[Elecraft] [K3] Noise from P3

[Jim Brown]

On 3/23/2011 1:30 PM, John Lemay wrote:
> Yes, I can "home in" on the noise with great certainty !

That indicates that the noise is being radiated by the P3 or something 
attached to it, and picked up on your antenna (and not picked up on K3 
wiring).

The comments by others that ferrites on the power cable killed the noise 
suggest that that cable is doing the radiating. Now, I wouldn't rule out 
the coax as a radiator if someone has choked the power cable and still 
heard noise -- with RFI, always assume that there could be more than one 
coupling mechanism.

Again, let me emphasize that a ferrite core is a low Q parallel resonant 
circuit. Most single #31 or #43 cores are, by virtue of their size and 
shape, cause a single turn to resonate close to 2M, while more turns 
move the resonance down to lower frequencies. This a problem on 2M is 
better solved with multiple cores rather than multiple turns, whereas 
problems on 6M are better solved with two turns and on the HF bands with 
more turns.

73, Jim K9YC