Hi Jim, Just curious where you found that document. The ones I'm finding don't appear to address/explain that dummy antenna and they're not searchable.
Thanks, Barry - N4BUQ On Sun, Oct 13, 2024 at 2:53 AM Jim Whartenby via R-390 <r-390@mailman.qth.net> wrote: > > Bob > > The test method for the R-390 acceptance is Mil-R-13947B, the document I > found on the web is searchable so I found the applicable sections easily by > searching (Control F) with the term "dummy". > > The spec for the dummy antennas is TB SIG 319 aka Electronic Equipment > Maintenance Kit MK-288/URM, it contains the schematics for both the balanced > and unbalanced dummy antennas. The former simulates the 125 ohm balanced > dipole antenna and the latter simulates the 50 ohm unbalanced input which is > a whip antenna. > > The balanced dummy antenna does the conversion from a 50 ohm system to a 125 > ohm system. The 9 dBV loss means that the SG is 2.82 times the signal > applied to the balanced input of the receiver so would this mean that one has > more of a sensitivity range since the SG is several dBv above minimum RF > output of the SG? > > The resistive dummy antenna is good for all frequencies covered by the R-390. > I am still not sure about the balun. I don't have enough experience to pick > the best ferrite material. The impedance transformation is from 125 / 50 or > 2.5:1 I know that you said that two primary turns and five secondary turns > on the balun should do the trick but as I said, I don't have much experience > with baluns. Since there are six octaves between 500 kc and 32 mc, which > ferrite material, in your opinion, will have the best response? > > I think that the original confusion that started this thread is that the > above spec calls out a much higher SG input to the balanced input then most > believe is the normal R-390 receiver sensitivity. Granted, the spec does not > mention that there is a 9 dBv difference between what the SG indicates and > the actual input to the R-390 balanced input. But the spec doesn't have to > explain, it just says if you "do this" and you "get that", the receiver > passes the acceptance test. As is often said, Spec is Spec so you don't have > to read into it. > > Regards,Jim > > Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy > > On Saturday, October 12, 2024 at 06:13:24 PM CDT, Bob Camp > <kb...@n1k.org> wrote: > > Hi > A properly done balun should give you a significant improvement in the > measured sensitivity. > Ok since we’ve been around a bit on this … .what test method? > 1) Test the radio straight out of a typical signal generator with no “stuff” > between the radio and the generator > VS > 2) Test things the same way, but put in the balun. > If the balun is properly done *and* it’s hooked up right … 2 should be > noticeably better than 1. > One note: some of these “adapters” are resistor based rather than having a > balun in them. That’s not the same thing. > Keep in mind that this may not be the best thing to do overload wise, it only > is “best” if you are after sensitivity. > Bob > > > On Oct 12, 2024, at 2:43 PM, Ing. Giovanni Becattini > <giovanni.becatt...@icloud.com> wrote: > > Hi Jim,I am better and did the test you suggested me. The reduction is > exactly 2 dB on the R-390A meter, with or without the DA-124 on the > unbalanced antenna. > Regarding the balun theme, who sold me the 390 gave me also a little balun: > practically a twinax to bnc adapter with a fatter body. It is marked as > specific for the 390, but with it things go much worse: more noise and less > sensitivity. > > > Il giorno 12 ott 2024, alle ore 01:13, Jim Whartenby <old_ra...