> -----Opprinnelig melding----- > > 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.
Just a few questions to understand your measurement: How did you feed the signal into your PC for analysis, using a microphone or from e.g. the headphone output? In my experience, it is very easy to overload the sound card in the PC. The result is the same kind of distortion that your plot shows. A simple check is to try to adjust the PC input level (software controlled slider) and see if that changes the distortion. 73 Sverre LA3ZA http://www.qslnet.de/la3za/ _______________________________________________ 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