high-power tuner
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Vic,
Be aware that loss in the tuner can reduce the signal pickup - I would not be so quick to pass judgement that the Matchbox is less efficient than the T-network tuner - I know the link coupled tuner (properly used) is more efficient. You may want to double check your test conditions and instrumentation. 73, Don W3FPR. On 3/10/2012 4:38 PM, Vic K2VCO wrote: > I just did the following experiment: I coupled a grid-dip oscillator to my feed line far > from the tuners and switching relays. I put it a few inches from the feedline equidistant > from the conductors. I found that the T network plus DXE balun reduced the signal pickup > by about 15 dB over the Matchbox! > > That means that both radiation and noise pickup on the feedline are much less with the T > than with the Matchbox. At the same time I verified that there was no detectable > difference between the strength of received signals coming from the antenna. > > This is amazing! It means that the T network and balun is significantly better than the > Matchbox in this important respect. So much for mythology. > > On 3/10/2012 1:11 PM, Vic K2VCO wrote: >> I've recently been experimenting with tuners. I have a "275 watt" Johnson Matchbox >> (which is actually good for more than a kW on CW in most cases) and a huge T network >> that I just built with a massive edge-wound rotary inductor and capacitors with air gaps >> of about 3/8" (near 10mm). The T network has a DX Engineering "5 kW" rated 1:1 balun on >> the output. >> >> The antenna is an 88-foot dipole fed with 500 ohm open-wire line and some 450-ohm ladder >> line. >> >> I can switch between these tuners instantly. On 40 meter received signals I can detect >> absolutely no difference in signal strength. The T network is adjusted for the least >> possible inductance that gives a 1:1 SWR, and the output capacitor is at maximum (300 pf >> air plus 300 pf ceramic padder).. >> >> There is also no difference in noise level. If one of the tuners provided better >> balance, one would expect that there would be less noise pickup on the feedline. But I >> don't see this. >> >> One anomalous result: there is a weak unstable carrier that I can hear on the Matchbox >> but not on the T network. I have verified that this is not a birdie, but an actual >> signal. It could be attributed to feedline pickup -- but wouldn't you expect the >> matchbox to be better in this regard? I'm investigating further. >> >> -- >> Vic, K2VCO >> Fresno CA >> http://www.qsl.net/k2vco/ > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by K7TV
Ron, Rick, Erik: There are many reasons why temperature measurements are a
poor way of evaluating a tuner. There is a method of power measure based on temperature rise. It's called a bolometer. It only works well if the mass involved is small. Wiki bolometers if you want the details. I think there is an even more important reason not to use this approach. Let's consider the case where the transmitter has a very strong second harmonic say -10db. If the tuner is doing its job, tuning, not just matching, the 2nd harmonic will be tuned or filtered out. 10% of the energy will be lost. What becomes of that energy? In an ideal world that energy would be reflected into a dummy load, like when you use a circulator. Since most tuners don't have circulators, part of the energy will be dissipated in the tuner and part will be reflected back to the transmitter. That energy that is dissipated in the tuner is a measure of how well, not how poorly, the tuner is working. BTW in this case measuring SWR at the transmitter will also suggest the tuner is not doing its job well when it is. Now we know good rigs don't have strong harmonics but I think I have illustrated why measuring heat is not a good measure of performance. 73, Fred, AE6QL -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Erik Basilier Sent: Saturday, March 10, 2012 12:31 PM To: 'Ron D'Eau Claire'; 'Rick Stealey'; [hidden email] Subject: Re: [Elecraft] high-power tuner As has been clearly demonstrated in this thread, there are multiple methods of measurement. The one that gets my vote for elegance is the one with two tuners back-to-back. With respect to the method that measures temperature rise, taking into account the mass of the tuner, one also needs to take into account the specific heat capacity of the tuner. One kilo of material x doesn't heat up at the same rate as one kilo of material y when the same heating power is applied. The tuner will of course be a mix of materials, so one would have to measure the rate at which the tuner heats up when heat is applied through a know heating source rather than TX power. If it is done that way, one needs to know neither the mass nor the specific heat capacity, since what one is measuring is essentially the mass times the specific heat capacity. 