@aol.com> ha > scritto: > Jacque , Gianni and Bob Sorry for being a bit late in continuing the > discussion. Life gets in the way. > In my zeal to solve for the attenuation of the DA-121, I should not have > combined the SG impedance with the DA-121. That would be fine for DC circuit > analysis but not for a transmission line. My apologies. > I found this nifty calculator that will solve for the resistor values for > every type of resistive attenuator. See: > https://k7mem.com/Res_Attenuator.html > I entered the following values: Z1 = 50 ohms, Z2 = 125 ohms and an > attenuation of 9 dB. It spit out the exact values for the resistors used in > the DA-121. The series resistor on the SG side of the shunt resistor is less > then a 1/4 ohm so it has little effect so it was obviously omitted in the > DA-121. The 5% resistor values given are again exactly those used in the > DA-121. The calculator also solves for 1% resistor values. > 9 dB is the minimum attenuation that returns positive resistor values and > does the conversion from 50 ohms to 125 ohms. Any attenuation below 9 dB > returns a negative resistor value for R1, the series resistor on the SG side > of the shunt resistor. > As Bob mentioned in a separate email, a balun would be the modern solution if > the ferrite core is capable of operating over the whole range of the R-390. > My balun experience is limited so I do not know which ferrite material will > do the job.Regards,Jim > Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy > > On Tuesday, October 8, 2024 at 10:30:33 AM CDT, Jacques Fortin > <jacque...@videotron.ca> wrote: > > Hello Gianni, > PLEASE READ MY COMMENTS IMBEDDED IN YOUR TEXT BELOW. > I USE THE UPPERCASE TEXT BECAUSE EVERY OTHER FONT ATTRIBUTE IS CLEARED UP BY > THE FORUM SERVER. > > 73, Jacques, VE2JFE in Montreal > > Hi Friends, forgive the savage who tries to understand how the clock works :) > What you Bob say is exactly what I would like to understand, i.e., if the > incredibly high sensitivities I heard are real or fantasy. > Let's imagine that we are in a perfect word and neglect the frequency effect. > All the discussion started, from my side, to determine the attenuation factor > of the DA-121. So I try to better focus my questions: > > 1) if I have a siggen with 50 ohm output and an rx with 50 ohm input, is it > correct to say that the voltage at the receiver’s input is that pointed out > by the generator’s knob? > > EXACT: MOST GENERATORS INDICATES THE OUTPUT VOLTAGE WHEN THE EXTERNAL LOAD IS > EQUAL TO THE INTERNAL OUTPUT IMPEDANCE. > (MAXIMUM POWER TRANSFER CASE) WHICH MEANS 50 OHMS FOR MOST OF THE AMERICAN > STUFF BUT 75 OHMS FOR THE OLD BRITISH ONES. > SOME HAVE ALSO (LIKE MY OLD TRUSTY HP 8657A) A SETTING THAT INDICATES THE > "UNLOADED" OUTPUT VOLTAGE AS THE EMF (ELECTROMOTIVE FORCE) VALUE. > TO BE CLEAR, WITH A "NORMAL" RF GENERATOR SET TO DELIVER 10mV IN A 50 OHMS > LOAD, THE INTERNAL "EQUIVALENT" GENERATOR IS A 20mV SOURCE IN SERIES WITH A > 50 OHMS RESISTOR (THE THEVENIN EQUIVALENT OF THE SOURCE, IF YOU LIKE). > > 2) in this specific case, I have a black box, constituted by the DA-121 > (68/100 ohm) and the R-390. It seems that from the generator’s point of view > it is equivalent to a rx with 50 ohm input impedance. So, if I set the > generator for 10 mV output, I have 10 mVrms at the 68 ohm resistor. Right? > > NOT EXACTLY: IF THE OUTPUT OF THE DA-121 IS UNLOADED, 11.525 mV WILL APPEAR > ACROSS THE 68 OHMS RESISTOR AND THE THEVENIN EQUIVALENT OF THE DA-121 OUTPUT > WILL BE A 11.525 mV SOURCE IN SERIES WITH A 128.81 OHMS RESISTOR. > WITH THE DA-121 OUTPUT LOADED BY A 125 OHMS RESISTOR, THE VOLTAGE ACROSS IT > WILL BE 5.676 mV. > COMPARED TO THE GENERATOR "SET" VALUE OF 10mV, THIS IS 4.919 dB lower. > > 3) if above is right, the effective voltage at the receiver’s input (125 ohm) > is the voltage at the 68 ohm reduced by the divider made by 100+125 ohm. > Right? > > RIGHT, IN ALL CASES. > > If so, the loss factor of the DA-121 is 3 dB ( Vin x .56). > 20 log (.56) = - 5 dB, not 3 dB.... > > This can be practically tested, and the voltage at the 125 ohm resistor I am > using instead of the R-390 for simplicity is exactly 0.56 Vin (this is true > also for DC). > > PRETTY CLOSE TO THE THEORICAL VALUE, RIGHT. > > This above is what I can suppose by myself but I understand you are > explaining to me that it is wrong. > > But If you are right, the DA-121 should have a 9 dB loss factor, and this > seems to be completely denied from the practical experience. Again, forget > the frequency effect until this point. > > SAY 4.9dB LOSS. > BUT IF THE DA-121 68 OHMS RESISTOR IS REPLACED BY A 50 OHMS ONE, THE GLOBAL > ATTENUATION (REAL OUTPUT AT THE 125 OHMS LOAD VS THE SG SETTING) WILL BE 6 dB > LOWER (0.5) AND THE DA-121 OUTPUT IMPEDANCE WILL BE 125 OHMS ALSO (MAXIMUM > POWER TRANSFER CASE). > > Thanks for your patience :) > > Gianni > > > > > > Il giorno 8 ott 2024, alle ore 14:58, Bob Camp <kb...