The IF is 12.288 MHz which works well for 40 meters because it far away from the LO and band frequencies. For LSB the LO is in the 5 MHz range.
The crystals I used for the filter are CTS MP122's: Regarding crystal filter design: yes, it is a pain.
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There are birdies, but they're mostly low level and manageable since they get covered up by atmospheric noise. 7296, and 7261 are a couple of big ones.
7168 seems? be an emission from the Raspberry pi Pico and it is modulated at ~50 Hz.
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The 26 MHz reference oscillator is a TG2016SMN 26.0000M-MCGNNM3 made by Epson. Digi-key part number SER4426CT-ND.
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No SI5351 module used here ;). The SI5351 chip is soldered down to the VFO board I designed.? The only module on the VFO board is the Raspberry Pi Pico. That has a QFN package and I don't have the equipment nor the dexterity to solder QFN's properly.
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Steve
WA6ZFT
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hwstar