[Elecraft] k3 switching supply

[Richard Fjeld]

On 6/16/2015 10:32 AM, Ignacy wrote:
> All switching power supplies emit something but whether their noise is heard
> or not depends on antennas. The noise is heard more with very close antennas
> and not all all with those farther away. Also more with unbalanced antennas
> especially is coax is part of the antenna system.
>
> There are many noise emitting sources that usually do not bother K3. For
> instance, P3 emits very strong noise when checked with antenna close to it.
> But I cannot hear any noise from P3 using my external antennas.
>
> I used MFJ 4125 and 4225. They generate weak moving streaks on P3 at my QTH,
> but no problem.  Jetstream JTPS31MB is smaller and a bit quieter.
>
> Ignacy, NO9E
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FWIW, a comment to say I have noticed in threads like this that I had 
been using the same power supplies
(several) that people are criticizing, and mine have been working 
perfectly.  Your analysis may be why.

One exception could be noted.  I do have a SS-30A that I had to solder 
the fan wires on the board to eliminate a whine
that could be heard in tx/rx when the fan would run, but no problem 
since.  Perhaps the operating frequency need be stated.

Dick, n0ce