Okay, I agree. I think as long as one can get a signal into the RF deck, it can be used to align the coils and trimmers as necessary.
I'm going to make a matching network and wondered if there was any really good reason to use 68 and 100 ohm resistors or 95 and 75 ohm resistors. Probably doesn't matter... Thanks, Barry - N4BUQ On Mon, Nov 4, 2024 at 12:52 AM Larry Haney <[email protected]> wrote: > > Hi Barry, Yes, the DA-121 is what's recommended for the 390A when doing > alignment, but it does not make any difference if you use the adapter or not > for that, but it should be used for sensitivity and SNR measurements. At > least, that's been my experience. > > I believe that the balanced antenna coils are a little different on the 390, > but the DA-121 should be close enough to work correctly for it. But, there > again, I doubt that an adapter is necessary for alignment on the 390, either. > It should be used for sensitivity and SNR measurements though. > > Regards, Larry > > > On Sun, Nov 3, 2024 at 6:04 PM Barry Scott <[email protected]> wrote: >> >> In the last few weeks, there were several posts regarding using the >> DA-121 to determine sensitivity for, presumably, an R-390A/URR. The >> DA-121 uses a 68-ohm in parallel and a 100-ohm in series with the >> signal generator's output. Is this the recommended adapter also to be >> used for the RF alignment of the R-390A/URR when using the balanced >> input? >> >> I ask because the R-390/URR manuals say to use a 75-ohm parallel >> resistor with a 95-ohm series resistor when performing the RF >> alignment. I realize there's not enough difference between those two >> networks to matter that much but I am curious as to why the two values >> are different between the models. Are the RF transformers slightly >> different between them? >> >> Just curious. >> >> Thanks, >> Barry - N4BUQ >> ______________________________________________________________ >> R-390 mailing list >> Home: http://mailman.qth.net/mailman/listinfo/r-390 >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
