[Elecraft] K2/100 #4198 PA Stability Problem?

[Earl W Cunningham]

Andy, G4PIQ wrote:

"...On SSB makes the audio quite rough - on CW spreads with these
sidebands."
----------
This sounds like the same problem I have with my K2/100 while driving my
linear amp.  The electromagnetic field from the amp's HV transformer is
getting into the K2's PLL circuit and "modulating" it with 60 Hz.

Andy might be having the same problem with his K2, but because of
proximity to his 13.8V power supply which manifests itself more
noticeably with a K2/100 because the power supply transformer is
supplying more current than with a 10-watt K2.

This problem has been discussed on the reflector previously and the cure
is to space the K2 farther away from its power supply.

When driving an amplifier with the K2/100, the problem is even more
severe because of the larger electromagnetic field generated by the amp's
HV transformer while the amp is keyed.  In my case, even six feet of
separation is not enough.  With the K2/100 spaced 30 feet from the amp,
it is clean.  This is an unacceptable answer, of course.  Therefore,
because I refuse to transmit an unclean signal, until a solution is found
(mu metal shielding?) I cannot use my K2/100 when contesting or chasing
DX while driving a KW amp.

Others using their K2/100s to drive an amp should be made aware of this
problem.  Long ago Eric was going to run some tests drivng his Alpha 99
with his K2/100, but he never got back to me with the results of those
tests.

73, de Earl, K6SE