Why should anyone be committed?
If you can get past the misnomer "magnetic loop", there are several types of loop
antennas that work well for reception. Because efficiency isn't as much of a problem
for receiving as it is for transmitting (as long as the external noise level is still the
limiting factor) then construction is much simpler, and there is no reason not to use
multiple turns for the loop. I regularly use 4-turn loops for 80m that are 6 - 10 inches
in diameter and give reasonable performance over a 100kHz range (though with a
noticeable drop-off in signal strength at the edges.)
As you go higher in frequency you need fewer turns with wider spacing between
them to keep the self-resonant of the loop above your listening frequency. I have
a 3-turn loop that tunes about 5 to 15 MHz with a mica trimmer. Above that a
single turn loop such as this may be a better choice:
http://www.qsl.net/7n3wvm/mag-loop.htmlLoops typically don't work as well in a building or near power lines - they still pick up
signals, but often more via coupling to the wiring than on their own, which tends to
pick up more electrical noise. A remote loop some distance from the house, possibly
with a preamp and mounted on some sort of rotator, can give you the ability to null
out some noise sources.
There is also an untuned, preamplified loop design that I've seen, but haven't tried.