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
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
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