Dan

Remember that this has to be a 'stealth' antenna as I live dead center in
the town with a lady councillor opposite, the town council office 75 yards
away and town hall about 150 yards away. This rules out low loss copper
pipe etc. Most of the small 'magnetic loop' antennas are intended for
vertical use which would also stand out like a sore thumb here. The
advantage of the wire loop is that many buildings here have wire around the
roof to deter seagulls, that means my wire would not be conspicuous.

When I modelled my 21' x 24' horizontal square loop with loading coils of
about 90uH in each side leg I got a feed impedance of over 300 ohms but
with -j5000 or thereabouts. The swr curved dipped nicely at 3.65 MHz to a
manageable level if I used a 4:1 balun and 300 ohm line feed. I reasoned
that as the natural loop resonance was between 20M band and 30M band I could
link out the coils and operate those bands too, although that would means
climbing up a ladder out of the rooflight rather more often than my old
bones like.

Richard (Dick) G4BBH