"Frank Dresser" wrote in message
...

"Kevin Miller" wrote in message
...

95% of the time it's early to late evening


As a test, try listening during the day. During the daytime, the skywave
signal should be strongly attenuated, leaving only the groundwave signal.
If the daytime signal is weaker but much steadier than the nighttime
signal,
it's almost certain the skywave signal and the groundwave signal are
interfering with each other in the evening.

The groundwave is the part of the wave that stays at the surface of the
earth. It goes out farther with increases in soil conductivity and
wavelength. The skywave is the part of the signal that gets bent around
back to the surface by the ionosphere. It comes back with to the surface
with differing phases and polorizations from the orignal signal. It will
add constructively or destructively to the ground wave at slightly
differing
times and frequencies. At certain distances, it all turns into a big
mish-mash, much worse than normal skywave variations.

I've never put much effort into minimizing such interference. But I can
make a suggestion. Since the interfering signal is coming from the same
direction as the desired signal, normal nulling techniques won't work.
However, putting the loop in a horizontal direction might null out enough
of
the groundwave to keep it from interfering with the nighttime skywave. I
expect this will null out most of the skywave, too, leaving you with a
weak
signal. Might be worth a try.

Phased antennas might work better, but I can't recommend anything in that
direction.

Frank Dresser




Makes me wonder how diversity tuning might work in any general BCB listening
scenario. Worth the effort?