@n1k.org> ha scritto: > > > > Hi > > > > Another wrinkle in this: > > > > If your generator is set to 1 uV, that should mean you get 1 uv across a 50 > > ohm load on the generator. The impedance at that point is 25 ohms (50 ohms > > for the load in parallel with 50 ohms from the generator). > > > > If your receiver happens to be a high impedance input (as many are ….) you > > get 2 uV at the input to the radio and the impedance is 50 ohms. > > > > Maybe take out some random load resistor and you just doubled the > > sensitivity. > > > > Why would you do this? (though maybe not at HF …) > > > > When you go from 25 ohms to 50 ohms, the thermal noise from the resistor(s) > > goes up by 3 db. Your signal went up by 6 db. You are now 3 db further > > above the thermal noise floor. > > > > Not a big deal on the typical HF setup. It is a big deal as you go up in > > frequency. Yes this makes some other things you do up there “fun” …. Even > > at HF, folks racing to get that 0.001 uV sensitivity number (or some > > equally absurd number) probably are doing this as well. > > > > So: counting on this or that radio to supply a matched input …. maybe not a > > good idea without testing out the specific radio at the operating frequency. > > > > Bob > > > > > > > >> On Oct 8, 2024, at 3:31 AM, Ing. Giovanni Becattini via R-390 > >> <r-390@mailman.qth.net> wrote: > >> > >> Hi Jim, > >> > >> I am not sure I can follow you. As I told, I am not using the R-390A but > >> just a 125 ohms resistor as a terminator. > >> > >> So: > >> 68 // 225 = 52.21 (seen from the generator) > >> > >> The voltage on the rx is then the siggen’s output voltage divided by > >> 100+125, i.e. Vin x 0.556. In dB, 3 dB, that is what I wanted to know. > >> > >> I tested that also in DC, with the same results. Luckily for this time > >> practice and theory are completely in accord. > >> > >> Things could be different increasing the frequency, obviously, and using > >> the real R-390A, but in my case, @ 7.5 MHz, they are rather similar. > >> > >> Am I wrong? > >> > >>> Il giorno 7 ott 2024, alle ore 22:28, Jacques Fortin > >>> <jacque...@videotron.ca> ha scritto: > >>> > >>> Jim, I do not know if I can follow you correctly in your explanations > >>> below. > >>> How does this DA-121 adaptor is made ?? > >>> > >>> 73, Jacques, VE2JFE in Montreal > >>> > >>> -----Message d'origine----- > >>> De : r-390-boun...@mailman.qth.net <r-390-boun...@mailman.qth.net> > >>> De la part de Jim Whartenby via R-390 Envoyé : 7 octobre 2024 12:42 > >>> Cc : r-390@mailman.qth.net Objet : Re: [R-390] Official specs > >>> > >>> Well, mailman not only strips photos but also any changes in typeface so > >>> the larger type and bold letters are stripped as well. > >>> Logic: Method used to arrive at the wrong conclusion, with > >>> confidence. Murphy > >>> > >>> On Monday, October 7, 2024 at 10:53:50 AM CDT, Jim Whartenby via R-390 > >>> <r-390@mailman.qth.net> wrote: > >>> > >>> GianniComments in BOLD > >>> > >>> On Monday, October 7, 2024 at 02:43:53 AM CDT, Ing. Giovanni Becattini > >>> <giovanni.becatt...@icloud.com> wrote: > >>> > >>> Hi Jim and thanks for your patience, but I still don’t understand. > >>> The generator sees 50 // (100+125), 50 // 225 = 52.22 ohm No, this > >>> should be 40.9 ohms not 52.22 ohms! R in parallel = 1/ (1/50 + 1/ > >>> 225) so 1/ (1/50 + 1/225) = 40.9 ohms or if you prefer > >>> > >>> > >>> product over sum = (50 X 225) / (50 + 225) = 11,250 / 275 = 40.9 > >>> ohms > >>> > >>> > >>> The result of two resistors combined in parallel will always be a lower > >>> value then the lowest of the two combined resistors. > >>> Going a step further, 40.9 ohms in parallel with the Signal Generator > >>> impedance of 50 ohms results in an impedance of 22.5 ohms so the SG now > >>> sees about half of the expected impedance. You can think of the SG as > >>> being a current source feeding a 50 ohm resistor. If the current source > >>> now sees half the expected impedance, the voltage output of the SG will > >>> now be half of the set voltage. > >>> > >>> Now applying the voltage divider rule to the series 100 ohm and shunt 125 > >>> ohm resistors, the voltage across the 125 