Topband: RX antennas

[Tom Rauch]

> I have found that a 40 meter dipole (@60 ft) is very
competitive
> with beverages.  I figure this must be because the noise
> is mainly vertically polarized.  I would like to try

I wonder why.

Any beverage I've had just kills any dipole for receiving.
Even my dipoles at 300 feet. As a matter of fact, my 160
meter Beverages are closely competitive with my three
element full size 40 meter Yagi up at 140 feet on 40 meters!

Noise is randomly polarized. It is earth effects that cause
arriving local noise to be mainly vertically polarized, and
it must be local noise propagated through groundwave
propagation. Attenuation along the earth filters out any
horizontally polarized noise, just like it does horizontally
polarized signals from intentional transmitters.

> an array of short dipoles to get horizontally polarized
> directivity.  I haven't seen this idea written up anywhere
> and am curious if anyone has seen any data on it, pro or
con.

I've been unsuccessful at phasing or using low horizontally
polarized antennas, but I only tried a few times. The first
time was in the 70's in Ohio. More recently I tried it here.
What I found is the arriving desired signals are low angle,
and horizontally polarized antennas kill the signal as well
as they do the noise.

There might be an exception at some locations, or an
exception at sunrise or sunset when DX signals arrive with a
high angle.

I suppose it is worth a try if you have dominant local noise
that propagates in along the earth's surface.

73 Tom