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Old November 7th 05, 03:34 PM
Denton
 
Posts: n/a
Default how to combat noise?

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