Article: 98031 of rec.radio.amateur.homebrew Date: Thu, 13 Jul 2006 10:54:21 +0100 From: Highland Ham Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> Message-ID: >> Voltage 220V, 8A fused. > > ^^^^^^^^^^^^ This is something of a show-stopper for those of us in the > US... ======================= With 117 V being the normal nominal domestic voltage , I believe many premises in the US have nominal 234 V outlets as well , hence 220V wouldn't be a problem.........let alone be a 'show stopper' Frank GM0CSZ / KN6WH Article: 98032 of rec.radio.amateur.homebrew From: Rex Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes Date: Thu, 13 Jul 2006 03:02:58 -0700 Message-ID: <996cb21j48aqghhigjficd6upqig3q36mq@4ax.com> References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> On Thu, 13 Jul 2006 10:54:21 +0100, Highland Ham wrote: >>> Voltage 220V, 8A fused. >> >> ^^^^^^^^^^^^ This is something of a show-stopper for those of us in the >> US... >======================= >With 117 V being the normal nominal domestic voltage , I believe many >premises in the US have nominal 234 V outlets as well , hence 220V >wouldn't be a problem.........let alone be a 'show stopper' > >Frank GM0CSZ / KN6WH The normal US home has two sockets that provide 220 V -- one for a kitchen range and one for a clothes dryer. Both are big (like 30+ amp) connectors. So, yes, it is a problem. Article: 98033 of rec.radio.amateur.homebrew From: "W3JDR" References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes Message-ID: Date: Thu, 13 Jul 2006 10:06:11 GMT Not true at all! 220V outlets are very rare in residences - no need for them as 220V is only used for very high power equipment. The exceptions would be central air conditioners, electric stoves, electric water heaters, but these are typically hard-wired in a junction box. Run-of-the-mill appliances using up to about 20 amps are usually run on 110VAC Joe W3JDR "Highland Ham" wrote in message news:NYGdnS1Qx4fVhSvZnZ2dnUVZ8qCdnZ2d@pipex.net... >>> Voltage 220V, 8A fused. >> >> ^^^^^^^^^^^^ This is something of a show-stopper for those of us in >> the US... > ======================= > With 117 V being the normal nominal domestic voltage , I believe many > premises in the US have nominal 234 V outlets as well , hence 220V > wouldn't be a problem.........let alone be a 'show stopper' > > Frank GM0CSZ / KN6WH Article: 98034 of rec.radio.amateur.homebrew From: "W3JDR" References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <1152712716.004638.184560@m73g2000cwd.googlegroups.com> Subject: Re: Class C amps saturating? Message-ID: Date: Thu, 13 Jul 2006 10:16:54 GMT >What says the group? Do we saturate in Class C or not? ----------------------- In order to get any semblence of efficiency, the drive waveform should drive the stage from near-cut-off to near-saturation, somewhat like a switch. However, depending on how hard the sinusoidal input signal drives the "Clacc C" stage, the conduction-angle and thus the duty-cycle of the output (before filtering) will increase or decrease, resulting in variable output power in the load. Joe W3JDR "Tim Shoppa" wrote in message news:1152712716.004638.184560@m73g2000cwd.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: 98035 of rec.radio.amateur.homebrew Date: Thu, 13 Jul 2006 11:25:30 +0100 From: Highland Ham Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> Message-ID: <6eqdnZAnw_wIgivZRVnyig@pipex.net> > 220V outlets are very rare in residences - no need for them as 220V is only > used for very high power equipment. The exceptions would be central air > conditioners, electric stoves, electric water heaters, but these are > typically hard-wired in a junction box. Run-of-the-mill appliances using up > to about 20 amps are usually run on 110VAC ==================================== Does the above mean that radio hams with a 1500 W RF (legal limit) power Amplifier will need an additional dedicated 220-234 V outlet in their shack ? Or would such an outlet be available anyway in relatively new houses ,built after say 199x ? Just 2 questions . Frank GM0CSZ / KN6WH Article: 98037 of rec.radio.amateur.homebrew From: Rex Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes Date: Thu, 13 Jul 2006 04:46:08 -0700 Message-ID: References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> <6eqdnZAnw_wIgivZRVnyig@pipex.net> On Thu, 13 Jul 2006 11:25:30 +0100, Highland Ham wrote: >> 220V outlets are very rare in residences - no need for them as 220V is only >> used for very high power equipment. The exceptions would be central air >> conditioners, electric stoves, electric water heaters, but these are >> typically hard-wired in a junction box. Run-of-the-mill appliances using up >> to about 20 amps are usually run on 110VAC >==================================== >Does the above mean that radio hams with a 1500 W RF (legal limit) power >Amplifier will need an additional dedicated 220-234 V outlet in their >shack ? Or would such an outlet be available anyway in relatively new >houses ,built after say 199x ? >Just 2 questions . > >Frank GM0CSZ / KN6WH > Yes No Article: 98038 of rec.radio.amateur.homebrew From: "Joel Kolstad" Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes Date: Thu, 13 Jul 2006 08:41:37 -0700 Message-ID: <12bcqdhhh8nij5d@corp.supernews.com> References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> "Highland Ham" wrote in message news:NYGdnS1Qx4fVhSvZnZ2dnUVZ8qCdnZ2d@pipex.net... >>> Voltage 220V, 8A fused. >> ^^^^^^^^^^^^ This is something of a show-stopper for those of us in the >> US... > ======================= > With 117 V being the normal nominal domestic voltage , I believe many > premises in the US have nominal 234 V outlets as well , hence 220V wouldn't > be a problem.........let alone be a 'show stopper' OK, I should have written it's a show-stopper for *many* people in the US. :-) Article: 98039 of rec.radio.amateur.homebrew From: "Steve N." Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes Date: Thu, 13 Jul 2006 17:04:26 -0500 Message-ID: References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> "Joel Kolstad" wrote in message news:12bbfr36ah4def3@corp.supernews.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... > ALL us homes have 220 brought to the fuse / breaker box. It is a 220 volt, center tapped transformer on the pole and all three lines are brought to the breaker box. . Each half of this winding supplies the 120, 110, 117, whatever you choose to call it. Half of the circuits in your home come from one of the winding ends (phase) and the center tap is connected to the common; the other half come from the other "phase".. Therefore you have two phases of 120 and they are 180 degrees apart. Some call it single phase, I think it should be called two phase...cuz it is. (:-) If you really need to get 220 quickly and easily [ and do not draw more than than the 15 or 20 amps of your brealers] you can find two outlets on the two phases and get one half of the 220 from each. I did this for a visiting relative from Germany so he could run his electric shaver. It is still the talk of the relatives... Since I built my house and did the wiring with Dad's help, I kept a drawing of all the circuits, I knew that I already had two phases in the guest room. A couple of cheap extension cords was all it took, with one blade of a "three prong adaprer" inserted into each hot side of each extension. Guest 220 in 5 minutes! I'd feel ok drawing 8A this way, but you shouldn't try this at home...I'm a professional. (:-) Linears should have either 1- both 110 and 220 internal wiring options, or 2- just 220 But 120 is is a real stretch. 73, Steve, K9DCI Article: 98040 of rec.radio.amateur.homebrew From: "jack" References: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> Subject: Re: Surplus Sales of Nebraska Date: Fri, 14 Jul 2006 07:35:44 -0400 Message-ID: wrote in message news: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. I purchase polystyrene caps from them. Speaking of Fair Radio Sales -- I bought a BC-348 from them in 1996 -- Article: 98041 of rec.radio.amateur.homebrew From: David Subject: Off-Topic question rgarding marketing Message-ID: Date: Fri, 14 Jul 2006 00:02:16 GMT Hi, I was wondering if anyone here might have some good ideas regarding promotion of our web site. The company was formed mainly from a technical base and one of the weaknesses is learning how to let others know we are here. I believe we have an excellent range of wireless solutions that have been designed to provide robust and reliable performance. The initial customers be have serviced to date are happy with our products but we need a larger customer base to survive. The site was constructed by myself but as I am not particularly experienced with web design it has plenty of room for improvement. Currently the only advertising I use is per click on yahoo and google. Thanks in advance for any constructive comments that may help point me in the right direction. Even some comments on whether the site is appearing correctly in your browser or comments on ease of use, clarity etc. (Still completing photos and datasheets so some pages are acting more as place holders while I complete the information. -- Kind Regards David ----------------------------------------------------------- ORBIT COMMUNICATIONS Pty Ltd - Wireless Solutions that Work (Telemetry, Control, Monitoring, Security, HVAC ...) A.C.N. 107 441 869 Website : http://www.orbitcoms.com PO Box 4474 Lakehaven NSW 2263, AUSTRALIA Phone: 61-2-4393-3627 Fax : 61-2-4393-3685 Mobile: 61-413-715-986 Article: 98042 of rec.radio.amateur.homebrew From: "W3JDR" References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <12b996ni52vq167@corp.supernews.com> Subject: Re: Class C amps saturating? Message-ID: Date: Fri, 14 Jul 2006 00:08:40 GMT The 'power dissipation' in a Cass C stage is primarily a function of what percentage of the cycle the stage is neither in saturation nor cutoff. A perfectly rectangular output switching waveform of any duty cycle , if it could be achieved, would result in nearly 100% efficiency. Joe W3JDR "Ben Jackson" wrote in message news:slrneb9a4j.1t6t.ben@saturn.home.ben.com... > 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: 98043 of rec.radio.amateur.homebrew From: Mike Burch Subject: Re: Surplus Sales of Nebraska References: <1152717559.138675.155040@m79g2000cwm.googlegroups.com> <6v9ab21u7i8ss7k07fs47k70emppedh703@4ax.com> Message-ID: Date: Fri, 14 Jul 2006 01:23:39 GMT I agree, I would only shop there if I had surplus dollars and surplus time. I don't have either. Their stuff is extremely expensive and there is always an alternative if you look hard enough. Mike K8MB Apache Junction, AZ > > 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: 98044 of rec.radio.amateur.homebrew From: "Reg Edwards" References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <12b996ni52vq167@corp.supernews.com> Subject: Re: Class C amps saturating? Date: Fri, 14 Jul 2006 05:23:20 +0100 Message-ID: > The 'power dissipation' in a Cass C stage is primarily a function of what > percentage of the cycle the stage is neither in saturation nor cutoff. A > perfectly rectangular output switching waveform of any duty cycle , if it > could be achieved, would result