Yes, I think you got it. ?But better than adding a trim cap at C103 is to hook up the Raduino's CLK0 to replace the analog oscillator entirely, like the uBitx is doing for the BFO. ?Allard says he is looking into supporting this in a future sketch. ?This would allow the Nano to flip the BFO freq depending on if you want USB, LSB or CW, transmit or receive. ?All of those can affect where we might want the BFO placed, in addition to where the crystal filter happens to be centered on your rig. ?What's more, driving the BFO from CLK0 allows us to tune your CW carrier through the filter's range, and figure out what the shape of the filter is by monitoring the power of the outgoing CW carrier.
For now, if all you care about is sufficient drive when transmitting CW, I suggest you just put in a 10k resistor (instead of Allard's original 47k).
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On Wed, May 31, 2017 at 01:11 pm, John Smith wrote:
Is this a little bit more about what Peter was saying about "the relationship between the BFO crystal and the crystal filter bandpass"?
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