ohm resistor will be the SG > >>> voltage X (125 / 225) = SG voltage X 0.55 We already know that the > >>> signal generator output is half of what the SG attenuator says so 0.5 X > >>> 0.55 = 0.27 so the output of the DA-121 is now approximately one fourth > >>> of the SG dial setting. > >>> I checked with the VOM using a 125 ohm terminator instead of the R-390A > >>> and read 52.4 ohm. You must have a wiring error! The DA-121 should read > >>> approximately 40.9 ohms at the SG terminals when the DA-121 output is > >>> terminated with 125 ohms. This is what was calculated above. If you now > >>> put a 50 ohm resistor across the DA-121 input, the resistance of the > >>> input to the DA-121 should measure approximately 25 ohms. > >>> To be sure that I was not tricked by the cables, I made the same test at > >>> 100 kHz with 10 mV and that below is what I read, again using the 125 ohm > >>> terminator on the oscilloscope side. > >>> Probably I am doing something wrong, but what? > >>> Your experimental data should closely agree with the math, it does > >>> not. There is at least a simple wiring error or the BNC to TWINAX > >>> adapter is not wired properly. As I mentioned in the email below, > >>> one of the TWINAX pins should be directly connect to the BNC center > >>> conductor, the other TWINAX pin should be directly connect to the > >>> shell of the BNC connector. There should not be any measurable > >>> resistance, ideally a short circuit for both ohmmeter readings. Can > >>> you verify this? Thanks again Gianni Regards, Jim > >>> > >>> > >>> > >>> > >>> Il giorno 6 ott 2024, alle ore 17:05, Jim Whartenby <old_ra...@aol.com> > >>> ha scritto: > >>> Gianni > >>> > >>> > >>> There is something wrong with your measurements. They do not agree with > >>> the mathematical analysis. > >>> > >>> > >>> > >>> > >>> > >>> Reducing the resistances of the DA-121 with the input resistance of the > >>> R-390 to a single resistance results in the total resistance seen by the > >>> SG of 25 ohms. So the generator output should fall from 10 mV to 5 mV > >>> which you confirm although there is an error of some 14% ((5.7 mV - 5 mV) > >>> / 5 mV). But as you say, the resistors are not perfect. > >>> > >>> > >>> What is apparently the problem is that your adapter from BNC to TWINAX > >>> does not measure correctly. One TWINAX pin should connect to the BNC > >>> center pin and the other TWINAX pin should connect to ground. If this > >>> does not happen, the second voltage divider, the 100 ohm in series with > >>> the 125 ohm is not connected to ground. This error would give you the > >>> voltage that you measure. > >>> > >>> > >>> There is agreement between us that when the 68 ohm resistor is connected > >>> to the SG that the output will fall from 10 mV to about 5 mV. Putting > >>> the two remaining resistors into the circuit results in a series 100 ohm > >>> resistor and a parallel 125 ohm resistor. Applying voltage divider > >>> analysis to this we have (5 mV X 125 ohms) / 225 ohms) which equals 2.28 > >>> mV. 2.28 mV divided by 10 mV gives a ratio of 0.23 which is in agreement > >>> with the DA-121 reducing the SG output from 10 mV to 2.5 mV or 4:1. > >>> > >>> > >>> The above analysis agrees completely with figure 3, the analysis of a > >>> T-pad, which was done in the 1950s. It changes the SG impedance of 50 > >>> ohms to the receiver impedance of 72 ohms with a voltage loss of 4:1 > >>> which I again enclose in this email. > >>> > >>> > >>> Regards, > >>> > >>> Jim > >>> Logic: Method used to arrive at the wrong conclusion, with > >>> confidence. Murphy > >>> > >>> On Sunday, October 6, 2024 at 01:46:02 AM CDT, Ing. Giovanni Becattini > >>> <giovanni.becatt...@icloud.com> wrote: > >>> > >>> Hi Jim,Setting rge SG to 10 mV I have1) with no terminator > >>> oscilloscope side: 20 mV2) with 50-ohm terminator: 10 mV3) with > >>> DA-121 no terminator: 11.4 mV4) with DA-121 and 125 ohm terminator > >>> (which simulates the receiver): 5.7 mV > >>> > >>> exactly as I would expect. Now I am going to pickup another generator to > >>> see if it behaves like the 8640. In the afternoon I tell you the result > >>> of the test. > >>> YoursGianni > >>> > >>> Il giorno 6 ott 2024, alle ore 00:00, Jim Whartenby <old_ra...