Sounds like you still have some RF getting in on the speaker cables
or maybe on the line-out cables. How much power do you run in
JT-65HF? I run JT-65 on 144-MHz at 1400w with no issues like you
have. I do not use a powered/amplified speaker, just and old
National speaker console from the 1950's with plain speaker wire. My
line-in and line-out cables are standard shielded audio patch cords
from RS. But then I only run 1.5mw to my transverter on 28-MHz, so no
significant RF coming out of the K3.
A quick test would be adding a .001 uF disc. ceramic bypass cap from
the center wire to ground at the K3 on the speaker. The toroid
apparently is helping according to what you write. Maybe shielded
speaker wire would help? I would guess the audio is already
transformer coupled to the K3 speaker output so an isolation
transformer probably would not help. I do think this looks like RFI.
73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
EME: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-60w, 3400-?
DUBUS Magazine USA Rep
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