in nearly 100% efficiency. > > Joe > W3JDR =================================== Unfortunately, it makes a terrible mess of any modulation. To avoid distortion and non-linearity, saturation can be permitted only on the extreme peaks of the modulated driving waveform. Class-C is ruled out. Class-B or Class-AB prevails. ---- Reg. Article: 98045 of rec.radio.amateur.homebrew From: dplatt@radagast.org (Dave Platt) Subject: Re: Class C amps saturating? Date: Fri, 14 Jul 2006 06:22:07 -0000 Message-ID: <12bee0fpcoe7p48@corp.supernews.com> References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> In article , Reg Edwards wrote: >=================================== > >Unfortunately, it makes a terrible mess of any modulation. > >To avoid distortion and non-linearity, saturation can be permitted >only on the extreme peaks of the modulated driving waveform. Class-C >is ruled out. Class-B or Class-AB prevails. My recollection is that Classes B and AB are used for AM and SSB, while Class C works fine for CW and for FM. -- 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: 98046 of rec.radio.amateur.homebrew From: "W3JDR" References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <1152712716.004638.184560@m73g2000cwd.googlegroups.com> Subject: Re: Class C amps saturating? Message-ID: Date: Fri, 14 Jul 2006 09:32:18 GMT Yes, exactly. We just assume sinusoidal drive because that's the most common case Joe W3JDR "John - KD5YI" wrote in message news:DzDtg.17708$Wh7.10655@trnddc07... > W3JDR wrote: >> >> In order to get any semblence of efficiency, the drive waveform should >> drive the stage from near-cut-off to near-saturation, somewhat like a >> switch. However, depending on how hard the sinusoidal input signal drives >> the "Clacc C" stage, the conduction-angle and thus the duty-cycle of the >> output (before filtering) will increase or decrease, resulting in >> variable output power in the load. >> >> Joe >> W3JDR > > > Who said the drive had to be sinusoidal? If the final can run almost > square wave, why can't the driver? Article: 98047 of rec.radio.amateur.homebrew From: "W3JDR" References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <12b996ni52vq167@corp.supernews.com> Subject: Re: Class C amps saturating? Message-ID: Date: Fri, 14 Jul 2006 09:36:18 GMT >Unfortunately, it makes a terrible mess of any modulation ------------------------- Reg, Well not ANY modulation, just signals with amplitude modulation components. But this is a well-known property of Class C amplifiers, so what's the point?. If we want to talk about Class B or Class A, we should start a new thread. Joe W3JDR "Reg Edwards" wrote in message news:FZmdnbpjh56IgCrZnZ2dnUVZ8qqdnZ2d@bt.com... > >> The 'power dissipation' in a Cass C stage is primarily a function of > what >> percentage of the cycle the stage is neither in saturation nor > cutoff. A >> perfectly rectangular output switching waveform of any duty cycle , > if it >> could be achieved, would result in nearly 100% efficiency. >> >> Joe >> W3JDR > =================================== > > Unfortunately, it makes a terrible mess of any modulation. > > To avoid distortion and non-linearity, saturation can be permitted > only on the extreme peaks of the modulated driving waveform. Class-C > is ruled out. Class-B or Class-AB prevails. > ---- > Reg. > > Article: 98048 of rec.radio.amateur.homebrew Message-ID: Subject: toroid cores? From: nospam@geniegate.com (Jamie) Date: Fri, 14 Jul 2006 09:42:06 GMT Hi Newsgroup, Been trying to make a regen radio out of garbage. So far, I seem to have all the parts and it almost seems to work, however, I'm a bit confused about the inductance of toroid cores. I've tried to use one of those things from the back of a monitor (presumably to prevent RF interference) as one of the coils and another adjustable coil >from another device, to no avail. It has no markings and it appears to be a ferrite device in the shape of a ring. Anyone know an easy way to figure out how many turns to get (presumably 300mh?) >from one of these? Can I measure it with a ruler and some how get a formula for the number of turns / mH ? Are these really bad deviced to use? (the thought occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) Here's the circuit I'm basing it on: http://www.tricountyi.net/~randerse/regen.htm If I inject a signal directly into the coil (in place of his amplified RF "front stage") I can pick it up, but no oscillation and lousy tuning. (comes in on pretty much 1/2 the dial) I'm assuming this has something to do with the tank circuit. (I have two air capacitors totalling around 360pf one from a console stereo, the other from some place I can't remember where..) He's got 25T and 23T specified for a T-50-2 coil. Closest research on these that I can find is that this should produce about 300mh (but I could be wrong! anyone know for sure what the mH is on that?) This seems to make sense from everything I've read so far, but.. I have no way to measure it. If I end up using an air core, would I keep the ratio of turns for the tickler and injection coil? (where he has 3 and 5 turns spec'd) ? It's my assumption that in these two smaller coils, it's a step up transformer so it'd be a matter of ratios, am I correct in this assumption? Every bit of the circuit should come from garbage (the MPF102's I had to buy, but thats it) Even the coil wire is from the transformer of a broken microwave, the LM386 chip used for audio (and some resistors) will come from an old modem and the pot is a 500k pot, (from a console) wired in parallel with a ~>10k resistor to give a range between 0 - 10k ohms. The main point is to build it from garbage, I already have a radio and don't really "need" one, but.. as I once built a tube version of this (far simpler) doing one in solid state appeals to me. Jamie -- http://www.geniegate.com Custom web programming guhzo_42@lnubb.pbz (rot13) User Management Solutions Article: 98049 of rec.radio.amateur.homebrew Date: Fri, 14 Jul 2006 11:15:48 +0000 From: Scott Subject: Re: toroid cores? References: Message-ID: Check this page from Amidon Associates. They are a great supplier of toroids to the ham community! http://www.amidoncorp.com/aai_ironpowdercores.htm Looks to me like 25 turns on a T-50-2 core will give about 3 MICRO Henries according to Amidon's formula... Scott N0EDV Jamie wrote: > Hi Newsgroup, > > Been trying to make a regen radio out of garbage. So far, I seem to have > all the parts and it almost seems to work, however, I'm a bit confused > about the inductance of toroid cores. > > I've tried to use one of those things from the back of a monitor (presumably > to prevent RF interference) as one of the coils and another adjustable coil > from another device, to no avail. It has no markings and it appears to be > a ferrite device in the shape of a ring. > > Anyone know an easy way to figure out how many turns to get (presumably 300mh?) > from one of these? Can I measure it with a ruler and some how get a formula > for the number of turns / mH ? Are these really bad deviced to use? (the thought > occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) > > Here's the circuit I'm basing it on: > > http://www.tricountyi.net/~randerse/regen.htm > > If I inject a signal directly into the coil (in place of his amplified RF "front > stage") I can pick it up, but no oscillation and lousy tuning. (comes in on pretty > much 1/2 the dial) I'm assuming this has something to do with the tank circuit. (I have > two air capacitors totalling around 360pf one from a console stereo, the other from > some place I can't remember where..) > > He's got 25T and 23T specified for a T-50-2 coil. Closest research on these that > I can find is that this should produce about 300mh (but I could be wrong! anyone know > for sure what the mH is on that?) This seems to make sense from everything I've read > so far, but.. I have no way to measure it. > > If I end up using an air core, would I keep the ratio of turns for the tickler and > injection coil? (where he has 3 and 5 turns spec'd) ? It's my assumption that > in these two smaller coils, it's a step up transformer so it'd be a matter of ratios, > am I correct in this assumption? > > Every bit of the circuit should come from garbage (the MPF102's I had to buy, but thats > it) Even the coil wire is from the transformer of a broken microwave, the LM386 chip used > for audio (and some resistors) will come from an old modem and the pot is a 500k pot, > (from a console) wired in parallel with a ~>10k resistor to give a range between 0 - 10k ohms. > > The main point is to build it from garbage, I already have a radio and don't > really "need" one, but.. as I once built a tube version of this (far simpler) > doing one in solid state appeals to me. > > Jamie Article: 98050 of rec.radio.amateur.homebrew Date: Fri, 14 Jul 2006 12:24:57 +0100 From: Highland Ham Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> Message-ID: > I knew that I already had two phases in the guest room. > A couple of cheap extension cords was all it took, with one blade of a > "three prong adaprer" inserted into each hot side of each extension. Guest > 220 in 5 minutes! > > I'd feel ok drawing 8A this way, but you shouldn't try this at home...I'm a > professional. (:-) > > Linears should have either > 1- both 110 and 220 internal wiring options, or > 2- just 220 > > But 120 is is a real stretch. ====================== Steve , Tnx for providing the 'full' picture. Assuming a 67 percent efficiency (am I too pessimistic?) a legal RF power amp would need 1.5*1500 = 2250 W (say overall maximum of 2400W) which at 220 V means 12 Amperes. So, a shack without 220 -234 V power supply would need a dedicated supply from the switchboard . Here in the UK we do have 115V industrial power tools,which need to be used with a 230/115V (usually portable) safety transformer with the secondary having an earthed centre tap ,such that in the event of a 'fault' personnel is exposed to a (peak) voltage not exceeding 1.4*58 = 81V which is considered sufficiently low to prevent electrocution. The nominal domestic supply voltage within EU countries has now been 'normalised' to 230V ,meaning that (within a voltage band) the same equipment can be used in all the countries. Before , the UK had 240V and continental countries 220V . This often meant that for example an (clothing) iron for 220 V had a very limited life when used in Britain . The voltage at my place (rural area) is nowadays usually 236-237 V ,whereas earlier it was up to 250 V or sometimes even higher. Frank GM0CSZ / KN6WH Article: 98051 of rec.radio.amateur.homebrew From: "Reg Edwards" References: <1152683914.666244.144780@b28g2000cwb.googlegroups.com> <12b996ni52vq167@corp.supernews.com> Subject: Re: Class C amps saturating? Date: Fri, 14 Jul 2006 12:32:35 +0100 Message-ID: "W3JDR" wrote > The 'power dissipation' in a Cass C stage is primarily a function of what > percentage of the cycle the stage is neither in saturation nor cutoff. A > perfectly rectangular output switching waveform of any duty cycle , if it > could be achieved, would result in nearly 100% efficiency. > > Joe > W3JDR ======================================= All power amplifiers have a tuned circuit in the plate. It is essential to reduce