I have been thinking that the receive audio from my K2 (#4314) was just OK, especially on CW when compared to other rigs including a Drake R8 and a K1. It's not terrible by any means, just not as good as it might be.
Today I fed an S9 CW signal into Spectrogram and find that its third audio harmonic is down approximately 10 dB from the fundamental. The 5th, 7th, 9th, are down about 4 db sucessively from the next-lower odd harmonic. This is easier to see than to say: http://world.std.com/~rice/k2_harmonic_distortion_05.jpg This is observed when driving headphones or speaker to a comfortable listening level (red trace on the spectrogram above). Decreasing the RF or AF gain so that the audio level decreases ~30 dB (blue trace on the spectrogram) eliminates the problem, but the signal is then too faint to copy effectively. The vertical red line is the center frquency of the widest CW filter (1.2 kHz) set per N0SS's instructions. AGC on/off and DSP on/off make no difference. It seems to be pretty far downstream in the audio chain. Sidetone audio behaves the same - no worse. Is this level of harmonic distortion normal? If not, what should I look for to correct it? Thanks and 73, Ken Rice K3VV Coopersburg, PA _______________________________________________ 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
