[GreenKeys] filters, dead or alive

[WB6BLV]

I notice that most here seem to run passive filters
rather than active ones using op amps.  Is there
some advantage to using these older LC circuits?
For me it has always been much easier to just
adjust a single pot to set the filter right on the money.
Filter gain, Q, and of course center frequency are all
set with ease in most active filters, using three resistors.

For MARS I had a set of passive filters made by
Grant Storey, and they worked well, but not as well as
simple active filters.

Sidenote -  yes actual shift is the critical parameter for
HF vice actual frequency for VHF AFSK.  That is why
the URA-8A (CV-89) will work well on HF using the
lower in frequency tone pairs.  Anybody running the 89
in diversity mode?  Getting dizzi from the 'flippin line'?

John
WB6BLV at inreach.com