output power contained in the harmonics. In any case, power in the harmonics is wasted power. With a tuned circuit in the plate it is impossible to achieve a rectangular voltage output waveform. It is always a sinewaveform. A rectangular plate current in conjunction with a tuned load always causes harmonic power to be wasted at the plate. So one might just as well use a sinusoidal driving waveform, Class-C or not. It's easier. It also avoids generating and wasting harmonic power in the driver. ---- Reg Article: 98052 of rec.radio.amateur.homebrew From: skavanagh72nospam@yahoo.ca Subject: Re: toroid cores? Date: 14 Jul 2006 04:42:47 -0700 Message-ID: <1152877367.450775.256530@h48g2000cwc.googlegroups.com> References: Jamie wrote: > I've tried to use one of those things from the back of a monitor (presumably > to prevent RF interference) as one of the coils and another adjustable coil > from another device, to no avail. It has no markings and it appears to be > a ferrite device in the shape of a ring. > > Anyone know an easy way to figure out how many turns to get (presumably 300mh?) > from one of these? Can I measure it with a ruler and some how get a formula > for the number of turns / mH ? Are these really bad deviced to use? (the thought > occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) Yes, I would expect they would be really bad ! If you knew the permeability of the material used then measuring with a ruler and applying some math (I don't know the formulas) would in theory get you an iductance calculation. But the materials used for these EMI chokes generally has too high a permeability to make inductors with convenient numbers of turns for the HF bands, and generally is quite lossy so the resulting inductors will have low Q. It is extremely unlikely to work. Since you don't want to buy any parts, I would recommend once you figure out the required inductance from the Amidon formulas, just wind air core coils (well, some sort of low loss former like a piece of plastic tubing is probably needed) with the same inductance. Inductance formulas for air core coils are available everywhere in handbooks and on the web. You might have to play with the number of turns in the feedback link though, as the coupling between it and the main coil will not be as tight in an air core coil as in the toroid. I would start with the same ratio of turns or maybe add a bit to the feedback coil. 73, Steve VE3SMA Article: 98053 of rec.radio.amateur.homebrew Date: Fri, 14 Jul 2006 06:51:35 -0700 From: Tim Wescott Subject: Re: toroid cores? References: <1152877367.450775.256530@h48g2000cwc.googlegroups.com> Message-ID: skavanagh72nospam@yahoo.ca wrote: > Jamie wrote: > > >>I've tried to use one of those things from the back of a monitor (presumably >>to prevent RF interference) as one of the coils and another adjustable coil >>from another device, to no avail. It has no markings and it appears to be >>a ferrite device in the shape of a ring. >> >>Anyone know an easy way to figure out how many turns to get (presumably 300mh?) >>from one of these? Can I measure it with a ruler and some how get a formula >>for the number of turns / mH ? Are these really bad deviced to use? (the thought >>occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) > > > Yes, I would expect they would be really bad ! If you knew the > permeability of the material used then measuring with a ruler and > applying some math (I don't know the formulas) would in theory get you > an iductance calculation. But the materials used for these EMI chokes > generally has too high a permeability to make inductors with convenient > numbers of turns for the HF bands, and generally is quite lossy so the > resulting inductors will have low Q. It is extremely unlikely to work. > > Since you don't want to buy any parts, I would recommend once you > figure out the required inductance from the Amidon formulas, just wind > air core coils (well, some sort of low loss former like a piece of > plastic tubing is probably needed) with the same inductance. > Inductance formulas for air core coils are available everywhere in > handbooks and on the web. You might have to play with the number of > turns in the feedback link though, as the coupling between it and the > main coil will not be as tight in an air core coil as in the toroid. I > would start with the same ratio of turns or maybe add a bit to the > feedback coil. > > 73, > Steve VE3SMA > If it's a broadcast band radio a toilet paper tube will work well. If ham band then something smaller like a sample-size shampoo bottle. Does it count as garbage if you buy the stuff so you'll have the 'garbage' when you're done? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Posting from Google? See http://cfaj.freeshell.org/google/ "Applied Control Theory for Embedded Systems" came out in April. See details at http://www.wescottdesign.com/actfes/actfes.html Article: 98054 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: toroid cores? Message-ID: <309fb21i39n8qlhrrnobbpj5jc1u26pq5s@4ax.com> References: Date: Fri, 14 Jul 2006 14:05:49 GMT On Fri, 14 Jul 2006 09:42:06 GMT, nospam@geniegate.com (Jamie) wrote: >Hi Newsgroup, > >Been trying to make a regen radio out of garbage. So far, I seem to have >all the parts and it almost seems to work, however, I'm a bit confused >about the inductance of toroid cores. > >I've tried to use one of those things from the back of a monitor (presumably >to prevent RF interference) as one of the coils and another adjustable coil >from another device, to no avail. It has no markings and it appears to be >a ferrite device in the shape of a ring. > >Anyone know an easy way to figure out how many turns to get (presumably 300mh?) >from one of these? Can I measure it with a ruler and some how get a formula >for the number of turns / mH ? Are these really bad deviced to use? (the thought >occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) > >Here's the circuit I'm basing it on: > >http://www.tricountyi.net/~randerse/regen.htm > >If I inject a signal directly into the coil (in place of his amplified RF "front >stage") I can pick it up, but no oscillation and lousy tuning. (comes in on pretty >much 1/2 the dial) I'm assuming this has something to do with the tank circuit. (I have >two air capacitors totalling around 360pf one from a console stereo, the other from >some place I can't remember where..) > >He's got 25T and 23T specified for a T-50-2 coil. Closest research on these that >I can find is that this should produce about 300mh (but I could be wrong! anyone know >for sure what the mH is on that?) This seems to make sense from everything I've read >so far, but.. I have no way to measure it. 23-25 turns (or 50 total) on a T50-2 would be more like 20 uH (micro henries). If you using a ferite intended for noise suppression then its likely 43 ot 71 material and not suited for RF tuned circuits. >If I end up using an air core, would I keep the ratio of turns for the tickler and >injection coil? (where he has 3 and 5 turns spec'd) ? It's my assumption that >in these two smaller coils, it's a step up transformer so it'd be a matter of ratios, >am I correct in this assumption? > >Every bit of the circuit should come from garbage (the MPF102's I had to buy, but thats >it) Even the coil wire is from the transformer of a broken microwave, the LM386 chip used >for audio (and some resistors) will come from an old modem and the pot is a 500k pot, >(from a console) wired in parallel with a ~>10k resistor to give a range between 0 - 10k ohms. > >The main point is to build it from garbage, I already have a radio and don't >really "need" one, but.. as I once built a tube version of this (far simpler) >doing one in solid state appeals to me. Why not wind the coil on a toilet paper cardboard tube, pill bottle, or peice of PVC pipe scrap? Allison > >Jamie Article: 98055 of rec.radio.amateur.homebrew Date: Fri, 14 Jul 2006 07:32:13 -0700 From: Tim Wescott Subject: Re: toroid cores? References: Message-ID: Jamie wrote: > Hi Newsgroup, > > Been trying to make a regen radio out of garbage. So far, I seem to have > all the parts and it almost seems to work, however, I'm a bit confused > about the inductance of toroid cores. > > I've tried to use one of those things from the back of a monitor (presumably > to prevent RF interference) as one of the coils and another adjustable coil > from another device, to no avail. It has no markings and it appears to be > a ferrite device in the shape of a ring. > > Anyone know an easy way to figure out how many turns to get (presumably 300mh?) > from one of these? Can I measure it with a ruler and some how get a formula > for the number of turns / mH ? Are these really bad deviced to use? (the thought > occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) > > Here's the circuit I'm basing it on: > > http://www.tricountyi.net/~randerse/regen.htm > > If I inject a signal directly into the coil (in place of his amplified RF "front > stage") I can pick it up, but no oscillation and lousy tuning. (comes in on pretty > much 1/2 the dial) I'm assuming this has something to do with the tank circuit. (I have > two air capacitors totalling around 360pf one from a console stereo, the other from > some place I can't remember where..) > > He's got 25T and 23T specified for a T-50-2 coil. Closest research on these that > I can find is that this should produce about 300mh (but I could be wrong! anyone know > for sure what the mH is on that?) This seems to make sense from everything I've read > so far, but.. I have no way to measure it. > > If I end up using an air core, would I keep the ratio of turns for the tickler and > injection coil? (where he has 3 and 5 turns spec'd) ? It's my assumption that > in these two smaller coils, it's a step up transformer so it'd be a matter of ratios, > am I correct in this assumption? > > Every bit of the circuit should come from garbage (the MPF102's I had to buy, but thats > it) Even the coil wire is from the transformer of a broken microwave, the LM386 chip used > for audio (and some resistors) will come from an old modem and the pot is a 500k pot, > (from a console) wired in parallel with a ~>10k resistor to give a range between 0 - 10k ohms. > > The main point is to build it from garbage, I already have a radio and don't > really "need" one, but.. as I once built a tube version of this (far simpler) > doing one in solid state appeals to me. > > Jamie There are toroid cores that would work quite well for this, but the characteristics of the core depend heavily on the core material. It can be very difficult to characterize a mystery core. I suggest you look in the ARRL handbook for the appropriate coil formula (or search the web) and make a single-layer air core coil on an appropriate-sized form. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Posting from Google? See http://cfaj.freeshell.org/google/ "Applied Control Theory for Embedded Systems" came out in April. See details at http://www.wescottdesign.com/actfes/actfes.html Article: 98056 of rec.radio.amateur.homebrew Message-ID: References: <1152877367.450775.256530@h48g2000cwc.googlegroups.com> Subject: Re: toroid cores? From: nospam@geniegate.com (Jamie) Date: Fri, 14 Jul 2006 14:49:48 GMT In , Tim Wescott mentions: >skavanagh72nospam@yahoo.ca wrote: >> Jamie wrote: >> >> >>>I've tried to use one of those things from the back of a monitor (presumably >>>to prevent RF interference) as one of the coils and another adjustable coil >>>from another device, to no avail. It has no markings and it appears to be >>>a ferrite device in the shape of a ring. >>> >>>Anyone know an easy way to figure out how many turns to get (presumably 300mh?) >>>from one of these? Can I measure it with a ruler and some how get a formula >>>for the number of turns / mH ? Are these really bad deviced to use? (the thought >>>occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) >> >> >> Yes, I would expect they would be really bad ! If you knew the >> permeability of the material used then measuring with a ruler and >> applying some math (I don't know the formulas) would in theory get you >> an iductance calculation. But the materials used for these EMI chokes >> generally has too high a permeability to make inductors with convenient >> numbers of turns for the HF bands, and generally is quite lossy so the >> resulting inductors will have low Q. It is extremely unlikely to work. >> >> Since you don't want to buy any parts, I would recommend once you >> figure out the required inductance from the Amidon formulas, just wind >> air core coils (well, some sort of low loss former like a piece of >> plastic tubing is probably needed) with the same inductance. >> Inductance formulas for air core coils are available everywhere in >> handbooks and on the web. You might have to play with the number of >> turns in the feedback link though, as the coupling between it and the >> main coil will not be as tight in an air core coil as in the toroid. I >> would start with the same ratio of turns or maybe add a bit to the >> feedback coil. >> >> 73, >> Steve VE3SMA >> >If it's a broadcast band radio a toilet paper tube will work well. If >ham band then something smaller like a sample-size shampoo bottle. > >Does it count as garbage if you buy the stuff so you'll have the >'garbage' when you're done? LOL! I was sooo tempted to buy 0.05 resistors after burning my fingers trying to extract them from a modem.. :-) I read some place, it's better to use a larger diameter coil if at all possible, but the formulas I've run across for calculating uH (I always get my milli's and micros confused!) seem to indicate in either case, I'd need the same amount of wire. Lots of things puzzle me about this, for example in this circuit: http://www.tricountyi.net/~randerse/regen.htm I don't see a "grid leak" the way I had used in the tube model. While this circuit: http://www.electronics-tutorials.com/receivers/regen-radio-receiver.htm Seems to have one feeding the gate of the FET. (never was real clear on what it did exactly) (I can't use the latter circuit as it has more parts and I don't want to introduce a 3rd variable cap.) Jamie -- http://www.geniegate.com Custom web programming guhzo_42@lnubb.pbz (rot13) User Management Solutions Article: 98057 of rec.radio.amateur.homebrew From: "Reg Edwards" References: Subject: Re: toroid cores? Date: Fri, 14 Jul 2006 16:13:06 +0100 Message-ID: The inductance of a toroid, in MICRO-henries, is - L = 0.6283 * Mu * Square( N ) * B where B = D1 - Squareroot( Square( D1) - Square( D2 ) ) Mu = permeability of core material. N = number of turns. D1 = mean diameter of ring in metres. D2 = diameter of ferrite core material in metres. If the core is not circular, use the equivalent diameter which has the same cross-sectional area. To calculate number of turns just rearrange the formula. To obtain high Q, you MUST use HF grade permeability material. Permeability can be calculated using the formula by winding some turns on a core and measuring inductance. A very good instrument to use is an Autek RF Analyst-1 But, of course, if you are able to measure inductance there will be no need to calculate permeability. You can calculate the required number of turns immediately. ---- Reg. Article: 98058 of rec.radio.amateur.homebrew Message-ID: References: Subject: Re: toroid cores? From: nospam@geniegate.com (Jamie) Date: Fri, 14 Jul 2006 15:24:16 GMT In , Scott mentions: >Check this page from Amidon Associates. They are a great supplier of >toroids to the ham community! > >http://www.amidoncorp.com/aai_ironpowdercores.htm > >Looks to me like 25 turns on a T-50-2 core will give about 3 MICRO >Henries according to Amidon's formula... Whew! thanks! My assumption that it was 300 yielded some pretty far out number of turns for air coils, like 72 or something I seem to recall. Looks more like 7-8 turns on a cylinder 2.5" in diameter? (that seems awful small to me) If the tickler coil is currently three turns, would I just leave it at that? Still, it's nice.. small enough I can probably use the "good wire" for shortwave. :-) (FWIW old microwaves are apparently an excellent source if copper wire, I'm tempted to use some of it for an antenna) If the capacitance in the tank circuit is ~25-400pF, and I use 3uH then the frequency response will be about: 4.5mhz - 14mhz ? (does that sound right?) This must be why the others I'd looked at involve pluggable or tapped coils? (In general, is there an ideal ratio of capacitance to inductance for a given range? IE: could I just add parallel capacitance to lower the frequency or is it better to increase the coil or.. both? I notice as I run through some calculations, I need a LOT more uH to cover a smaller and smaller range of frequencies the lower I get. He states on his page that it picks up MW, (which is actually what I'm mostly interested in) but.. didn't mention anything about mixed coils. His circuit involves a "front end RF amp" (for a total of two coils) when using air, do I need to some how shield this second coil? I'm assuming it if it's perpendicular to the main one, thats enough?) Was hoping to avoid a large air coil because as it is now, the everything except the capacitors (and AF stuff) fit in a tunafish can for shielding. :-/ Still, the whole point is to assemble it from garbage. I might splurge and get some mechanical stuff for the tuner, but.. have to get it working first! (sure am glad I kept that signal injector, it's been really handy for this!) Jamie -- http://www.geniegate.com Custom web programming guhzo_42@lnubb.pbz (rot13) User Management Solutions Article: 98059 of rec.radio.amateur.homebrew From: John - KD5YI Subject: Re: toroid cores? References: <309fb21i39n8qlhrrnobbpj5jc1u26pq5s@4ax.com> Message-ID: Date: Fri, 14 Jul 2006 16:05:42 GMT nospam@nouce.bellatlantic.net wrote: > On Fri, 14 Jul 2006 09:42:06 GMT, nospam@geniegate.com (Jamie) wrote: > > >>Hi Newsgroup, >> >>Been trying to make a regen radio out of garbage. So far, I seem to have >>all the parts and it almost seems to work, however, I'm a bit confused >>about the inductance of toroid cores. >> >>I've tried to use one of those things from the back of a monitor (presumably >>to prevent RF interference) as one of the coils and another adjustable coil > >>from another device, to no avail. It has no markings and it appears to be > >>a ferrite device in the shape of a ring. >> >>Anyone know an easy way to figure out how many turns to get (presumably 300mh?) > >>from one of these? Can I measure it with a ruler and some how get a formula > >>for the number of turns / mH ? Are these really bad deviced to use? (the thought >>occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) >> >>Here's the circuit I'm basing it on: >> >>http://www.tricountyi.net/~randerse/regen.htm >> >>If I inject a signal directly into the coil (in place of his amplified RF "front >>stage") I can pick it up, but no oscillation and lousy tuning. (comes in on pretty >>much 1/2 the dial) I'm assuming this has something to do with the tank circuit. (I have >>two air capacitors totalling around 360pf one from a console stereo, the other from >>some place I can't remember where..) >> >>He's got 25T and 23T specified for a T-50-2 coil. Closest research on these that >>I can find is that this should produce about 300mh (but I could be wrong! anyone know >>for sure what the mH is on that?) This seems to make sense from everything I've read >>so far, but.. I have no way to measure it. > > > 23-25 turns (or 50 total) on a T50-2 would be more like 20 uH > (micro henries). Hi, Allison - I think you erred slightly. It's about 3 uH at 25 turns on a T-50-2. See Scott's post in this thread for a link to data and equation. Cheers, John Article: 98060 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: toroid cores? Message-ID: References: <309fb21i39n8qlhrrnobbpj5jc1u26pq5s@4ax.com> Date: Fri, 14 Jul 2006 16:41:04 GMT On Fri, 14 Jul 2006 16:05:42 GMT, John - KD5YI wrote: >nospam@nouce.bellatlantic.net wrote: >> On Fri, 14 Jul 2006 09:42:06 GMT, nospam@geniegate.com (Jamie) wrote: >> >> >>>Hi Newsgroup, >>> >>>Been trying to make a regen radio out of garbage. So far, I seem to have >>>all the parts and it almost seems to work, however, I'm a bit confused >>>about the inductance of toroid cores. >>> >>>I've tried to use one of those things from the back of a monitor (presumably >>>to prevent RF interference) as one of the coils and another adjustable coil >> >>>from another device, to no avail. It has no markings and it appears to be >> >>>a ferrite device in the shape of a ring. >>> >>>Anyone know an easy way to figure out how many turns to get (presumably 300mh?) >> >>>from one of these? Can I measure it with a ruler and some how get a formula >> >>>for the number of turns / mH ? Are these really bad deviced to use? (the thought >>>occurs I must admit, that if it was meant to BLOCK rf, using would be illogical) >>> >>>Here's the circuit I'm basing it on: >>> >>>http://www.tricountyi.net/~randerse/regen.htm >>> >>>If I inject a signal directly into the coil (in place of his amplified RF "front >>>stage") I can pick it up, but no oscillation and lousy tuning. (comes in on pretty >>>much 1/2 the dial) I'm assuming this has something to do with the tank circuit. (I have >>>two air capacitors totalling around 360pf one from a console stereo, the other from >>>some place I can't remember where..) >>> >>>He's got 25T and 23T specified for a T-50-2 coil. Closest research on these that >>>I can find is that this should produce about 300mh (but I could be wrong! anyone know >>>for sure what the mH is on that?) This seems to make sense from everything I've read >>>so far, but.. I have no way to measure it. >> >> >> 23-25 turns (or 50 total) on a T50-2 would be more like 20 uH >> (micro henries). > > >Hi, Allison - > >I think you erred slightly. It's about 3 uH at 25 turns on a T-50-2. See >Scott's post in this thread for a link to data and equation. For 23-25 yes, but I also postulated that was a tapped coil of 50T total. then I'm closer. But it was an eyeball guess as I didn't calculate it. I was only off by ~7 rather than 10,000. ;) Allison > >Cheers, >John Article: 98061 of rec.radio.amateur.homebrew From: "AAA RF Products" Subject: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 each. Message-ID: Date: Fri, 14 Jul 2006 12:07:03 -0700 For Sale: Finest quality PL-259's silver plated contact & body, Teflon insulation, nickel plated coupling nut. Unlimited quantity available. 