Hi Ron, Hi had a similar problem some months ago. Symptoms:
Suddenly loss of sensitivity ~ -20 to -40dB or more... Transmission was always ok. Measurement with miniVNA always correct (at ~0dBm power). Moving some connections remove sometimes the loss of sensitivity. (but all soldered or crimped connections were tested as 100% ok, no "cold" solder joint, or broken wire, etc) After searching a lot of time, i suspected "old" silvered connectors, plugs, etc Changing all connectors with non silvered ones, all is now perfect! My explanation, accepted by other OM, is the following: My "old" idea, (ham since 1970) was that silver oxide was conducting, may be true, but over an (undefined for the moment...) level. In RX mode, in the uV range, i suppose that the potential is insufficient to break the ultra thin sliver oxide layer. With 0dBm or more "level", the oxide layer should be broken and all is ok. If i'm correct , some mechanicals relays are not specified under some voltage levels and to commutate very low voltages, some "special" kind of metal contacts must be used. Since this "incident" ALL silvered plated connectors, plug, etc are banned from the shack ! I never had problem since i've taken this decision. My best 73, Rudi, HB9ARI Ron W3ZV wrote: > Started to play in the CQWWSSB. K3 started to exhibit intermittent loss > of gain after a transmission. Sometimes, stomping on the foot switch > brings it back up. Sometimes it takes a short transmission. No real > pattern to when it occurs. Receiver isn't totally deaf. Just way down. > Any ideas as to where the problem might be? I'm guessing its time for > the radio to take a trip home to the left coast. > > Ron W3ZV > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
