I just noticed that on 80 and 17m the side tone in my K2 has a low frequency modulation superimposed over the normal frequency. When I discovered this I was trying to call a Panama station on 80m. I cranked the power up to 100w and started my call. The rig sounded like it was going nuts. It even locked into a repeating string of dits or das. I do not remember which. I turned the rig off to get it to stop. I suspect the repeating transmission is unrelated to the side tone problem because I found that my computer keying cable was part way out of the jack. It must have been bad timing that it came out just as I was calling.
The amplitude of the modulation on the side tone increases with power output, and is only noticeable at ~60 to 100 w. On 80m if I key down for several seconds the modulation decreases. It sounds like a capacitor charging. On 17m, the sound is much louder and does not decrease with time. The output signal sounds fine in another receiver. I tested using a dummy load. I also turned off my power supply and computer monitor, and used a battery to power the K2. Neither helped. I built the KPA100 this last spring, and have not noticed this before. However, I have been running mostly QRP so I do not know when this problem showed up. KPA100 is located in an EC2 with the KAT2. The connecting cable is 32 inches long. What should I look for to fix this? Jeff Burns AD9T _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
