4.33852@newsfe4-win.ntli.net> Subject: Re: Radio Hammery - The Weekly FAQ Date: Fri, 3 Mar 2006 16:58:53 -0000 Message-ID: <440875c7$0$5009$db0fefd9@news.zen.co.uk> "Old Nicks Deputy (first class)" wrote in message news:7w_Nf.54649$Fy4.33852@newsfe4-win.ntli.net... > > "know code" wrote in message > news:44086cb4$0$17159$dbd41001@news.wanadoo.nl... >> Brian Reay wrote: >>> "know code" wrote in message >>> news:44086860$0$17159$dbd41001@news.wanadoo.nl... > > >> >> TWO words Brian.... Glass houses! > > Is that where you spent your National Service? > > tox > Shepton or Colchester Tox You'll be near Colchester this weekend methinks Have they allowed you to escape from Yorkshire Pity if they have You and Nick could improve the place Yorkshire that is DieSea Article: 96816 of rec.radio.amateur.homebrew From: "Old Nicks Deputy \(first class\)" References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> <44086cb4$0$17159$dbd41001@news.wanadoo.nl> <7w_Nf.54649$Fy4.33852@newsfe4-win.ntli.net> <440875c7$0$5009$db0fefd9@news.zen.co.uk> Subject: Re: Radio Hammery - The Weekly FAQ Message-ID: Date: Fri, 03 Mar 2006 17:29:15 GMT "DieSea" wrote in message news:440875c7$0$5009$db0fefd9@news.zen.co.uk... > >> > > Shepton or Colchester Tox > > You'll be near Colchester this weekend methinks Indeed, DieSea. Although the weather looks iffy...Nick up to his usual tricks with another rally :-( > Have they allowed you to escape from Yorkshire Yes, until Tuesday, when I have a meeting in Morley, Bradford. > Pity if they have > > You and Nick could improve the place > > Yorkshire that is Nick seems to think a Hydrogen bomb would improve the place significantly...and who am I to argue! Regards tox Article: 96817 of rec.radio.amateur.homebrew From: "The Magnum" Subject: Re: Radio Hammery - The Weekly FAQ Date: Fri, 3 Mar 2006 17:42:43 -0000 Message-ID: References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> <1141402311.747132.47960@t39g2000cwt.googlegroups.com> "Mike G4KFK" wrote in message news:1141402311.747132.47960@t39g2000cwt.googlegroups.com... > > know code wrote: > > Beanies been let out for the weekend again, I see :) > > I thought he was supposed to be watching his blood pressure? He is... that's why he probably does a cut and paste posting the same stuff every weekend rather than post anything interesting. One is also beginning to think either that or he has a newsgroup bot automatically posting his mail for him and set for the weekend. Graham -- -.-. -... / .-. .- -.. .. --- Radio is only a Hobby. Don't let it rule your life... 73/51 - Graham, 26-Golf Charlie-19 Article: 96818 of rec.radio.amateur.homebrew From: "Brian Reay" References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> <1141402311.747132.47960@t39g2000cwt.googlegroups.com> Subject: Re: Radio Hammery - The Weekly FAQ Message-ID: <5A%Nf.70061$m13.23849@newsfe5-gui.ntli.net> Date: Fri, 03 Mar 2006 18:05:53 GMT "Mike G4KFK" wrote in message news:1141402311.747132.47960@t39g2000cwt.googlegroups.com... > > I thought he was supposed to be watching his blood pressure? Some doctors recommend a moderate amount of alcohol to reduce high blood pressure. Make it red wine and you can reduce your cholesterol at the same time ;-) Of course, too much alcohol isn't a good thing, it can lead to long term brain damage and all sorts of mental problems. -- 73 Brian www.g8osn.org.uk Article: 96819 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Ten-Tec 1054 Shortwave Kit Message-ID: References: <1141011981.987128.18370@e56g2000cwe.googlegroups.com> <1141049127.758407.212160@j33g2000cwa.googlegroups.com> <1141074644.712905.40950@z34g2000cwc.googlegroups.com> <1141399814.152776.61220@z34g2000cwc.googlegroups.com> <1141404387.479156.131570@p10g2000cwp.googlegroups.com> Date: Fri, 03 Mar 2006 18:59:59 GMT On 3 Mar 2006 08:46:27 -0800, "dave_meade@yahoo.com" wrote: >I think the board has some kind of plastic or polymer coating because >the heat from the solder iron causes the clear coating to melt. I'll >hook the circuit up to an o-scope to see what part is oscillating. I >suspect something is miswired, I'll let you guys know later in the week >how it went. Thanks for everyone's help! That's the soldermask. Soldermask is the name of the coating applied to the etch (other than the pad areas). You should not have to "melt" the mask unless you peeled the etch and now need a new contact area. Likely the regeneration control has a bad connection at one end. Another source of problems in electrolytic capacators installed backward. Weak batteries can be a source of problems. Allison Article: 96820 of rec.radio.amateur.homebrew From: