David,
Manual switching is only one of the options. There is also a small board you can add which can mux the 3 bits from the Raduino to all 6 sets of relays......but it would require a small code change. I was suggesting to use the codes 111,110,100, and 000 which the existing Raduino code supplies via TxA, TxB, TxC to select the 4 LPFs as today and add the remaining 2 when you get around to it. There is also no magic to 6x filters....it could be 5x or 8x filters or 12x filters if you add another select bit. 6x happens to fit readily on a 100mm x100mm panel.
The 4x LPF board version decodes the existing TxA,TxB, and TxC drivers just like the uBITX does today (and I have to reinstall K3). Those boards should be here next week.
73 kees K5BCQ