73, Erik K7TV -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Ron D'Eau Claire Sent: Saturday, March 10, 2012 11:47 AM To: 'Rick Stealey'; [hidden email] Subject: Re: [Elecraft] high-power tuner I was investigating tuner losses a few years ago and ran into many of these same questions. A physicist buddy pointed out to me that the normal approach to measure loss in something like a tuner is to put it in a well-insulated chamber and measure the rise in temperature over time while transmitting. From there on can calculate the energy required to cause the temperature rise which can be used to calculate the number of watts of RF that never make it through the box. 73, Ron AC7AC -----Original Message----- There seems to have been no answer as to how to accurately measure the loss in a tuner. Here is a solution but requires two tuners or at least one calibrated one that could be used to measure others. Take first tuner and tune it into the mismatch, say 600 ohms. Use an antenna analyzer. Then remove the load, and connect another tuner to the output of the first (back- to-back - antenna port on first to antenna port on second tuner.) Then put a 50 ohm load on the second tuner where the transceiver would be connected, and tune the second tuner to a match. It will have the same settings as the first tuner, complete symmetry. Then measure the power in the 50 ohm load to get the loss. Since both tuners are matching the same load, and the system is symmetrical the loss contribution by each tuner is half. Repeat for other types of loads, and now you have a calibrated tuner to use with any tuner you want to test. Rick K2XT ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Don Wilhelm-4
This is why I checked that real signals received through the antenna were not attenuated
to a detectable degree. I could not tell the difference between the tuners with weak signals from distant stations. Reasons that the T network may be as efficient as the Matchbox for this test: 1) In this case the T output capacitor is maximum, which makes it an L network. 2) No switches in the path. 3) Very high-Q inductor in the T network. On 3/10/2012 4:06 PM, Don Wilhelm wrote: > Vic, > > Be aware that loss in the tuner can reduce the signal pickup - I would not be so quick to > pass judgement that the Matchbox is less efficient than the T-network tuner - I know the > link coupled tuner (properly used) is more efficient. > > You may want to double check your test conditions and instrumentation. > > 73, > Don W3FPR. > > On 3/10/2012 4:38 PM, Vic K2VCO wrote: >> I just did the following experiment: I coupled a grid-dip oscillator to my feed line far >> from the tuners and switching relays. I put it a few inches from the feedline equidistant >> from the conductors. I found that the T network plus DXE balun reduced the signal pickup >> by about 15 dB over the Matchbox! >> >> That means that both radiation and noise pickup on the feedline are much less with the T >> than with the Matchbox. At the same time I verified that there was no detectable >> difference between the strength of received signals coming from the antenna. >> >> This is amazing! It means that the T network and balun is significantly better than the >> Matchbox in this important respect. So much for mythology. >> >> On 3/10/2012 1:11 PM, Vic K2VCO wrote: >>> I've recently been experimenting with tuners. I have a "275 watt" Johnson Matchbox >>> (which is actually good for more than a kW on CW in most cases) and a huge T network >>> that I just built with a massive edge-wound rotary inductor and capacitors with air gaps >>> of about 3/8" (near 10mm). The T network has a DX Engineering "5 kW" rated 1:1 balun on >>> the output. >>> >>> The antenna is an 88-foot dipole fed with 500 ohm open-wire line and some 450-ohm ladder >>> line. >>> >>> I can switch between these tuners instantly. On 40 meter received signals I can detect >>> absolutely no difference in signal strength. The T network is adjusted for the least >>> possible inductance that gives a 1:1 SWR, and the output capacitor is at maximum (300 pf >>> air plus 300 pf ceramic padder).. >>> >>> There is also no difference in noise level. If one of the tuners provided better >>> balance, one would expect that there would be less noise pickup on the feedline. But I >>> don't see this. >>> >>> One anomalous result: there is a weak unstable carrier that I can hear on the Matchbox >>> but not on the T network. I have verified that this is not a birdie, but an actual >>> signal. It could be attributed to feedline pickup -- but wouldn't you expect the >>> matchbox to be better in this regard? I'm investigating further. >>> >>> -- >>> Vic, K2VCO >>> Fresno CA >>> http://www.qsl.net/k2vco/ >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Fred Townsend
Bolometers work at pretty low (milliwatt) power levels and you would need to use an attenuator, which could add some error to the measurement. Hewlett Packard made the HP434A Calorimetric Power Meter, which could measure up to 10 watts by matching the temperature in a load with that caused by DC power (which can be accurately measured). I often used one in the early 1960s (this was at work--they were a bit pricey for ham use).
