[Elecraft] K3 Harmonic Distortion

Jack Smith jack.smith at cliftonlaboratories.com
Mon Sep 1 10:08:27 EDT 2008


I will also try two simultaneous signals and see if I can duplicate your 
mixing observations.

Jack K8ZOA


Berni G0IDA wrote:
> Hi Everyone,
>
> I'm re doing the thread as this time I have some concrete findings to 
> share with you and wail be writing to Elecraft about this problem.
>
> My previous thread was about "ringing" in the audio but now it is 
> harmonic distortion at three times the frequency.
>
> I went around M0GJH's house house with my K3 and put it side by side 
> with his.
> I found the same distortion by listening on his radio too.
> A CW signal (as well as SSB) sounds a bit distorted and so we put the 
> output into his PC which was running Ham Radio Deluxe DM780 with a 
> waterfall display.
>
> Here you could quite clearly see that at 3 times any CW signal a 
> signal was present and was beating with the fundamental causing 
> distortion.
> The bandwidth was set to 1.5KHz and NR off. In fact with NR in there 
> was no difference of the 3rd harmonic it was still there and very 
> noticeable.
> Fundamental frequency received = 800Hz, Harmonic on waterfall display 
> = 2400Hz.
> The RX EQ was set to flat.
> Mode used was CW.
> Line out from the back was used.
>
> Andrew M0GJH had mainly presumed that signals which sounded a bit 
> "rough" were due to the station sending but in fact and it is my 
> belief that there is a problem with the K3 be it in the audio section 
> or DSP.... this I do not know as I don't have the knowledge.
>
> I hope there is a cure for this as it's frustrating listening to CW 
> with this sort of distortion.
>
> Cheers,
>
> Berni
> G0IDA
> #1474
>


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