Its not a drop in.? The filter would likely be hard to find and costly or for a one off salvage from?
an old junker commercial radio.?
I think Kenwood radios used a 63mhz filter or maybe ICOM.? so lets do a thought
experiment on what needs to be done.
The filter would need to be matched and like data for it will require experimental testing.
The T30-2 toroids could be reused and rewould and the cap for the L-networks changed
as needed.? The entire string of 3904s [all 6 of them] in the 45mhz section would have
to be some thing like 2n2369, or better BFR106s.?
Then the firmware has to be revised as the first lo needs to be higher to start maybe
65mhz and go up from there.??
So yes it can be done.? I don't have such a part so thats ruled out.? So for a one off
maybe, doesn't help everyone though. and even if the filter was not too expensive?
thats a lot of SMT and through hole work plus a new firmware.? At the production
level it could add significant cost and interrupt the product flow as you have all the
material in place and likely paid for.
Right now the most feasible option is bandpass filters and switching.? Cost wise the
parts are cheap is SMT inductors are used.? The trick there is drop in and play no
manufacturing tuning.
Allison
