A couple of antennas that work well at this qth...typical urban environment
with elevated power lines and assorted other racket.
Run a big horizontal loop around the place..feed with coax for recieve only
or twin lead plus transmatch for recieve/transmit. This is the one I am
currently using.
Previous antenna...which also works pretty good was a 100 ft bowtie doublet.
I used to run the doublet with vertical drops on the ends, but found that
any vertical drop on the ends of the antenna really picked up the racket. If
I left the vertical drops off the ends, I never did like the way the Johnson
Matchbox was coupling with the feedline...450 ohm...on 80 meters. I would up
with 10 ft end drops, then running a wire from the bottom of the end drops
back up to the feed point.
Tuned a lot better, broad banded and rejected noise pretty well.
"andy" wrote in message
oups.com...
Here is the situation: have an inverted V for 80m and noise level is
S9.. Not good really....
I did the next logical step and tryied magnetic loop for 80, reciving
only, indoors. That antenna failed awfully.... Noise was S8 but I could
not hear stations that were 9+10 on inverted V. Did'nt matter how I
tryied to rotate the loop, all there was is noise. So, indoors is right
out..
All that is left is roof. And that makes my situation interesting. It
is a big house with new metal roof, electrically bounded. 10X60 metres,
17 metres hight, angled about 20 degrees. Big ground plane indeed. All
I could figure is to get some sort of antenna to the roof so the roof
would act as a shield from all the noise generated inside the house.
That antenna would be for receiving 80m, can be narrow band (50KHz
ok). NVIS pattern would be prefered.
So, I have huge ground plane, lots and lots of noise below it, and need
a receiving-only antenna.
What would you do in this situation? Loop, magnetic loop, dipole, short
beverage perhaps???
Any advice is welcome. Right now I cant even figure if that roof is
acting like a shield or a big noise-sucking antenna..

Andrus

Denton wrote:
I used to run the doublet with vertical drops on the ends, but found that
any vertical drop on the ends of the antenna really picked up the racket.

Same as at my QTH. Anything vertical is noisier on receive.

If I left the vertical drops off the ends, I never did like the way the Johnson
Matchbox was coupling with the feedline...450 ohm...on 80 meters.

Because your feedline length was somewhere in the ballpark
of 1/4 wavelength and presented a very high impedance to
the Matchbox. Ladder-line feedline lengths for low-impedance
antennas need so be close to multiples of 1/2 wavelength,
a little over 100 feet on 80m. Unfortunately, a lot of
ladder-line-fed 80m dipoles and loops are closer to 1/4WL,
around 60 feet or so which may be worst case for limited range
tuners like Johnson Matchboxes and internal autotuners.
--
73, Cecil http://www.qsl.net/w5dxp