Bruce W. Ellis wrote:
"I am considering a horizontal loop antenna that would be "squarish"
(depending on the tree locations) and about 400` in circumference."

If you had more trees (octagonalish) would enclose more area with the
same wire. Radiation is a function of loop area.

Tesonant loops are often one wavelength in perimeter. 400` is about 122
meters. 160 meters = 525 feet. 80 meters = 262 meters. What band do you
prefer? If a loop`s perimewter is a little too short for resonance, it`s
inductive and can be tuned with a low-loss variable capacitor.

The 20th edition of the ARRL Antenna Book has a horizontal loop
"skywire" (squarish) on page 5-20. A 7 MHz loop at 40 ft. elevation has
about the same radiation as a 7 MHz dipole at 30 ft. elevation for
various azimuths. It might be worthwhile reading the Antenna Book
article before construction.

Best regards, Richard Harrison, KB5WZI