Fraser, G4BJM wrote: "Interesting Earl, the non exhaustive tests I've done indicate that it is not due to magnetic fields." ---------- When I first told Elecraft about this problem, they sent me the new shield for the KPA100, which didn't help. Then they sent a mod kit that had to do with reducing spurious RF, which didn't help.
Then I eliminated the KPA100 as being the culprit by removing it (and installing the original cover). Driving the amp (with only the 10 watts available) resulted in the same problem. Clean when barefoot (as is the KPA100). Then I manually keyed the amp (instead of using the KPA-100's key output) -- no change in problem. Then I brought my K2/100 over to a friend's QTH and tried it with his amp -- same problem. Separation from his amp was 6 feet. His amp is an Alpha 99, mine is an Alpha 76CA (both have hypersil HV transformers). Then, at my home QTH, I set up the K2/100 in an adjacent room and ran a coax from it to the amp in the ham shack -- no trace of the problem. All tests were done on CW, monitoring the transmitted signal on another receiver (FT-1000MP) using narrow (250 Hz) bandwidth. The problem sounds like noise on the sidebands of the transmitted CW signal extending out at least +/-5 kHz from center freq. There's no reason to believe that this problem does not also exist on SSB. ========== "But if indeed that is the case, there must be a relatively easy, if perhaps not elegant, way of significantly improving this." ---------- It has been suggested that mu-metal shielding might alleviate the problem. I'm considering making mu-metal bottom and side covers for my K2. Another ham (W4FMS) told me he had the same problem with his K2/100 and Alpha 87A amp. He found that placing an aluminum cookie sheet between the K2 and amp with only 3 feet of separation resolved the problem. All things point in the direction of a K2 problem that is not phase noise. 73, de Earl, K6SE _______________________________________________ Elecraft mailing list Post to: [email protected] 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