1 to 99 ------ $1.67 each 100 to 499----$1.50 each 500+----------$1.40 each Immediate shipment, FOB: San Clemente, CA No minimum order. No handling charges. Please email sales@AAARFProducts.com or call 949 481 3154 (San Clemente, CA, USA) See our catalog @ www.aaarfproducts.com Article: 98062 of rec.radio.amateur.homebrew From: "Steve N." Subject: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes Date: Fri, 14 Jul 2006 16:22:20 -0500 Message-ID: References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> "Highland Ham" wrote in message news:kaSdnXVj7qGf4irZRVny2w@pipex.net... > > I knew that I already had two phases in the guest room. > > A couple of cheap extension cords was all it took, with one blade of a > > "three prong adaprer" inserted into each hot side of each extension. Guest > > 220 in 5 minutes! > > > > I'd feel ok drawing 8A this way, but you shouldn't try this at home...I'm a > > professional. (:-) > > > > Linears should have either > > 1- both 110 and 220 internal wiring options, or > > 2- just 220 > > > > But 120 is is a real stretch. > ====================== > Steve , Tnx for providing the 'full' picture. > Assuming a 67 percent efficiency (am I too pessimistic?) a legal RF > power amp would need 1.5*1500 = 2250 W (say overall maximum of 2400W) > which at 220 V means 12 Amperes. > So, a shack without 220 -234 V power supply would need a dedicated > supply from the switchboard . > > Here in the UK we do have 115V industrial power tools,which need to be > used with a 230/115V (usually portable) safety transformer with the > secondary having an earthed centre tap ,such that in the event of a > 'fault' personnel is exposed to a (peak) voltage not exceeding 1.4*58 = > 81V which is considered sufficiently low to prevent electrocution. > > The nominal domestic supply voltage within EU countries has now been > 'normalised' to 230V ,meaning that (within a voltage band) the same > equipment can be used in all the countries. > Before , the UK had 240V and continental countries 220V . This often > meant that for example an (clothing) iron for 220 V had a very limited > life when used in Britain . > The voltage at my place (rural area) is nowadays usually 236-237 V > ,whereas earlier it was up to 250 V or sometimes even higher. > > Frank GM0CSZ / KN6WH In the cell phone base business, everything (almost) runs off battery systems. There were two cases where Development Engineers not knowing about our mains system, where developing products never before run off the mains. In one, the presence of "both" 120 and 240 was causing some spike absorbers, designed for 120 systems, to pop from the 240. The other was a small base station which had its power input connections designed by Mechanical engineers. It came to my test group without the power cord connected to the black (protorype) "barrier terminal strip". One of the Develpoment Engineers called another for the connections and made them. It was plugged in, but wouldn't work. Several Engineers started checking and discuvered that the serial port on the control laptop had been fried. Several of us put our noses to the connector and could smell the burned components on the unit. We also noticed that the heat sink wasn't getting warm. I and several Engineers put our hands on the case to test this. Note: In the US, we have a third wire in all outlets which, though it is the same as the common or neutral (basically also ground or no potential) side, it is used to connect to any exposed metal parts. The purpose it to divert any hahazzardous shorts to ground and blow a breaker or fuse rather than harming someone. We were focused on finding the cause. Several of us worked trying to analyxe the failure and found the serial interface of the unit has fried as well as the lap top serial port. Findings: The HOT of the 120 ( instead of the safety ground connection) was connected to the chassis. This placed the outside of the (as yet unpainted) housing at 120 VAC relative to all other grounded equipment in the room! I was one of several who put his nose up to that hole to smell burnt comopnents. I was one who felt the unit for heat build up. It hit me half way home. Needledd to say, I gave the Mechanical and Electrical Engineers a lecture on mains principles. 73, Steve, K9DCI Article: 98063 of rec.radio.amateur.homebrew Message-ID: <44B82329.9F41DD33@earthlink.net> From: "Michael A. Terrell" Subject: Re: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> Date: Fri, 14 Jul 2006 23:05:42 GMT "Steve N." wrote: > > If you really need to get 220 quickly and easily [ and do not draw more than > than the 15 or 20 amps of your brealers] you can find two outlets on the > two phases and get one half of the 220 from each. > I did this for a visiting relative from Germany so he could run his electric > shaver. It is still the talk of the relatives... > Since I built my house and did the wiring with Dad's help, I kept a drawing > of all the circuits, I knew that I already had two phases in the guest room. > A couple of cheap extension cords was all it took, with one blade of a > "three prong adaprer" inserted into each hot side of each extension. Guest > 220 in 5 minutes! Using two outlets without some logic to make sure both plugs are connected is a very dangerous setup. The simplest setup is three relays, two to detect the 120 VAC on each cord that together energize the 240 VAC outlet. -- 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: 98064 of rec.radio.amateur.homebrew From: "W3JDR" References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes Message-ID: Date: Sat, 15 Jul 2006 01:30:57 GMT >The other was a small base station which had its power input connections >designed by Mechanical engineers. ----------------------- I wouldn't blame the mechanical engineers. I'd blame the engineering manager who let mechanical engineers design an electrical interface, and then apparently didn't design-review it. Joe W3JDR "Steve N." wrote in message news:e991uc$n7n$1@avnika.corp.mot.com... > > "Highland Ham" wrote in message > news:kaSdnXVj7qGf4irZRVny2w@pipex.net... >> > I knew that I already had two phases in the guest room. >> > A couple of cheap extension cords was all it took, with one blade of a >> > "three prong adaprer" inserted into each hot side of each extension. > Guest >> > 220 in 5 minutes! >> > >> > I'd feel ok drawing 8A this way, but you shouldn't try this at > home...I'm a >> > professional. (:-) >> > >> > Linears should have either >> > 1- both 110 and 220 internal wiring options, or >> > 2- just 220 >> > >> > But 120 is is a real stretch. >> ====================== >> Steve , Tnx for providing the 'full' picture. >> Assuming a 67 percent efficiency (am I too pessimistic?) a legal RF >> power amp would need 1.5*1500 = 2250 W (say overall maximum of 2400W) >> which at 220 V means 12 Amperes. >> So, a shack without 220 -234 V power supply would need a dedicated >> supply from the switchboard . >> >> Here in the UK we do have 115V industrial power tools,which need to be >> used with a 230/115V (usually portable) safety transformer with the >> secondary having an earthed centre tap ,such that in the event of a >> 'fault' personnel is exposed to a (peak) voltage not exceeding 1.4*58 = >> 81V which is considered sufficiently low to prevent electrocution. >> >> The nominal domestic supply voltage within EU countries has now been >> 'normalised' to 230V ,meaning that (within a voltage band) the same >> equipment can be used in all the countries. >> Before , the UK had 240V and continental countries 220V . This often >> meant that for example an (clothing) iron for 220 V had a very limited >> life when used in Britain . >> The voltage at my place (rural area) is nowadays usually 236-237 V >> ,whereas earlier it was up to 250 V or sometimes even higher. >> >> Frank GM0CSZ / KN6WH > > > > In the cell phone base business, everything (almost) runs off battery > systems. > There were two cases where Development Engineers not knowing about our > mains > system, where developing products never before run off the mains. > In one, the presence of "both" 120 and 240 was causing some spike > absorbers, > designed for 120 systems, to pop from the 240. > > The other was a small base station which had its power input connections > designed by Mechanical engineers. It came to my test group without the > power cord connected to the black (protorype) "barrier terminal strip". > One > of the Develpoment Engineers called another for the connections and made > them. It was plugged in, but wouldn't work. Several Engineers started > checking and discuvered that the serial port on the control laptop had > been > fried. Several of us put our noses to the connector and could smell the > burned components on the unit. We also noticed that the heat sink wasn't > getting warm. I and several Engineers put our hands on the case to test > this. > Note: In the US, we have a third wire in all outlets which, though it is > the same as the common or neutral (basically also ground or no potential) > side, it is used to connect to any exposed metal parts. The purpose it > to > divert any hahazzardous shorts to ground and blow a breaker or fuse rather > than harming someone. We were focused on finding the cause. Several of > us > worked trying to analyxe the failure and found the serial interface of the > unit has fried as well as the lap top serial port. > Findings: > The HOT of the 120 ( instead of the safety ground connection) was > connected > to the chassis. This placed the outside of the (as yet unpainted) housing > at 120 VAC relative to all other grounded equipment in the room! > I was one of several who put his nose up to that hole to smell burnt > comopnents. I was one who felt the unit for heat build up. > > It hit me half way home. Needledd to say, I gave the Mechanical and > Electrical Engineers a lecture on mains principles. > > 73, Steve, K9DCI > > Article: 98066 of rec.radio.amateur.homebrew From: bill.meara@gmail.com Subject: SolderSmoke #27: HI8 trip, Books, Ether, Quantums, Xtal Osc Design and build Date: 15 Jul 2006 01:54:38 -0700 Message-ID: <1152953678.181115.294510@75g2000cwc.googlegroups.com> SolderSmoke! A SHOW FOR ELECTRONICS HOMEBREWERS! http://www.ourmedia.org/node/247756 Topics discussed in SolderSmoke #27: -- Computer woes -- Bill's visit to the Dominican Republic -- Building Xtal oscillator with kid -- Book Reviews: "The Art of Electronics" "The Electronics of Radio" -- Ether and Quantum Mechanincs, Tao of Physics -- SolderSmoke Mailbag: Nigel in Dover, Mike WA6AWA, Matt KC8COM CHECK OUT A PICTURE OF SOLDERSMOKE'S LONDON STUDIO: http://usgadgeteer.blogspot.com/ Listen at: http://www.ourmedia.org/node/247756 Background: Tired of listening to Led Zepplin or NPR on your I-Pod? Wouldn't you like to be able to carry with you the kinds of ham radio conversations that you listen to while in your radio shack? Mike, KL7R, in Juneau, Alaska, and Bill, M0HBR, in London, England meet regularly on the ECHOLINK system to discuss their homebrew radio projects. We are making them available as PODCASTS. NEW RSS FEED: You can subscribe to the program, have them downloaded to your MP-3 player, and listen to them at your convenience. To subscribe, just cut and paste this URL into your I-poder (or similar) software. We've been having trouble with our Ourmedia RSS feed, so Mike (software wizard that he is) has homebrewed his own RSS feed. In order to subscribe to SolderSmoke, point your podcast software to: http://kl7r.ham-radio.ch/soldersmoke.rss If you don't have an MP3 player you can just go to the site below and listen to the latest program (and earlier editions) using the audio software on your computer. http://www.ourmedia.org/node/247756 Here's the homepage for our show. All our programs are available here. There is also a blog and links to some of the sites and documents we've been discussing: http://www.ourmedia.org/user/36170 We hope you enjoy the program. Please send us feedback. 