Great to hear of your success, Jerry.
Good reception even at greater separation
between parallel L/C and the receiver is
primarily due to the strength of signal
leaping down the longwire and the inherent
sensitivity of the DSP receivers. One great
feature of this application is its simplicity in
maximising signal transfer.

The series L/C trap would work with other passive
antennas, but probably not so well as with the
longwire.

A loop would have sharp tuning, so the trap would
not be so necessary.

The setup would not be ideal with an amplified short vertical
like the SONY as the trap would need to come before
the preamp so that the unwanted signal is attenuated
before it can generate intermodulation products in the preamp.
The preamp with short vertical would probably work well
on its own, but might be susceptible to the powerful
local breaking through.

Outside, you might try a "shorter longwire" to a nearby tree
with the existing setup.Best would however probably be a
sharply tuned loop, or a longer ferrite (or even an FSL)
alongside the receiver, as detailed in many postings to this forum.
These exemplify simplicity and effectiveness par excellence.

73s

Michael UK