@aol.com> > >>> ha scritto: > >>> > >>> Giovanni > >>> > >>> If you measure twice the voltage with no load on the SG then the actual > >>> voltage when the SG is properly loaded with a 50 ohm termination, what > >>> does the meter read when you put a 25 ohm resistor on the SG output? It > >>> should now read a third of the unterminated SG voltage. > >>> > >>> > >>> > >>> > >>> Enclosed is page 51 of the Measurements catalog. Figure 3 shows a T pad > >>> to match 50 ohms to 72. The resistor values are chosen to reduce the SG > >>> output voltage by half at the input to the T pad and to 1/4 at the output > >>> of the T pad when the T pad is terminated with a 72 ohm resistor. > >>> > >>> > >>> > >>> > >>> The same is done with the DA-121 but the impedance transformation is now > >>> from 50 to 125 ohms. Can you measure the voltages at the output of the > >>> SG with an oscilloscope? It should be 2X of the SG meter reading with no > >>> load on the SG, 1X with a 50 ohm load and 1/4X of the SG meter at the > >>> output of the DA-121 when the DA-121 is terminated with a 125 ohm non > >>> inductive resistor in place of the R-390A. If you do not terminate the > >>> DA-121 with a 125 ohm load then what you report as 0.56 of the SG meter > >>> reading would be correct. > >>> > >>> Regards, > >>> > >>> Jim > >>> > >>> > >>> Logic: Method used to arrive at the wrong conclusion, with > >>> confidence. Murphy > >>> > >>> On Saturday, October 5, 2024 at 03:14:58 PM CDT, Ing. Giovanni Becattini > >>> <giovanni.becatt...@icloud.com> wrote: > >>> > >>> Thanks for replying, I am very intrigued by this theme. > >>> See below please and tell me your opinion. > >>> > >>> > >>> Il giorno 5 ott 2024, alle ore 20:33, Jim Whartenby via R-390 > >>> <r-390@mailman.qth.net> ha scritto: > >>> Giovanni > >>> > >>> I need some clarifications. > >>> > >>> 1) You said: "It attenuates the signal voltage of 0.56 V, i.e. 5 dB."So > >>> the Signal Generator (SG) meter indicates that the output voltage is 0.56 > >>> volts or are you are measuring 0.56 volts at the output of the DA-121/U > >>> when the SG meter reads 1 volt? If so, how are you measuring this > >>> voltage? Is it peak or peak to peak or RMS? The assumption here is that > >>> it is RMS. > >>> I wrote wrongly; I meant that the DA-121 is a voltage divider that, > >>> considered 125 ohm the input impedance of the receiver, multiplies the > >>> siggen voltage x 0.56. > >>> > >>> 2) The DA-121/U contains two resistors, a 68 ohm resistor in > >>> parallel with the signal generator output and a series 100 ohm > >>> resistor to the center pin of the BNC output connector. You are > >>> then adapting the BNC output connector of the DA-121/U to TWINAX and > >>> then connecting it to the balanced RF input connector on the back of > >>> the R-390A, correct? Yes > >>> > >>> 3) What are the two resistor values in the DA-121 when you measure with > >>> your DMM? How close are they to what is expected? I am guessing that > >>> these two resistors are carbon composition and are a bit off in value. > >>> It is interesting to note that carbon composition resistors will change > >>> value when soldered into a circuit. No, it is not the original, I built > >>> it with new components. > >>> > >>> 4) When you measure the BNC to TWINAX adapter, one of the TWINAX pins > >>> goes to the center pin of the BNC connector and the other TWINAX pin goes > >>> to ground? Yes Both read close to zero ohms? each other yes, but they > >>> are open to ground. > >>> > >>> 5) How old are the coax cables used in your measurements? In other > >>> words, how lossy are they? Coax ages so the cable losses will increase > >>> and it will have an affect on your measurements. The coax is 50 ohms? > >>> Yes, they are normal BNC/BNC, 1 meter long, with 50 ohm cable, bought new > >>> ready to be used. > >>> > >>> The way I see it, 50 ohms in parallel with 68 ohms = 29 ohms. 29 ohms in > >>> series with 100 ohms = 129 ohms which is approximately your impedance > >>> transformation needed from 50 to 125 ohms. Because of the 68 ohms is in > >>> parallel with the SG output, the voltage at this point should be half of > >>> what the SG meter indicates. I am not sure it is so. The siggen indicated > >>> voltage is in Vrms and it is true