In article kImTg.111$pS3.23@trnddc01,
"Dale Parfitt" wrote:

" That was a self defeating test. The idea here is that you will have a
lower noise floor in a locally noisy area with a shielded loop than a
dipole antenna. There is going to be no advantage to using a loop over
a dipole in an electrically quiet area.

A shielded loop is not better at picking up a distant signal than a
dipole but is less sensitive to local noise generators so in an area
with high local noise you would have better signal to noise than a
full size dipole antenna.

Please see:
http://www.w8ji.com/magnetic_receiving_loops.htm

A nice page written by some amateur drawing wrong conclusions. Following
his logic coax cable would not shield the center conductor either for
example since the coax has to be open on both ends. He quotes a lot of
good information and then spouts conclusion that don't follow.

I don't have the patience to read the whole page but I scanned through
it and for starters he does not seem to distinguish between far and near
field energy. Far field has equal energy in the E and H fields so two
antennas, example dipole and loop, that are strongly couple to one field
and not the other generate the same power. No real difference then
between antennas that are strongly affected by one field and not the
other to far field signal or noise.

Near field is a different story. Near field is what the local noise
makers generate the most of and the electric tends to propagate farther
than the magnetic from the source so you want to use an antenna that is
sensitive to the H field for the same reason you try to get an antenna
as far away from local noise sources as possible. You can see the logic
in that right?

And let's not forget about that very handy null in the loop pattern. I
use that all the time on the AM portable with its built in loop stick
antenna that is not even shielded.

--
Telamon
Ventura, California