On 4/5/2020 1:50 PM, Carl Yaffey wrote:
I have developed a loud hum with the KPA1500 on 17m and 15m. A slight hum on
20m. All other bands, no hum.
Because it's frequency dependent, I suspect some form of RFI. Start by
making sure that everything in your station is properly bonded.
http://k9yc.com/GroundingAndAudio.pdf
If that doesn't fix it, add ferrite chokes as described in
http://k9yc.com/KillingReceiveNoise.pdf
While the second reference is about killing RX noise, the same
principles apply to the problem you're having.
But do the bonding first.
One question though -- is what you hear HUM (pure 60 Hz) or BUZZ
(triplen harmonics of 60 Hz, like 180, 360, 540, etc)?
73, Jim K9YC
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