class-a-licensee-pkearn-zBBpk@didnt-run-away-from-a-morse-test.es.eircom.com.net (zBBPK) Subject: Re: Radio Hammery - The Weekly FAQ Date: Fri, 03 Mar 2006 20:06:52 GMT Message-ID: <4408a1ca.5876710@news.iol.ie> References: <1141400672.399979.311270@i39g2000cwa.googlegroups.com> <44086860$0$17159$dbd41001@news.wanadoo.nl> "Brian Reay" wrote: > At least we only have to suffer him at weekends. Maybe you should follow his > example. whereas with you its all week long... tee hee Article: 96821 of rec.radio.amateur.homebrew From: Ken Scharf Subject: Re: mixer: DBM or dual gate mosfet? References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> Message-ID: <2F7Of.879$s8.113@bignews7.bellsouth.net> Date: Fri, 03 Mar 2006 22:20:28 -0500 > The FET-switch mixers seem to be a really nice alternative, and > although they've gotten relatively little visibility in amateur-radio > applications they've become very popular in commercial use (e.g. > cell-phone handsets). I haven't yet had a chance to play with these > myself but they look like fun! > There was an article in the ARRL HB (1995 and probably others) about using an SD5000 quad mosfet as a mixer. I bought a few of these transistors a few years ago (now where did I put them, got lost in the last move!). They are supposed to make a very good mixer. The only disadvantage was the circuit required injection at twice the lo frequency as it used a jk flip flop to develop the required 180 degree injection. I suppose a balum could do the same thing. In any case the AD9954 DDS I am thinking of using can clock to 400mhz and develop output to 160mhz, so getting up to 80mhz (for use with a 9mhz if) would still be no problem. Article: 96822 of rec.radio.amateur.homebrew From: "Tom" Subject: FA: Unbuilt Heath Scope Kit - Ends Saturday Message-ID: Date: Sat, 04 Mar 2006 04:12:20 GMT Unbuilt Kit - 70's Vintage Heathkit Oscilloscope. Complete - Original Box - Parts Inventoried - No Reserve. Click on: http://tinyurl.com/mvygq Ends Saturday Feb-22-06 16:07:24 PST (Sunday Feb-23-06 00:07:24 UTC) Many thanks es 73, Tom NØJMY Article: 96823 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Permeability of steel filled epoxy? Date: Fri, 03 Mar 2006 22:37:01 -0800 Message-ID: <120idcg9lbo5pcc@corp.supernews.com> References: <1141425652.682734.94300@e56g2000cwe.googlegroups.com> <0sSdnd1G-vnmrZTZnZ2dnUVZ_vudnZ2d@web-ster.com> Air (or epoxy -- doesn't matter as long as the relative permeability is 1) gaps between the particles will have a much greater impact on the characteristics than the steel itself. Compared to the steel itself, the material will have much lower permeability, much higher saturation flux density, and much lower hysteresis. I'll bet the repeatability will be pretty awful. Roy Lewallen, W7EL Tim Wescott wrote: > cs_posting@hotmail.com wrote: > >> Anyone have a guess as to the permeability of steel filled epoxy? >> >> Was sort of wondering what would happen if one tried to make RF >> inductor or transformer (torroid, etc) cores out of the stuff... >> >> with care, it can even reproduce threads, so tuneable slugs might be >> possible. >> >> It's available as putty in tube form in many hardware stores, and as a >> castable liquid from industrial supply catalogs - though obviously if >> ordering something from a non-local supplier, it might as well be a >> proper core from Amidon. >> >> (and yes, I may go ahead and try it... soon as I get my workbench set >> back up to the point where I could build something to measure the >> results) >> > I would expect that you would have problems with loss due to hysteresis > in the steel. A good big pile of rust may be better. > > I wonder: if you had your Jr. Experimenter's Chemistry set and a pile of > iron filings, what would make the best core material? > Article: 96824 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> Date: Sat, 04 Mar 2006 10:05:16 +0000 On Fri, 03 Mar 2006 22:20:28 -0500, Ken Scharf wrote: > There was an article in the ARRL HB (1995 and probably others) about using > an SD5000 quad mosfet as a mixer. Also see N6NWP's article from QST June 1993. And the H-mode mixer by G3SBI in RadCom and various other RSGB publications. > I bought a few of these transistors a few years ago... I see the SD5000 is still listed on Calogic's website http://www.calogic.net/html/dmos.html Is the SD5000 still widely available? The search engines turn up a lot of data but very few suppliers. Perhaps a ring of discrete MOSFETs or a fast switch IC like the FST3125 might be a better choice. 