For coverage of all bands, 5 receivers would be required. Again I was thinking of the N3ZI boards, which would need pairs of crystals. Some back and forth thinking and looking at numbers, I was able to find pairs of well available crystal pairs. The suggested IF would be represented by the lower frequency (better ladder-filter) or cheaper crystal.
This is what I came up with: (suggested IF / suggested LO)
- 4.096MHz + 10.000MHz
- 2.097MHz + 12.000MHz
- 8.000MHz + 10.106MHz
- 6.144MHz + 15.000MHz
- 8.867MHz + 12.288MHz
- 14.746MHz + 10.180MHz (*)
- 4.194MHz + 24.000MHz
(*) 10.180MHz is a crystal found in 22 channel CB-radios.
Now, lets hope that the PCBs are a success, and a fully automatic propagation alert system will welcome the upcoming solar cycle.