73 from London Bill M0HBR N2CQR CU2JL http://www.gadgeteer.us Article: 98067 of rec.radio.amateur.homebrew From: Paul Keinanen Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes Message-ID: <5amib2thgqnfmg6dsmtbcol3t0m0v418q9@4ax.com> References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> Date: Sun, 16 Jul 2006 01:06:05 +0300 On Fri, 14 Jul 2006 16:22:20 -0500, "Steve N." wrote: >The HOT of the 120 ( instead of the safety ground connection) was connected >to the chassis. This placed the outside of the (as yet unpainted) housing >at 120 VAC relative to all other grounded equipment in the room! >I was one of several who put his nose up to that hole to smell burnt >comopnents. I was one who felt the unit for heat build up. If you get an electric shock in your nose, I would suggest that you do not drive a car for a few hours. I was building a power supply and fired it up for the first time and was sniffing for any hot components. I then actually hit the hot side of the power transformer primary terminal (220 V over here in those days). It was a nasty shock and when driving the car soon after, I really had to concentrate to keep the car in the middle of the lane:-). Paul OH3LWR Article: 98068 of rec.radio.amateur.homebrew Subject: ** FLEA at MIT ** Sunday July 16th Cambridge MA From: w1gsl@mit.edu (Steven L. Finberg) Date: 15 Jul 2006 22:31:05 GMT Message-ID: <44b96ca9$0$560$b45e6eb0@senator-bedfellow.mit.edu> This comming Sunday... +++ Now even more Buyers Parking !!! Thanks to Shire we have use of their new parking lot across Albany St from the SWAPFEST !!! !! ** More Buyers PARKING is available ** for details see http://web.mit.edu/w1gsl/Public/flyer *** !!!! In our Traditional GARAGE and the adjacent lot !!!! **** so come rain or shine or super heat the Flea is on !!! ********* $1 buyers discount with hardcopy of this notice ******** COMPUTERS - ELECTRONICS - HAM RADIO - COMPUTERS - ELECTRONICS - HAM RADIO FLEA all SUMMER at MIT Sunday July 16th 2006 9AM-2PM Come to the city for a great flea - plenty of free parking. MIT's electronics and ham radio flea will take place on the third Sunday of each month this summer, April thru October. There is tailgate space for over 600 sellers and free, off-street parking for >2000 cars! Buyers admission is $5 (you get $1 off if you're lucky enough to have a copy of our ad) and sellers spaces are $20 for the first and $15 for each additional at the gate. The flea will be held at the corner of Albany and Main streets in Cambridge; right in the Kendall Square area from 9AM to 2PM, with sellers set-up time starting at 7AM. SEASON PASS + Advance Seller Discount A sellers discount season pass is available which offers a 30% discount. By prepaying you get a discount and earlier admission. See the registration form. *** Attention Sellers *** Prepaid vendors.. Season Pass or monthly, will be admitted FIRST. Separate lines will form prior to gate opening for prepaid and nonprepaid vendors !! RAIN or SHINE !! Have no fear of rain, a covered well illuminated tailgate area is available for all sellers (6'8" clearance). Talk-in: 145.23- (PL 88.5) W1BOS/R and W1XM/R-449.725/444.725 (PL 114.8/2A). Sponsors: MIT Electronics Research Society MIT UHF Repeater Association (W1XM) MIT Radio Society (W1MX) Harvard Wireless Club (W1AF) For more info / advanced reservations 617 253 3776 ********** $1 buyers discount with hard copy of this notice ************ <<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Mail the coupon below by the 5th of the month to be a Prepaid Vendor. FLEA at MIT 2006 Rates SELLERS To use your prepaid spaces the named vendor MUST be present. Rates include one admission per space. Season Pass $99 First Space includes all 7 2006 meets $70 each additional Space Must be received by April 16th Advance $17 First space $12 Additional Spaces Must be received by the 5th of the month. Gate Admission $20 First Space $15 Additional Spaces Admission is after the prepaid vendors Early Bird Buyer -Admission after the prepaid vendor line is admitted. ~ 7:15AM ** You may not sell. ** $15 per person at the gate. ****************************** cut here ******************************* FLEA at MIT 2006 Advance Space Application ____April ____May ____June ____ July ____Aug ___Sept ____Oct @ $17 for the first each month + $12 each additional ____ Season Pass @$99 _____ Additional Season Spaces @$70 Name ________________________ Call __________ $ Included______ Address ________________________ Phone __________ Make Check to The MIT Radio Society City ____________________ State _______ Zip _______ PO Box 397082 Cambridge MA 02139 E-mail _____________________________________________ ******************************************************************************* Steve Finberg W1GSL w1gsl@mit.edu PO Box 82 MIT Br Cambridge MA 02139-7082 617 258 3754 ******************************************************************************* Article: 98069 of rec.radio.amateur.homebrew Message-ID: Date: Sun, 16 Jul 2006 10:12:15 +0100 From: Ian White GM3SEK Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> Paul Keinanen wrote: >I was building a power supply and fired it up for the first time and >was sniffing for any hot components. I then actually hit the hot side >of the power transformer primary terminal (220 V over here in those >days). It was a nasty shock Well don't DO that! (But I'm a fine one to talk: my bad habit is to sniff the soldering iron to see if it's hot :-) -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek Article: 98070 of rec.radio.amateur.homebrew Date: Sun, 16 Jul 2006 13:06:47 +0000 From: Scott Subject: Re: toroid cores? References: Message-ID: Well, I'm not sure about a lot of the questions you asked, so I would suggest waiting to hear from others for ideas or, in true hamming spirit, give it a go and see what happens :) I wish you good luck...it sounds like an interesting project! Scott N0EDV Jamie wrote: > In , > Scott mentions: > >>Check this page from Amidon Associates. They are a great supplier of >>toroids to the ham community! >> >>http://www.amidoncorp.com/aai_ironpowdercores.htm >> >>Looks to me like 25 turns on a T-50-2 core will give about 3 MICRO >>Henries according to Amidon's formula... > > > Whew! thanks! > > My assumption that it was 300 yielded some pretty far out number of turns > for air coils, like 72 or something I seem to recall. > > Looks more like 7-8 turns on a cylinder 2.5" in diameter? (that seems > awful small to me) If the tickler coil is currently three turns, would I > just leave it at that? Still, it's nice.. small enough I can probably use > the "good wire" for shortwave. :-) (FWIW old microwaves are apparently an > excellent source if copper wire, I'm tempted to use some of it for an > antenna) > > If the capacitance in the tank circuit is ~25-400pF, and I use 3uH then > the frequency response will be about: 4.5mhz - 14mhz ? (does that sound > right?) > > This must be why the others I'd looked at involve pluggable or tapped coils? > > (In general, is there an ideal ratio of capacitance to inductance for a given > range? IE: could I just add parallel capacitance to lower the frequency > or is it better to increase the coil or.. both? I notice as I run through > some calculations, I need a LOT more uH to cover a smaller and smaller range > of frequencies the lower I get. > > He states on his page that it picks up MW, (which is actually what I'm mostly > interested in) but.. didn't mention anything about mixed coils. > > His circuit involves a "front end RF amp" (for a total of two coils) when > using air, do I need to some how shield this second coil? I'm assuming it > if it's perpendicular to the main one, thats enough?) > > Was hoping to avoid a large air coil because as it is now, the everything > except the capacitors (and AF stuff) fit in a tunafish can for shielding. :-/ > > Still, the whole point is to assemble it from garbage. I might splurge and > get some mechanical stuff for the tuner, but.. have to get it working first! > (sure am glad I kept that signal injector, it's been really handy for this!) > > Jamie Article: 98071 of rec.radio.amateur.homebrew From: "Roger" Subject: Re: ** FLEA at MIT ** Sunday July 16th Cambridge MA Date: Sun, 16 Jul 2006 09:24:29 -0400 Message-ID: <5a41t.24s.19.1@news.alt.net> References: <44b96ca9$0$560$b45e6eb0@senator-bedfellow.mit.edu> A collection of *Non Ham Radio* Junk, attended by CBers and white trash. Article: 98072 of rec.radio.amateur.homebrew From: "Dexxsterlab" Subject: Re: YAESU FT-817 FT-857 FT-897 KEYPAD Date: Sun, 16 Jul 2006 15:34:54 +0200 Message-ID: <44ba407e$0$30141$4fafbaef@reader4.news.tin.it> A keypad for your Yaesu FT-8x7 transceiver http://www.dexxsterlab.com/kp8x7/kp8x7e.pdf http://www.qsl.net/it9xxs Article: 98073 of rec.radio.amateur.homebrew Date: Sun, 16 Jul 2006 15:00:27 +0100 From: Highland Ham Subject: Re: ** FLEA at MIT ** Sunday July 16th Cambridge MA References: <44b96ca9$0$560$b45e6eb0@senator-bedfellow.mit.edu> <5a41t.24s.19.1@news.alt.net> Message-ID: <8pKdnXu4Cczy2yfZnZ2dnUVZ8smdnZ2d@pipex.net> Roger wrote: > A collection of *Non Ham Radio* Junk, attended by CBers > and white trash. ============================ What's your problem ? You might even meet a few ham radio operators. As far as CBers are concerned .........live and let live. Frank GM0CSZ / KN6WH Article: 98074 of rec.radio.amateur.homebrew Message-ID: <8PS9IMRMOmuEFANF@ifwtech.co.uk> Date: Sun, 16 Jul 2006 17:04:28 +0100 From: Ian White GM3SEK Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> Michael A. Terrell wrote: >Ian White GM3SEK wrote: >> >> (But I'm a fine one to talk: my bad habit is to sniff the soldering iron >> to see if it's hot :-) > > > At least you stopped using your tongue to test it! ;-) > No, you've got it all wrong - you use your tongue to test if the soldering iron is COLD. -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek Article: 98075 of rec.radio.amateur.homebrew From: "Roger" Subject: Re: ** FLEA at MIT ** Sunday July 16th Cambridge MA Date: Sun, 16 Jul 2006 13:03:52 -0400 Message-ID: <5agt9.ihp.19.1@news.alt.net> References: <44b96ca9$0$560$b45e6eb0@senator-bedfellow.mit.edu> <5a41t.24s.19.1@news.alt.net> <8pKdnXu4Cczy2yfZnZ2dnUVZ8smdnZ2d@pipex.net> "Highland Ham" wrote in message news:8pKdnXu4Cczy2yfZnZ2dnUVZ8smdnZ2d@pipex.net... > Roger wrote: >> A collection of *Non Ham Radio* Junk, attended by CBers >> and white trash. > ============================ > What's your problem ? You might even meet a few ham radio operators. > As