[Premium-Rx] receivers with 20Mhz IF?

[John Miles]

It won't be.  The resolution-bandwidth filters are in the 851B itself, so
you'd need to downmix the 21.4 MHz signal to 20 with a 1.4 MHz oscillator.

Apart from that, I don't see why an 851B wouldn't make a serviceable
panadaptor, as long as you can find a way to drive the receiver LO from its
sweep output.  Perhaps a varactor-tuned VCO could be made to sweep from,
say, 1200 kHz to 1600 kHz.  Drive it from the 851B (which probably has
something like a 0-10V sweep output corresponding to beam position) and use
it to heterodyne the 21.4 MHz receiver LO to the nominal 20 MHz IF.  The
851B's own filters will take care of the image.

-- john KE5FX

> Hi Eugene:
>
> You might use the 21.4 MHz output that's common on many receivers if the
> bandwidth on the SA 20 MHz port is wide enough.
>
> 73,
>
> Brooke Clarke, N6GCE
>