After years of using the same* station configuration, for the last couple weeks I have a weird thing that I haven't been able to explain or isolate a cause for.
Using one of my headsets, the sidetone decreases in volume by at least about 10 dB during a transmission. Usually it happens quickly but sometimes gradually. After a short rest it usually resumes its normal volume. It happens regardless of monitor volume setting. The tone produced when you adjust the volume is not affected. RX audio is not affected. It's not 100% due to RFI because it happens even if I have transmit disabled. It happens regardless of whether I use the rear panel or front panel jack and regardless of CW/SSB/digital. It does seem to be more likely to happen when I'm transmitting, though, which is why I say "not 100%" RFI. Let's just say that the behavior seems to be aggravated by RF or the fluctuating DC voltage that comes with it. I've checked my bonding and connectors for tightness and everything seems OK. The offending headset is a Koss SB/49 that I've used for more than three years. It doesn't happen with any of my other headsets. One distinguishing factor is that this set has a high impedance, 280 ohms DC. The other sets are in the range of 40-120 ohms. 73, Carl WS7L * Well not QUITE the same. Last summer I did several of the K3S upgrades including the KIO3B. ______________________________________________________________ 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 Message delivered to [email protected]
