[BC] am receiver for monitoring at a 20 KW site.

[Dave Dybas]

It's not that big a deal if you have a pretty well shielded receiver with a
coax input.  You design a series pass filter for the freq you want to
receive, and then put a parallel cap or inductor across the series network.
Adjust the series LC for best signal at the wanted freq...then adjust the
parallel cap (or inductor) to reject the undesired (20KW) signal.
Essentially it's a diplexer type network.

Of course a little experimentation may be necessary to get the whole thing
properly tweaked.

Dave Dybas