Interesting idea, and it turns out that Hans of QRPLabs implemented something related in his QMX transceiver, which he presented at QRP ARCI Four Days in May recently prior to the 2023 Hamvention near Dayton, OH.
In the case of the QMX, there is a switching supply that potentially can produce birdies, so Hans nudges the primary switching supply frequency to move the harmonics when encountered a smidge (that's a technical term :-) ) to shift them out of the passband.
73,
-- Dave, N8SBE
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On 2023-06-20 08:19, Gary Anderson wrote:
I was bird hunting on the uBITX v6 a little over a year ago. This thread is akin to how I handled what I labeled as "stage 1" birdies.
/g/BITX20/message/92588It wasn't obvious (to me) if the IF shift needed could be calculated and applied.? Sure, I can manually switch it when I hear the bridie, after my ears settle a bit. This experiment lost my time priority, but was going to script a sweep in each of the bands (no antenna) at a low step size and and measure the peak audio frequency and level. Thinking with a graph of the data that the solution may become more obvious.? On the sBITX, it could more easily be handled in a hash table on the pi and a routine added to build that hash table.??
Rgds,
Gary
