Jamie,
The Heil headset will plug directly into the rear panel jacks - why not
give that a try as an added piece of evidence that it is not the microphone.
Most likely, something is being picked up on those long microphone
cables and is not a K3 problem at all. Are all the mic cables
shielded? Are all the cable shields connected to the plug/jack shell?
They should be.
I have not investigated the W2IHY equipment, but my understanding is
that it is setup primarily for pro mics which use balanced AF lines for
the mic audio. My suspicion is that there is something awry with the
balanced to unbalanced arrangement when used with unbalanced line
microphones such as you have there.
As far as why it shows up only when the PA turns on, I can only
speculate there too, but remember that there is more gain in the
transmit stages when the PA turns on, and that added gain may make any
small AF line pickup more pronounced in your transmit signal. If it
were from RF coupling into the audio, it would vary smoothly from low
power to high power and all RF levels in between - you indicated only
that it was there with the PA on, but did not say that it got worse as
power was increased.
73,
Don W3FPR
James C. Hall, MD wrote:
Bob:
As a follow up, I doubt it's the Goldline mic/cable itself, as I get the
same hash with a Heil headset plugged into the switcher.
73, Jamie
WB4YDL
From: James C. Hall, MD [mailto:[EMAIL PROTECTED]
Sent: Friday, June 6, 2008 04:27 PM
To: [email protected]
Subject: [Elecraft] K3: 6M SSB audio hash
Hello: I've noticed some audio hash on my SSB signal on 6M only when the PA
relay kicks in at 13 watts. My long microphone cable goes to a
Multi-Switcher -> W2IHY Noise Gate/Equalizer -> Heil Goldline microphone.
This completely disappears when I use a Kenwood hand mike direct to the K3.
Thinking that this was a classic "RF on the line" problem, I clipped on
multiple ferrite chokes with many turns on the cable coming from the K3, the
Goldline mike, and in between the switcher on noise gate. This didn't even
slow it down ! Hmmm. Interestingly when the PA relay is off at 8 watts,
there is absolutely no hash. For now, I'll just use the hand mike on 6M
(which requires a bit more mike gain) to keep a clean signal. Has anyone
else noticed this ? Got a solution ? 73, Jamie WB4YDL
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