Topband: Rx antennas

[Tom Rauch]

> To confirm the theory about noise reception from distant
sources, I took
> both my loop, and a short vertical with a FET preamp, out
into the country,
> away from local noise, for comparison.  Surprise
surprise - the signal to
> noise ratio on the signals from the ZL digi's was
identical on each antenna!
> The theory seems to hold up in practice!

That's the only place behavior is predictable.

> So while I have to agree with those who say that, in
theory, there should
> not be much difference between small loops and other
antennas, I do find
> that my loop works particularly well in a domestic
environment.  I like to
> think that this is because the arrangement I have gives it
good isolation
> from common mode signals picked up by the feeder, but for
that reason I
> would have thought that the flag would have given better
results than it
> does.  I don't really have the answer to that.

No one else does either. There isn't a person on this
reflector that can accurately tell others the field
impedance of local random nearfield noise or how antennas
will perform in random cluttered environments. The loop is
just as sensitive as any other antenna to problems. I
receive Europeans on a cliplead hanging from a preamp in my
shack better than with an in-shack loop. I have a ten meter
yagi that (on 160) sometimes has better S/N than a 160
dipole at 300 feet. All you can do is try them, it's just
luck if the environment is a radio-mess.

Some people have lucky 40 or 80 meter dipoles. Some have
lucky loops. Some have lucky low 160 dipoles. I have a ten
meter yagi that works OK on 160 receiving through random
dumb luck.

> The remote steerable array that I now have out in the
country beats the
> socks off all of them, not only because of its pattern
advantage, but
> because of its distance from most of the man-made noise.
One thing I do
> find though, is that the QSB is much deeper on signals
being received on the
> array.  Do other people using directional Rx antennas find
the same thing?

Do you mean the absolute signal level variation or your gut
feeling or mental impression of the depth of fading?

73 Tom