73, Ed. EI9GQ. -- Linux 2.6.15 Remove 'X' to reply by e-mail. Yes, my username really is: nospam Article: 96825 of rec.radio.amateur.homebrew Date: Sat, 04 Mar 2006 12:18:55 +0200 From: Risto Tiilikainen Subject: Re: mixer: DBM or dual gate mosfet? References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> Message-ID: <440968a3$0$7478$39db0f71@news.song.fi> Ken Scharf wrote: >>The FET-switch mixers seem to be a really nice alternative, and >>although they've gotten relatively little visibility in amateur-radio >>applications they've become very popular in commercial use (e.g. >>cell-phone handsets). I haven't yet had a chance to play with these >>myself but they look like fun! >> >> >> >There was an article in the ARRL HB (1995 and probably others) >about using an SD5000 quad mosfet as a mixer. I bought a few >of these transistors a few years ago (now where did I put them, >got lost in the last move!). They are supposed to make >a very good mixer. The only disadvantage was the circuit >required injection at twice the lo frequency as it used a jk flip >flop to develop the required 180 degree injection. I suppose >a balum could do the same thing. In any case the AD9954 DDS I am >thinking of using can clock to 400mhz and develop output to >160mhz, so getting up to 80mhz (for use with a 9mhz if) would still >be no problem. > > Hi ! At the same time Signetics included to the same fet family a double fet SD6000 It was planned for front end applications Single fets were done under type numbers SD305 and SD306 All three were N-channel enhancement types. Positive bias only. I wonder whether Signetics still exists. Signetics was bought by Philips company. I use those fets successfully in one of my conventional type homebrew tranceivers. The first if is having a 10.7 MHz xtal filter. That is mixed down to 455 kHz either with 10.245 MHz or 11.155 MHz xtal Sideband selection is done with the selection of mixing direction. 455 kHz is using Collins mechanical filter having very good shape factor and special skirt for lower sideband use. 73, Risto OH2BT Article: 96826 of rec.radio.amateur.homebrew From: "Harold E. Johnson" References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: Date: Sat, 04 Mar 2006 12:48:53 GMT > I see the SD5000 is still listed on Calogic's website > http://www.calogic.net/html/dmos.html Is the SD5000 > still widely available? The search engines turn up a > lot of data but very few suppliers. Perhaps a ring of > discrete MOSFETs or a fast switch IC like the FST3125 > might be a better choice. > > 73, Ed. EI9GQ. GM Ed. Certainly a better choice when it comes to conversion loss. I've built a half dozen SD5000 mixers and although at least one of them managed a measured +50 dBm Ip3, (G3SBI measured it not me!) I never managed to get the conversion loss below 9 dB and more often 10. Conversely, the 3125/ family readily does 4.8 dB conversion loss thanks to the very respectable Rds on. REALLY simplifies things in the front end department, to at least 30 MHz, with attention paid to the front end filters, you can get away without an RF amplifier. Regards W4ZCB Article: 96827 of rec.radio.amateur.homebrew From: "DOUGLAS SNOWDEN" Subject: Question about 4-400 tube socket/mounting Message-ID: Date: Sun, 05 Mar 2006 01:33:34 GMT I have seen 3-500Z tubes mounted in the johnson ceramic sockets. The Heath SB-220 uses them. Will the 4-400 tube handle the airflow the same way? Usually you see the air system sockets used so that the air will flow up through the bottom. Will the filament connections remain solid in a 275 ceramic socket with a muffin fan blowing across the tube? ? I have seen the sockets raised a bit so that the filaments get cooling. Just wondering if the 4-400 would work that way as well? Any experience with this? Doug N4IJ Article: 96828 of rec.radio.amateur.homebrew From: "Jeff James" Subject: Buy and Sell Vintage Gear! Message-ID: Date: Sun, 5 Mar 2006 00:06:36 -0500 http://www.dealamerica.com/deal/cgi-bin/ads/bcads.cgi -The Boatanchor Classifieds- FREE ads and a site dedicated to Vintage Amateur Radio... You never know what you'll find.. Article: 96829 of rec.radio.amateur.homebrew From: Your@email.adr Subject: Please read - nothing nasty Message-ID: Date: Sun, 05 Mar 2006 10:52:40 GMT I want start a trend, this is make ppl to think carefully about where they live and how we are screwing it up, and the cures. goto my site and look i am a disabled ex-truck driver, and i have to find a new career, so this it, i want to plant a few trees, My site url :-) http://www.global-airconditioning.com/index.html its on a candian server my name and address is fully available I want help, and thats very hard for me to say. i don't lie it costs too much, truth hurts but it costs nothing, phishers beware, balderdash is binned Article: 96830 of