Bob, N7XY On Mar 10, 2012, at 4:56 PM, Fred Townsend wrote: > Ron, Rick, Erik: There are many reasons why temperature measurements are a > poor way of evaluating a tuner. There is a method of power measure based on > temperature rise. It's called a bolometer. It only works well if the mass > involved is small. Wiki bolometers if you want the details. > > I think there is an even more important reason not to use this approach. > Let's consider the case where the transmitter has a very strong second > harmonic say -10db. If the tuner is doing its job, tuning, not just > matching, the 2nd harmonic will be tuned or filtered out. 10% of the energy > will be lost. What becomes of that energy? In an ideal world that energy > would be reflected into a dummy load, like when you use a circulator. Since > most tuners don't have circulators, part of the energy will be dissipated in > the tuner and part will be reflected back to the transmitter. That energy > that is dissipated in the tuner is a measure of how well, not how poorly, > the tuner is working. BTW in this case measuring SWR at the transmitter will > also suggest the tuner is not doing its job well when it is. > > Now we know good rigs don't have strong harmonics but I think I have > illustrated why measuring heat is not a good measure of performance. > > 73, Fred, AE6QL > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Erik Basilier > Sent: Saturday, March 10, 2012 12:31 PM > To: 'Ron D'Eau Claire'; 'Rick Stealey'; [hidden email] > Subject: Re: [Elecraft] high-power tuner > > As has been clearly demonstrated in this thread, there are multiple methods > of measurement. The one that gets my vote for elegance is the one with two > tuners back-to-back. With respect to the method that measures temperature > rise, taking into account the mass of the tuner, one also needs to take into > account the specific heat capacity of the tuner. One kilo of material x > doesn't heat up at the same rate as one kilo of material y when the same > heating power is applied. The tuner will of course be a mix of materials, so > one would have to measure the rate at which the tuner heats up when heat is > applied through a know heating source rather than TX power. If it is done > that way, one needs to know neither the mass nor the specific heat capacity, > since what one is measuring is essentially the mass times the specific heat > capacity. > > 73, Erik K7TV > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Ron D'Eau Claire > Sent: Saturday, March 10, 2012 11:47 AM > To: 'Rick Stealey'; [hidden email] > Subject: Re: [Elecraft] high-power tuner > > I was investigating tuner losses a few years ago and ran into many of these > same questions. > > A physicist buddy pointed out to me that the normal approach to measure loss > in something like a tuner is to put it in a well-insulated chamber and > measure the rise in temperature over time while transmitting. From there on > can calculate the energy required to cause the temperature rise which can be > used to calculate the number of watts of RF that never make it through the > box. > > 73, Ron AC7AC > > -----Original Message----- > > There seems to have been no answer as to how to accurately measure the loss > in a tuner. > Here is a solution but requires two tuners or at least one calibrated one > that could be used to measure others. > Take first tuner and tune it into the mismatch, say 600 ohms. Use an > antenna analyzer. > Then remove the load, and connect another tuner to the output of the first > (back- to-back - antenna port on first to antenna port on second tuner.) > Then put a 50 ohm load on the second tuner where the transceiver would be > connected, and tune the second tuner to a match. It will have the same > settings as the first tuner, complete symmetry. > Then measure the power in the 50 ohm load to get the loss. > > Since both tuners are matching the same load, and the system is symmetrical > the loss contribution by each tuner is half. Repeat for other types of > loads, and now you have a calibrated tuner to use with any tuner you want to > test. > > Rick K2XT > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html _____ N7XY DX Cluster Node - telnet to n7xy.net, port 7300 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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So, the Calorimetric HP meter uses the same principle as my suggested
