I have heard this relay noise since I put together my K3 kit s/n 1484 in August 2008. I always use full QSK, and then it's easy to hear the clicks if the room is silent. I was little surprised in the beginning, as I had read that the T/R switching should be all electronic. I didn't think no more about that, as I have KPA100, KAT3 and KXV3 installed I thought that there was a small relay somewhere on the options modules.
Today I did some tests, and took the top cover off and tried to listen carefully after the clicks. I am sure that it comes from a relay located somewhere under the KPA100 module. Not from KAT3 or the LP filter relays. There is no change in clicks if I put the radio in TX TEST mode or have full RF output, so it is not RF or high current related. It very hard to hear if I close PTT or a key manually or tap XMIT, but it is still there. CW mode , SSB mode or KPA100 disabled, it is still there every time T/R is switching. After a quick look at the K3 LPA schematic, I can se a small relay K1, "3 dB attenuator". What is that relay doing ? Can that be a candidate for causing the noise? I have just done the same tests with an other K3 that was factory build. Both radios produces exactly the same relay noise. I am using the lastest software in the radios now, but it have been the same thing with older software. 73 Classe SM3GSK ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft 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