far as CBers are concerned .........live and let live. > > Frank GM0CSZ / KN6WH Only problem is when people like you make idiotic statements like you just did. Get a reality check. Article: 98076 of rec.radio.amateur.homebrew From: "JeffM" Subject: [SPAM] Some people refuse to learn from their errors Date: 16 Jul 2006 11:25:33 -0700 Message-ID: <1153074333.126707.117090@35g2000cwc.googlegroups.com> References: was: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 each. AAA RF Products wrote: >[SPAM SPAM SPAM SPAM] http://groups.google.com/group/sci.electronics.components/browse_frm/thread/e3786ad39814b5f6/9db691e887340175?q=a-lot-of-ill-will+zzz+SPAM+qq+your-inappropriate-attempts-at-advertising+scumbag Article: 98077 of rec.radio.amateur.homebrew From: "an_old_friend" Subject: Re: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 each. Date: 16 Jul 2006 19:03:43 -0700 Message-ID: <1153101822.957736.32090@m79g2000cwm.googlegroups.com> References: AAA RF Products wrote: > For Sale: Finest quality PL-259's silver plated contact & body, Teflon > insulation, nickel plated coupling nut. Unlimited quantity available. > > 1 to 99 ------ $1.67 each > > 100 to 499----$1.50 each > > 500+----------$1.40 each > > Immediate shipment, FOB: San Clemente, CA > > No minimum order. > > No handling charges. > > Please email sales@AAARFProducts.com > > or call 949 481 3154 (San Clemente, CA, USA) > > See our catalog @ www.aaarfproducts.com spam perhaps but at least it is better than most of the posting these days Article: 98078 of rec.radio.amateur.homebrew From: "kb9rqz@hotmail.com" Subject: Re: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 each. Date: 16 Jul 2006 19:47:04 -0700 Message-ID: <1153104424.497450.62710@m73g2000cwd.googlegroups.com> References: Michael A. Terrell wrote: > an_old_friend wrote: > > > > AAA RF Products wrote: > > > For Sale: Finest quality PL-259's silver plated contact & body, Teflon > > > insulation, nickel plated coupling nut. Unlimited quantity available. > > > > > > 1 to 99 ------ $1.67 each > > > > > > 100 to 499----$1.50 each > > > > > > 500+----------$1.40 each > > > > > > Immediate shipment, FOB: San Clemente, CA > > > > > > No minimum order. > > > > > > No handling charges. > > > > > > Please email sales@AAARFProducts.com > > > > > > or call 949 481 3154 (San Clemente, CA, USA) > > > > > > See our catalog @ www.aaarfproducts.com > > spam perhaps but at least it is better than most of the posting these > > days > > > Look at the crappy no name coax and super cheap connectors on their > website before you decide anything. BTW, they have a very bad > attitude. One of their salesmen was on one of the sci.electronics > groups telling people off. why should I I just did not care for the action of another in trying to jam a post that yea is spam is at least ontopic instead all the posters trying to make issues out of people sexlife his product can be totaltrash but total trashis better than a post that consists entily of "you are faggot" as many post here do you don't like his product don't buy it > > > -- > 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: 98079 of rec.radio.amateur.homebrew Message-ID: References: Subject: Re: toroid cores? From: nospam@geniegate.com (Jamie) Date: Mon, 17 Jul 2006 04:22:34 GMT In , Scott mentions: >Well, I'm not sure about a lot of the questions you asked, so I would >suggest waiting to hear from others for ideas or, in true hamming >spirit, give it a go and see what happens :) > >I wish you good luck...it sounds like an interesting project! Thanks. Looks like I may have fried the FET. :-( No matter what I did, I simply could not get feedback. I hooked an LM368 audio amp pretty much directly to the RF signal generator and I could vaguely hear it, so... I'm thinking the reason it was working the way it did (with the "station" comming in stronger as I tuned it) was simply the LM386 acting like a detector in a TRF radio :-/ (The thing that confused me was, if I held an AM radio really close to the coil, I DID get some interference, but I couldn't hear a squeal in the speaker of my radio. I put it away for now, I do have another FET I could f^Htry, but.. I don't want to damage it. I was thinking about removing the pot entirely and using a rotating "inner coil" serve in it's place: +v ------> (tickler coil) ---> [D|G|S] ---> audio out (Basically using both sides of the FET) Hooking the tank circuit up to the gate, just as before but eliminate the parts for controlling the tickler, sort of like this: <()> with < > being the tank coil and the () being a coil inside the <>'s in such a way you could turn it, controlling the tickler by changing it's angle. I've seen old regen radios that appear to do something like this, but constructing a coil that can be turned (w/out changing the tank and input coil's value) look tricky. A plastic ink pen could be the shaft for turning it, but keeping it in the center w/out wobbling.. As the parts MUST come from garbage, precise values are hard to get. To remove them is a good thing. :-) Not today though.... Jamie -- http://www.geniegate.com Custom web programming guhzo_42@lnubb.pbz (rot13) User Management Solutions Article: 98080 of rec.radio.amateur.homebrew Message-ID: <44BB2933.D6C61A01@earthlink.net> From: "Michael A. Terrell" Subject: Re: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 References: Date: Mon, 17 Jul 2006 06:08:16 GMT "kb9rqz@hotmail.com" wrote: > > why should I I just did not care for the action of another in trying to > jam a post that yea is spam is at least ontopic instead all the posters > trying to make issues out of people sexlife > > his product can be totaltrash but total trashis better than a post > that consists entily of "you are faggot" as many post here do > > you don't like his product don't buy it I've thrown away better wire and connectors, but you can use whatever garbage you want to. -- 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: 98081 of rec.radio.amateur.homebrew From: "an old freind" Subject: Re: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 each. Date: 17 Jul 2006 05:30:27 -0700 Message-ID: <1153139427.894267.305350@s13g2000cwa.googlegroups.com> References: Michael A. Terrell wrote: > "kb9rqz@hotmail.com" wrote: > > > > why should I I just did not care for the action of another in trying to > > jam a post that yea is spam is at least ontopic instead all the posters > > trying to make issues out of people sexlife > > you don't like his product don't buy it > > > I've thrown away better wire and connectors, but you can use whatever > garbage you want to. grow up Article: 98082 of rec.radio.amateur.homebrew Date: Mon, 17 Jul 2006 21:41:23 +0800 From: Richard Hosking Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> <5amib2thgqnfmg6dsmtbcol3t0m0v418q9@4ax.com> <44BA46E2.8D9A447@earthlink.net> <8PS9IMRMOmuEFANF@ifwtech.co.uk> Message-ID: <44bb9383$0$23381$5a62ac22@per-qv1-newsreader-01.iinet.net.au> The tongue is good to test a 9V battery _ I can tell if they are good. Havent done it on 240V tho. Worst Ive got is 240V off a cartridge fuse Richard Ian White GM3SEK wrote: > Michael A. Terrell wrote: > >> Ian White GM3SEK wrote: >> >>> >>> (But I'm a fine one to talk: my bad habit is to sniff the soldering iron >>> to see if it's hot :-) >> >> >> >> At least you stopped using your tongue to test it! ;-) >> > No, you've got it all wrong - you use your tongue to test if the > soldering iron is COLD. > > Article: 98083 of rec.radio.amateur.homebrew Message-ID: <44BB97DE.10B7D27E@earthlink.net> From: "Michael A. Terrell" Subject: Re: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 References: Date: Mon, 17 Jul 2006 14:00:28 GMT an old freind wrote: > > grow up Grow up? Its you that appears to have never grown up. You seem to have almost no grasp of the English language, or the concept of not supporting spammers. -- 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: 98084 of rec.radio.amateur.homebrew From: "an old friend" Subject: Re: FS: PL-259 silver plated contact & body, Teflon insulation $1.67 each. Date: 17 Jul 2006 07:12:42 -0700 Message-ID: <1153145562.073368.220120@m73g2000cwd.googlegroups.com> References: Michael A. Terrell wrote: > an old freind wrote: > > > > grow up > > > Grow up? yes grow up > Its you that appears to have never grown up. You seem to > have almost no grasp of the English language, or the concept of not > supporting spammers. disagreing with you is not a lack of aturity nor is is a sign of any lack of language skills I frankly don't see it as as pam (and BTW I am sure the original poste thanks you for the attentionyou are helping his prodcut to) spam is preferable to sexual inuendo which has become the NGs sock in trade I would rather see an ad for something that might be usefull in the gruop than what what we see as far as I am concerned to be spam it is has to e non related to the NG that you disagree or have personal issues with the poster is your proble OTOH I welcome the thread and even your as a rcahnce to talk about somthing related to radio > > > -- > Service to my country? Been there, Done that, and I've got my DD214 to > prove it. as have I Article: 98085 of rec.radio.amateur.homebrew From: "Mike Andrews" Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes Date: Mon, 17 Jul 2006 17:40:10 +0000 (UTC) Message-ID: References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> <5amib2thgqnfmg6dsmtbcol3t0m0v418q9@4ax.com> <44BA46E2.8D9A447@earthlink.net> Michael A. Terrell wrote: > Ian White GM3SEK wrote: >> >> (But I'm a fine one to talk: my bad habit is to sniff the soldering iron >> to see if it's hot :-) > At least you stopped using your tongue to test it! ;-) You folks are in good company: one of my friends, down in VK-land, shook some excess solder off the iron tip -- and then decided to wear pants from then on. -- About a deceased operator: I'm still more than a bit surprised that he was able to operate the weapon in such a fashion that it would fire. This is grossly inconsistent with _my_ experience of his abilities. Article: 98086 of rec.radio.amateur.homebrew From: "Mike Andrews" Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes Date: Mon, 17 Jul 2006 17:46:41 +0000 (UTC) Message-ID: References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> <12bbfr36ah4def3@corp.supernews.com> <5amib2thgqnfmg6dsmtbcol3t0m0v418q9@4ax.com> <44BA46E2.8D9A447@earthlink.net> Michael A. Terrell wrote: > Ian White GM3SEK wrote: >> >> (But I'm a fine one to talk: my bad habit is to sniff the soldering iron >> to see if it's hot :-) > At least you stopped using your tongue to test it! ;-) You folks are in good company: one of my friends, down in VK-land, shook some excess solder off the iron tip -- and then decided that if he was going to solder things, he'd wear pants, thanks very much. -- About a deceased operator: I'm still more than a bit surprised that he was able to operate the weapon in such a fashion that it would fire. This is grossly inconsistent with _my_ experience of his abilities. Article: 98087 of rec.radio.amateur.homebrew Message-ID: <44BBD0F6.325DBA3E@earthlink.net> From: "Michael A. Terrell" Subject: Re: Mains Was: Low cost SMD Oven for making SMD samples and Prototypes References: <1152701692.603004.306280@35g2000cwc.googlegroups.com> Date: Mon, 17 Jul 2006 18:04:06 GMT Ian White GM3SEK wrote: > > Michael A. Terrell wrote: > >Ian White GM3SEK wrote: > >> > >> (But I'm a fine one to talk: my bad habit is to sniff the soldering iron > >> to see if it's hot :-) > > > > > > At least you stopped using your tongue to test it! ;-) > > > No, you've got it all wrong - you use your tongue to test if the > soldering iron is COLD. I was in someone else's shop one day and saw something falling off the edge of the bench in my peripheral vision, and caught a hot soldering iron. Luckily I had my tool box with me so I grabbed some pure silicone grease and smeared it over the burns. I lost a layer of dead skin a few days later, but it didn't dry out enough to crack and bleed, which would have taken a lot longer to heal. -- 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: 98088 of rec.radio.amateur.homebrew From: "Reg Edwards" Subject: Length & number of radials Date: Tue, 18 Jul 2006 18:11:11 +0100 Message-ID: If you are considering a new vertical antenna, instead of guesswork and copying somebody else's un-thought-out efforts, download program RADIAL_3 from website below. The program assists with choosing an economic length and number of shallow-buried ground radials. It takes a new look at how radials work by considering them to be lossy, single-wire transmission lines, open-circuit at the other end. RADIAL_3 is a self contained file, 55 kilibytes. Easy to use. No training needed. Download in a few seconds and run immediately. ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 98089 of rec.radio.amateur.homebrew From: "AndyS" Subject: Re: What is a wire antenna's impedance? -followup Date: 18 Jul 2006 14:09:38 -0700 Message-ID: <1153256978.081184.264550@p79g2000cwp.googlegroups.com> References: <7T9tg.15155$Wh7.1326@trnddc07> John - KD5YI wrote: > Additional response to OP jo9s8as at yahoo.com: > > Using an MFJ259B with a #14 AWG (.064 dia) copper wire 19.4 inchs long stuck > into the antenna connector, I measured the following... > Andy comments, John, your results would be more consistent, and more meaningful, if you had some sort of ground plane in your experiments. A wire, by itself, with nothing else, is like trying to light a lamp with only one prong plugged into the socket...... The radiating element, which you are measuring, has to have a counterpoise (ground) to establish the Efield against and an Hfield around. In your setup, the housing of the MFJ, and your hand, and probly other stuff, is the counterpoise, and the results are inconsistent. I suspect that if you took a measurement, and started to pee on the ground, the reading would change (grin).......Try it. But keep the power low :>)))) So, while your experiments may give you an idea of what the resonant frequency and impedance of a piece of wire is, unless you are able to take consistent, repeatable measurements, you can be sure that something is not being accounted for..... My suggestion is that you need a good counterpoise...... Maybe buy a sheet of corrugated tin from Home Depot, mount the connector in the middle, with the MFJ on one side and the antenna wire on the other.... You'll find, I am certain, that your readings will be more consistent..... This is not a bad ground plane for 2 meters --- I have used one with good results...... It ain't magic, but there isn't any such thing as a unipole radiator.... Good luck, Andy W4OAH Article: 98090 of rec.radio.amateur.homebrew From: "Joel Kolstad" Subject: Re: What is a wire antenna's impedance? -followup Date: Tue, 18 Jul 2006 14:47:10 -0700 Message-ID: <12bqlmvsdbhisb2@corp.supernews.com> References: <7T9tg.15155$Wh7.1326@trnddc07> <1153256978.081184.264550@p79g2000cwp.googlegroups.com> "AndyS" wrote in message news:1153256978.081184.264550@p79g2000cwp.googlegroups.com... > The radiating element, which you are measuring, has to have a > counterpoise (ground) to establish the Efield against and an Hfield > around. I believe that -- at least from a mathematical perspective -- "infinity" is a perfectly good counterpoise. (Just as isolated conductors have capacitance to infinity and inductors have "partial inductance" whereby a return path at infinity is assumed.) As a practical matter, of course the user's hands and other objects in the environment will affect the measurement, but suggesting that "one must always have a well-defined counterpoise" would tend to discourage one from studying antennas that are less sensitive to counterpoises than those that are, and this endeavor is quite valuable for the design of miniature antennas. After all, there are millions of commercial devices in operation every day for which the counterpoise is ill-defined. Article: 98091 of rec.radio.amateur.homebrew From: Timothy@tholtom.freeserve.co.uk Subject: Newbie Question: PC Based Oscilloscopes Date: 18 Jul 2006 15:14:05 -0700 Message-ID: <1153260845.004678.264980@p79g2000cwp.googlegroups.com> I haven't touched RF test and measurement equipment for about 20 years. Back then I used a standard 50MHz dual trace scope. I want to get back into homebrewing, and was wondering whether anyone could advise me on buying PC based 'scopes. Do they have the same "look and feel" as a dedicated 'scope? There appear to be many such PC based scopes (e.g. Vellman), I was wondering what homebrewers would advise, given the "average" budget (not 10,000 Dollars + !!). Something with a pretty good Spectrum Analyser built in? Or would I be better off going to Ebay and buying an old dual trace scope for 100 Euros or so? Advice anyone? Article: 98092 of rec.radio.amateur.homebrew From: "AndyS" Subject: Re: What is a wire antenna's impedance? -followup Date: 18 Jul 2006 15:41:39 -0700 Message-ID: <1153262499.873796.22260@h48g2000cwc.googlegroups.com> References: <7T9tg.15155$Wh7.1326@trnddc07> Joel Kolstad wrote: > "AndyS" wrote in message > news:1153256978.081184.264550@p79g2000cwp.googlegroups.com... > > The radiating element, which you are measuring, has to have a > > counterpoise (ground) to establish the Efield against and an Hfield > > around. > > I believe that -- at least from a mathematical perspective -- "infinity" is a > perfectly good counterpoise. (Just as isolated conductors have capacitance to > infinity and inductors have "partial inductance" whereby a return path at > infinity is assumed.) > > As a practical matter, of course the user's hands and other objects in the > environment will affect the measurement, but suggesting that "one must always > have a well-defined counterpoise" would tend to discourage one from studying > antennas that are less sensitive to counterpoises than those that are, and > this endeavor is quite valuable for the design of miniature antennas. After > all, there are millions of commercial devices in operation every day for which > the counterpoise is ill-defined. Andy comments: Yes... well... maybe.. In order to propagate, the Poynting vector has to have an Efield and an H field. The E field is between the "wire" and it's counterpoise....specified in V/M .... that is the voltage between the two divided by the distance between them...... As an aside, the orientation of the Efield is the polarization of the antenna --- vertical, circular, horizontal, elliptical, etc.... Now, if the counterpoise was at infinity, the Efield must always be zero, since any voltage divided by infinity ( to give V/M) will be zero. Hence there can be no propagation...... Like connecting up to one terminal of a battery.. All antennae, even the very inefficient ones used in "commercial devices", have a hot side and a ground. If the ground is well defined, as in a patch antenna, the field and radiation characteristics are well defined. If the counterpoise is simply a ground track on the PC board, it is fairly well defined, but the radiation is, well, squirrelly. Fortunately, a matching circuit assures that power will be radiated, even if the field is not pretty. Loop antenna, which do not work against a ground plane, use one of the two feed points as a counterpoise. Such antennas are easier to visualize using H fields, tho, as before, one MUST have and E and an H field for it to actually work.... The Efields of a loop exist between sections of the loop as a function of the current flow thru the loop, and don't give much of an intuitive feeling...... but I digress... If you know of an antenna that has no counterpoise for the "hot" side to work against, please post some information about it...... However, in my experience, it would be like having a magnet with a North pole and no South pole ---- ain't no such thing..... Yet, I'd be glad to learn if you would care to teach..... Andy W4OAH PS And I would be very interested if Roy LeWallen would step in here with an opinion. He has done more antenna stuff than I have, and may be able to explain it better..... I know he hangs around this group since I have seen his posts . :>)))))) Article: 98093 of rec.radio.amateur.homebrew From: "AndyS" Subject: Re: Newbie Question: PC Based Oscilloscopes Date: 18 Jul 2006 15:53:23 -0700 Message-ID: <1153263203.500013.191710@m73g2000cwd.googlegroups.com> References: <1153260845.004678.264980@p79g2000cwp.googlegroups.com> Timothy@tholtom.freeserve.co.uk wrote: > I haven't touched RF test and measurement equipment for about 20 years. > Back then I used a standard 50MHz dual trace scope. I want to get > back into homebrewing, and was wondering whether anyone could advise me > on buying PC based 'scopes. Do they have the same "look and feel" as a > dedicated 'scope? > > There appear to be many such PC based scopes (e.g. Vellman), I was > wondering what homebrewers would advise, given the "average" budget > (not 10,000 Dollars + !!). Something with a pretty good Spectrum > Analyser built in? > > Or would I be better off going to Ebay and buying an old dual trace > scope for 100 Euros or so? > > Advice anyone? Andy writes: I've used a couple of the systems that plug into the PC and use software loaded into it. It is mainly an A/D converter with several channels, and the software gives the user the versatility to establish timing, etc... I MUCH MUCH MUCH prefer the old fashioned analog scopes, tho, since I can fiddle with it and don't have to worry about aliasing, sample rates, etc. I suppose the latter software programs have all the user friendly stuff built in, but, personaly, if I didn't write the program myself, I don't know where I would get into trouble applying it. I don't like to used "canned" "one program does all" stuff....... (unless I wrote it :>))) ). One really cheap system I used was, I think , BSOFT. I don't know if they are stillin business, but they sold a board that plugged into a PC (desk size) and only cost 50 - 100 bucks. Worked up to several Mhz. But that was 15 years ago -- everything is much faster now -- but you have to pay for it...... As I think about it, a big advantage for a PC scope is that the measurements are on a file somewhere, and if you have programming ability, you can write an FFT, or a graph program, or, well, hell, almost anything you can think of ---- providing you can access the data file.... That could be a lot of fun......... Good luck. But 50 mhz scopes are faily cheap now...... Andy in Eureka, Texas