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Re: How to deal with Broadcast FM QRM

 

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I was able to decrease, but not completely eliminate, the 15kW AM station about 3mi from my house, by putting a .1uF from sweeper to ground on the volume pot, and a 1k in series from the sweeper to the input on the LM386. Those two together helped a lot.?

It¡¯s definitely coming in on the audio path into the 386, not through the RF stages.?

-Mark

On Dec 23, 2017, at 10:05 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

Raj is probably correct if you only hear that FM station when the volume control is set very low.
His extra resistor often cures the audio frequency oscillations in the LM386
that some experience with low volume settings.?


On Sat, Dec 23, 2017 at 09:16 pm, Raj vu2zap wrote:
Sounds like the Lm386 on Bitx40.
Put a resistor on the center lead of the volume control. Try any from 1-10K. This should cure it.
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