The guests having departed - the Turkey finally disposed of - the booze consumed - thoughts turned to "Playing radio".
I have been getting reports on 80m that my SSB signal had some "edge" to it. At first I put it down to RF feedback, but that was not the problem. I used my FT1000MP to listen to the 2nd harmonic of the 80m signal. Having read recent mails I first monitored the 3.5MHz signal and found the "Buzz" that others had reported. I then tried the following frequencies on 80 and noticed that as I increased the power control on the K2 the power output would suddenly jump, then when the control was turned ACW the power would reduce smoothly and then suddenly drop. It was also observable on the FT1000MP S-meter, accompanied by a click. It was like a form of hysteresis. All other bands gave smooth power control. The results were as follows:- 3.8MHz Low point=20W High point=70W Hysteresis=50W 3.7MHz Low point=25W High point=70W Hysteresis=45W 3.6MHz Low point=35W High point=70W Hysteresis=35W 3.5MHz Low point=40W High point=70W Hysteresis=30W Very unsatisfactory... I substituted a 1k resistor for RFC3, and all the 80m problems went away. Smooth power control on all bands and a better SSB signal on 80m. Many thanks to those who found/cured this problem that first showed itself on CW, I would certainly have spent a lot of time tracking this one down ! I would suggest that owners of K2/100's check to see that their rig does not exhibit these symptoms as it can make quite a big difference to transmitted signal quality. I, like a previous correspondent think that Elecraft should make some comment on this design problem, and it's solution. 73 Stewart G3RXQ _______________________________________________ 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
