Re: #ubitx-help Strong Audio Tones in and outside audio receive passband #ubitx-help
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Interesting observation that the 12 MHz USB clock oscillator is on nearly the same frequency
as the uBITX IF and BFO. If the BFO is offset to the high side of the IF passband it could well
be within audio range of the USB clock frequency. If this is the problem then it might be possible
to pull the USB clock crystal down with a small parallel capacitor. That should not make a
significant change in USB clock timing but could take it out of range of the receiver IF and BFO
frequencies. Some experimenting is probably necessary to tell how far to pull the crystal. It
would not be good to accidentally put it within the IF filter passband.
On Sat, Feb 3, 2018 at 1:47 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
I assume you mean changing the Arduino crystal, not cap.