I evaluated a few 10.7 mhz fm filters. Their stop-band rejection was hardly 50 dB, not enough for HF radio.
Btw, the sbitx scheme does not stop using a narrow cw crystal filter. The entire IF strip is broadband. So, you switch in the? cw filter (lets say at 9 Mhz) and change the LO and BFO by reprogramming the Si5351.
? David??
At 11 MHz, it is difficult to build a 10 khz filter without desoldering
all the caps and the matching transformers.?
However, if you are okay with the 3 Khz bandwidth, then it can be used
unmodified
On Fri 4 Jun, 2021, 9:50 PM David Forrest,
<drf5na@...>
wrote:
Couldn't sBITX do a 10kHz wide window with a relatively unmodified
uBITX without the 27MHz or 40MHz IF mods?
