[Elecraft] K3: cw xmiting 2 signals 600hz apart: HELP

[Geoffrey Mackenzie-Kennedy]

Vic K2VCO wrote on Saturday, February 21, 2009 3:32 PM

>> The cause in the K2 case is that the CW sidetone oscillator signal gets 
>> into the VCO's varicap circuit and frequency modulates the VCO. The 
>> sidebands that I can see coming from my K2 in CW mode are symmetrical 
>> above and below carrier, one pair about 90db below carrier and the others 
>> much lower in amplitude. Their level varies with band.
>
> I had a bad case of this with my K2 and fixed it by replacing the quad DAC 
> IC.

-------------------------------------

Hi Vic,

I tried that with my K2, and it should have made some difference, but maybe 
the quad DACs that I bought fell off the back of a truck. So I have not 
bothered to do anything more because the sidebands are so far down, and not 
heard by anyone that I have asked to check when signals are S9+.

This question was asked by Doug about K3s, but I thought that I would 
mention the K2 in case the K3's sidetone signal does something similar.

73,
Geoff
GM4ESD