rec.radio.amateur.homebrew From: "Floatything" Subject: Radio tracking a tortoise - help! Message-ID: Date: Sun, 05 Mar 2006 11:16:32 GMT Every year, Shelly the tortoise gets lost or manages to escape the garden. It can take days to find her. I would like to build a locating device so that I can track her down. The basic requirements are: a) that the 'transmitter (transponder?) on the tortoise is as small as possible. b) that it can be made by an electronics numpty. I have basic soldering skills, and can eventually work out a circuit diagram. Can anyone point me in the right direction? TIA Floatything (an escapee from uk.rec.sailing) Article: 96831 of rec.radio.amateur.homebrew From: "Ian" References: Subject: Re: Radio tracking a tortoise - help! Message-ID: Date: Sun, 05 Mar 2006 13:09:11 GMT "Floatything" wrote in message news:kMzOf.27366$Ru5.1396@newsfe6-gui.ntli.net... > Every year, Shelly the tortoise gets lost or manages to escape the garden. > It can take days to find her. I would like to build a locating device so > that I can track her down. > The basic requirements are: > Use a blob of epoxy resin with a long string stuck in it and tie it to a post! Either that or glue a mobile to it and call each night - you should hear the ringtone. You can already get small tracking devices if you look on a search engine such as GOOGLE. I didn't think people still had tortoise! They go for between £400 and £500 in the UK depending on the seller and people in some countries eat the poor things. They turn them upside down and cut the insides out. Quite revolting. Article: 96832 of rec.radio.amateur.homebrew From: Juul Geleick Subject: 6J6 convertor Date: Sun, 05 Mar 2006 17:14:44 +0100 Message-ID: Hi folks, when I was young, in de 60-ties, I build a so called 6J6 balance 145mHz convertor. But I lost the diagram. And I will build it again. Can anyone help? thanks, Juul Geleick - PE0GJG (The Netherlands) Article: 96833 of rec.radio.amateur.homebrew From: "Bill Turner" Subject: Re: 6J6 convertor References: Message-ID: <440bb971$1_3@newsfeed.slurp.net> Date: 5 Mar 2006 23:24:17 -0500 ORIGINAL MESSAGE: Juul Geleick wrote: > Hi folks, > when I was young, in de 60-ties, I build a so called 6J6 balance > 145mHz convertor. > But I lost the diagram. And I will build it again. > Can anyone help? > > thanks, > > Juul Geleick - PE0GJG (The Netherlands) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A fun project, but I'd recommend a different tube. The 6J6 was notorious for intermittents. It was a bad design from the start. In my other life as a TV repair guy, I changed hundreds of them. 73, Bill W6WRT Article: 96834 of rec.radio.amateur.homebrew From: Subject: kenwood tk-690 anyone have a schematic they can post for the kpg-43 ? same txd rxd data line Date: 06 Mar 2006 05:17:10 GMT Message-ID: <440bc5d5$0$4006$c3e8da3@news.astraweb.com> Article: 96835 of rec.radio.amateur.homebrew From: "Bob" Subject: Coherent CW Date: Mon, 6 Mar 2006 09:14:59 -0600 Message-ID: <120okfk2nguet3e@corp.supernews.com> Hi gang, Is there anyone still playing around with this mode? tnx Bob WB0POQ Article: 96836 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: SN 602, SA602 etc. for an R4C Message-ID: References: Date: Mon, 06 Mar 2006 17:38:44 GMT On Mon, 6 Mar 2006 10:44:38 -0500, "Andy Bullington" wrote: >I'm really interested in building the product detector and second and third >mixers for my R4C as described in the recent QEX article. My question is >(and please pardon my ignorance) in 2 places an SN 602 IC is called for but >I can find no trace of such a component anywhere. Is the SA 602 or NE 602 >the same? I'm a ham but a musician by trade and learning this stuff as I go. >Thanks in advance. > Andy W1AWB > Looked at the article and it's a misprint, NE/SA602 are the same thing. The true believers will argue they are not identical but, for R4C service they are interchangeable. Allison Article: 96837 of rec.radio.amateur.homebrew From: "Caveat Lector" References: <120okfk2nguet3e@corp.supernews.com> <1141694240.515014.144720@z34g2000cwc.googlegroups.com> Subject: Re: Coherent CW Message-ID: Date: Mon, 6 Mar 2006 18:17:52 -0800 For Coherent CW - go to http://www.google.com/ Type in Coherent CW -- gets lots of articles Quick bottom line Coherent CW is morse code with precise timing and frequency accuracy, so you can use 20Hz filters and integrators to get remarkable results from very weak signals. -- CL -- I doubt, therefore I might be ! wrote in message news:1141694240.515014.144720@z34g2000cwc.googlegroups.com... > I've never before heard it described as "Coherent CW", but CW is hard > to avoid on any of the HF bands. > > Harry C. >