On Tue, 7 Sep 2010 10:01:26 -0700, George A. Thornton wrote: >I also tried silencing >the computer microphone, presuming that the microphone was picking up >audio from the spoken Tx and feeding it back somehow through one of the >sound cards.
Look at this again. This is a very common problem, usually caused by a piece of software switching the Windows Mixer in ways that it thinks you want. Remember that there are TWO Windows Mixers -- one for record, and the second for playback. There is another mechanism that sounds just like RF feedback but is actually modulation of the DC voltage as a result of IR drop when transmitting SSB. If the V- bus in the power supply is bonded to the chassis, that modulation, which sounds just like SSB on an AM RX, gets added to the TX audio. W8JI was the first to alert us to this problem, and I have done testing to duplicate it in my shack. This problem can also happen if you get power for accessories direct from the power supply and then connect them to the rig. 73, Jim K9YC ______________________________________________________________ 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