when you have a 50 ohm load. If you > >>> don’t have the 50 ohm load, the voltage is double. I am sure of this, I > >>> tested more times with different generators and oscilloscopes. > >>> > >>> > >>> The second voltage divider of 100 and 125 ohms is again reducing the SG > >>> output voltage by another half so the actual voltage applied to the > >>> receiver is 0.5 X 0.5 or 0.25 times the SG meter reading. In other > >>> words, actual voltage applied to the R-390A receiver is 1/4 of what the > >>> SG meter indicates or 12 dB down. No, I am sure of 0.56. In the doubt, I > >>> built a 125 ohm terminator and checked with the oscilloscope. Starting > >>> with 10 mVrms I read 5.7 mVrms because the resistors are not perfect. And > >>> thus reduces the voltage by 5 dB. Do you agree? > >>> > >>> So what this means to the original discussion is that the 6.5 microvolt > >>> limit in the R-390A specification is actually 1.6 microvolts that is > >>> applied to the R-390A balance RF input for a 10 dB S+N/N reading when all > >>> of the losses in the test setup are accounted for. So the spec has > >>> simplified the measurement and eliminated all of the above math. Again, > >>> spec is spec and those who wrote it knew what they were doing. > >>> > >>> This back of the envelope analysis does not agree with what you have > >>> measured. I am interested in what you find when you have a chance to > >>> take a closer look. > >>> > >>> Jim > >>> > >>> Logic: Method used to arrive at the wrong conclusion, with > >>> confidence. Murphy > >>> > >>> On Saturday, October 5, 2024 at 01:48:09 AM CDT, Ing. Giovanni Becattini > >>> <giovanni.becatt...@icloud.com> wrote: > >>> > >>> Hi Jim and thanks for your reply. I read the very interesting document > >>> you pointed out. I did not understand everything, but for my practical > >>> interest it confirms that the impedance matching is mandatory. > >>> I am using an HP8640B as a signal generator. Let’s suppose it is ideally > >>> calibrated. I use also the DA-121/U impedance adapter which shows 50 ohm > >>> to the siggen and 125 to the receiver. It is the fourth type of pad of > >>> figure 4 of the article. > >>> My practical question is how to take in account the DA-121? > >>> It attenuates the signal voltage of 0.56 V, i.e. 5 dB. So, > >>> - in volts: the voltage value for the 10 dB S/N I read on the generator’s > >>> scale should be multiplied by 0.56. > >>> - in dBm: the dBm value for the 10 dB S/N I read on the generator’s > >>> scale should be reduced by 5 dBm. > >>> > >>> Is this correct? > >>> Thanks > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> ______________________________________________________________ > >>> R-390 mailing list > >>> Home: http://mailman.qth.net/mailman/listinfo/r-390 > >>> Help: http://mailman.qth.net/mmfaq.htm > >>> Post: mailto:R-390@mailman.qth.net > >>> > >>> This list hosted by: http://www.qsl.net Please help support this > >>> email list: http://www.qsl.net/donate.html > >>> ______________________________________________________________ > >>> R-390 mailing list > >>> Home: http://mailman.qth.net/mailman/listinfo/r-390 > >>> Help: http://mailman.qth.net/mmfaq.htm > >>> Post: mailto:R-390@mailman.qth.net > >>> > >>> This list hosted by: http://www.qsl.net Please help support this > >>> email list: http://www.qsl.net/donate.html > >>> > >>> ______________________________________________________________ > >>> R-390 mailing list > >>> Home: http://mailman.qth.net/mailman/listinfo/r-390 > >>> Help: http://mailman.qth.net/mmfaq.htm > >>> Post: mailto:R-390@mailman.qth.net > >>> > >>> This list hosted by: http://www.qsl.net Please help support this > >>> email list: http://www.qsl.net/donate.html > >> > >> ______________________________________________________________ > >> R-390 mailing list > >> Home: http://mailman.qth.net/mailman/listinfo/r-390 > >> Help: http://mailman.qth.net/mmfaq.htm > >> Post: mailto:R-390@mailman.qth.net > >> > >> This list hosted by: http://www.qsl.net Please help support this > >> email list: http://www.qsl.net/donate.html > > > > > > > > > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:R-390@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:R-390@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