measurement, with the only difference being that HP performs the reference measurement simultaneously with the target measurement rather than sequentially. Erik K7TV >Hewlett Packard made the HP434A Calorimetric Power Meter, which could measure up to 10 watts by matching the temperature in a >load with that caused by DC power (which can be accurately measured). I often used one in the early 1960s (this was at work-->they were a bit pricey for ham use). > >Bob, N7XY ....... > The tuner > will of course be a mix of materials, so one would have to measure the > rate at which the tuner heats up when heat is applied through a know > heating source rather than TX power. If it is done that way, one needs > to know neither the mass nor the specific heat capacity, since what > one is measuring is essentially the mass times the specific heat capacity. > > 73, Erik K7TV > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Fred Townsend
OK folks, I am really truly sorry I started this
tuner-efficiency-by-measuring-its-heat thread. I apologize. It was sort of an e-nerd joke and I really miscalculated the laugh-factor in it, it seems there was none, an unfortunate failing for me ... but too common. Boltzmann's Constant is in my HP48GX calculator, not that I actually know or care what to do with it at this point in my life. It would be hugely difficult to get any sort of accuracy in a measurement of the heat lost in a tuner to find its efficiency, I never meant it to be real or even close to reality. Again, I'm sorry to have been joking around on a serious list. Won't do it again. Please, everyone, use what works, have fun, enjoy the hobby with the great E-gear. My KPA500 is heating the room far more than my MFJ989C. If you can make QSO's, it works. 73, Fred K6DGW - Northern California Contest Club - CU in the 2012 Cal QSO Party 6-7 Oct 2012 - www.cqp.org On 3/10/2012 4:56 PM, Fred Townsend wrote: > Ron, Rick, Erik: There are many reasons why temperature measurements are a > poor way of evaluating a tuner. There is a method of power measure based on > temperature rise. It's called a bolometer. It only works well if the mass > involved is small. Wiki bolometers if you want the details. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Fred,
I would not apologize. I have enjoyed the thread which is about dead anyway. 73, Bill K9YEQ -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Fred Jensen Sent: Saturday, March 10, 2012 8:17 PM To: [hidden email] Subject: Re: [Elecraft] high-power tuner OK folks, I am really truly sorry I started this tuner-efficiency-by-measuring-its-heat thread. I apologize. It was sort of an e-nerd joke and I really miscalculated the laugh-factor in it, it seems there was none, an unfortunate failing for me ... but too common. Boltzmann's Constant is in my HP48GX calculator, not that I actually know or care what to do with it at this point in my life. It would be hugely difficult to get any sort of accuracy in a measurement of the heat lost in a tuner to find its efficiency, I never meant it to be real or even close to reality. Again, I'm sorry to have been joking around on a serious list. Won't do it again. Please, everyone, use what works, have fun, enjoy the hobby with the great E-gear. My KPA500 is heating the room far more than my MFJ989C. If you can make QSO's, it works. 73, Fred K6DGW - Northern California Contest Club - CU in the 2012 Cal QSO Party 6-7 Oct 2012 - www.cqp.org On 3/10/2012 4:56 PM, Fred Townsend wrote: > Ron, Rick, Erik: There are many reasons why temperature measurements > are a poor way of evaluating a tuner. There is a method of power > measure based on temperature rise. It's called a bolometer. It only > works well if the mass involved is small. Wiki bolometers if you want the details. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by k6dgw
As one Fred to another it was funny in the heat of the battle so to speak.
