Hi:
I'm also a fan of the BITX40/20 architecture and have had good luck on other bands.? One thing I did was to create a "mainframe" of the core of the design that starts right before the first mixer and ends right after the product detector/balanced modulator.? In my own experimentation it seems like 90% of the modification are happening in the "peripherals" around the core (different LC filters, different PAs, different bands, different audio/mic configurations, different software, different enclosures, etc.) so I am able to cover more ground without needing to re-build the inside of the inside every time.
My core uses two SI5351 ports so the BFO is tunable just like the VFO making it easy to fool with different IFs, filter widths, etc.? I also based the chain on the W7ZOI TIA amp which seems to improve performance a lot.? So there is a bit of the uBITX design incorporated here I guess.? The crystal filter is on a daughter card for easy swap.? I'm using ADE-1 mixers on both sides which are easily/cheaply obtained on E-Bay.? Adjustable gain VFO/BFO buffers (ala N6QW LBS design).? The core is 100% symmetric so it's quick to build and test.
73s,
Bruce KC1FSZ
