Were one to put together a high performance RX with a
9MHz IF (Filters easily available from GQRP club),
how to deal with AM and FM resolution and the BW
over and above that needed for CW and SSB?

Down convert to, say 455 kHz?

Also, with the dream of an Eddystone-like tuning dial,
I wonder if any had thought of using the linear
digital measuring instruments, available up to about
a foot long for lathes, and providing a resolution
of 1/10th of a thou, the idea being that your
Arduino would read off the length of the dial to
determine the frequency of the digital VFO.

Perhaps a better approach would be to have a
rotary pulser with flywheel attached as the tuning
element to drive the digital VFO, with the tuning
dial being driven with a stepper-controlled screw
thread, to also drive the RF stage preselectors.

(Just musing about the 50+ years dream to build
my own comms RX :-) )

In my seemingly forlorn hope of stimulating
relevant and civilised discussion in these NGs.