It fooled me and perhaps the case hardened too. Well done. 73 Fred, AE6QL -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Fred Jensen Sent: Saturday, March 10, 2012 6:17 PM To: [hidden email] Subject: Re: [Elecraft] high-power tuner OK folks, I am really truly sorry I started this tuner-efficiency-by-measuring-its-heat thread. I apologize. It was sort of an e-nerd joke and I really miscalculated the laugh-factor in it, it seems there was none, an unfortunate failing for me ... but too common. Boltzmann's Constant is in my HP48GX calculator, not that I actually know or care what to do with it at this point in my life. It would be hugely difficult to get any sort of accuracy in a measurement of the heat lost in a tuner to find its efficiency, I never meant it to be real or even close to reality. Again, I'm sorry to have been joking around on a serious list. Won't do it again. Please, everyone, use what works, have fun, enjoy the hobby with the great E-gear. My KPA500 is heating the room far more than my MFJ989C. If you can make QSO's, it works. 73, Fred K6DGW - Northern California Contest Club - CU in the 2012 Cal QSO Party 6-7 Oct 2012 - www.cqp.org On 3/10/2012 4:56 PM, Fred Townsend wrote: > Ron, Rick, Erik: There are many reasons why temperature measurements > are a poor way of evaluating a tuner. There is a method of power > measure based on temperature rise. It's called a bolometer. It only > works well if the mass involved is small. Wiki bolometers if you want the details. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Very interesting discussions about tuners/loss I didn't understand most of what was discussed anyway, hihi.
I have a little tuner history if anyone is interested. In a letter from Don Wallace W6AM, years ago, he told me he swore by the Johnson Viking Kilowatt tuner. He had one connected between each of his Collins 75A4 receivers and his rhombics. Not for matching, he had the rhombics dialed in very well, he said the big KW Johnson Matchbox was a good preselector, said he could peak up a weak signal in the noise enough to get improved copy. He said only the big Johnson KW tuner with the big coils would work as a preselector, the smaller Johnson Matchbox didn't work as a preselector. With our radios today I doubt if the big Johnson would help any. Bob K6UJ On Mar 10, 2012, at 8:50 PM, Fred Townsend wrote: > As one Fred to another it was funny in the heat of the battle so to speak. > It fooled me and perhaps the case hardened too. Well done. > 73 > Fred, AE6QL > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Fred Jensen > Sent: Saturday, March 10, 2012 6:17 PM > To: [hidden email] > Subject: Re: [Elecraft] high-power tuner > > OK folks, I am really truly sorry I started this > tuner-efficiency-by-measuring-its-heat thread. I apologize. It was sort of > an e-nerd joke and I really miscalculated the laugh-factor in it, it seems > there was none, an unfortunate failing for me ... but too common. > Boltzmann's Constant is in my HP48GX calculator, not that I actually know or > care what to do with it at this point in my life. > > It would be hugely difficult to get any sort of accuracy in a measurement of > the heat lost in a tuner to find its efficiency, I never meant it to be real > or even close to reality. > > Again, I'm sorry to have been joking around on a serious list. Won't do it > again. Please, everyone, use what works, have fun, enjoy the hobby with the > great E-gear. My KPA500 is heating the room far more than my MFJ989C. If > you can make QSO's, it works. > > 73, > > Fred K6DGW > - Northern California Contest Club > - CU in the 2012 Cal QSO Party 6-7 Oct 2012 > - www.cqp.org > > On 3/10/2012 4:56 PM, Fred Townsend wrote: >> Ron, Rick, Erik: There are many reasons why temperature measurements >> are a poor way of evaluating a tuner. There is a method of power >> measure based on temperature rise. It's called a bolometer. It only >> works well if the mass involved is small. Wiki bolometers if you want the > details. > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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