What output are you taking the audio from to plot these results? The line output signal goes through an isolating transformer. I think this saturates at quite a low audio level introducing non-linearity. You need to turn LIN OUT down to 2 or as low as you can get.
I haven't done the test you did, but if I look at a CW signal with a narrow filter selected I can see a ghost image of the signal on the waterfall at twice the audio frequency, well outside the IF passband. So I think the problem (if indeed it is a problem - nothing is perfect) is within the audio stages and particularly the line output. Ramiro Aceves wrote: > > Hello K3 fans > > I am a bit stranged and frustrated cause nobody has answered a single > word to my email "K3 RX spurs" posted on november the 20th. No comments, > no ideas.... > After some tests I have concluded that the spurs are 3rd order > intermodulation products. They only occur in DATA or CW. > ¿Can anyone please, try to reproduce those products in your K3/P3 or > K3/computer combination?. > > "DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz > Tune some steady carrier in shortwave. Tune the signal to place a > beautiful 1000 Hz on the waterfall > Tune your signal generator 10 Hz more than the broadcast carrier > frequency to get an audio signal 10 Hz over the 1000 Hz signal. Adjust > generator strenght to be similar to the broadcast carrier. > > You will see strong beautiful 3rd order products on 1020 and 990 Hz. > Swith to USB--> much more weaker 3rd order products or inexistent. > > http://ea1abz.ure.es/3erd-order.jpeg > > That is my K3 behaviour. Just want to know if my K3 is ok or not. > > Many thanks. I appreciate your effort in doing this test for me. > > 73, Ramiro, EA4NZ. > > PD: Volume at the speaker is zero to avoid vibrations inside the K3 > case. > > ----- Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-RX-spurs-tp5766108p5766251.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
