Having tried a Beverage over a barb wire fence, it had poor
performance. A Beverage needs a significantly lower conductivity ground
underneath to develop the signal and barb wire is not that. Now that I
know better, I built an EZNEC model of a 10' high 600' Beverage over 3
barb wire strands 2', 3,' & 4' high, each insulated every 200', and the
model yielded an RDF of 11db at 1.8MHz. I had 600' of not insulated
barb wire off both ends that didn't have a noticeable effect. That RDF
sounds a bit too good, but shows it might work ok. It also appears
picking 200' sections for the model was fortuitous so perhaps the idea
can be further optimized. Not that it matters much for me as I sold my
ranch last fall.
Since cows are not Beverage friendly, you might try one of the various
phased vertical receive antennas that fit in much smaller spaces. I've
used the DX Eng 4 sq and the DHDL and had good results.
Grant KZ1W
On 2/10/2016 13:09 PM, Wayne Kline wrote:
Patrick
Your beverage direction N / S E / W are not the best direction for DX and I am not sure about the
coupling from the strands of barber wire below it ? ( I think this would be an
issue )
As for the magnetic loop..... unless you want to null out a local ground wave
Noise, even a small Beverage
you'll be better off... There are allot of info on the web regarding the
Beverage Antenna,
Wayne W3EA
To: richard@karlquist.com; towertalk@contesting.com
From: patrick_g@windstream.net
Date: Wed, 10 Feb 2016 14:56:00 -0600
Subject: Re: [TowerTalk] TowerTalk Digest, Vol 158, Issue 20
Rick, I have cross fences which run E-W and N-S diving the ranch into 4
equal square chunks of 40 acres each. These fences are, of course, 1/2
mile long. They are 5 wire barbed wire with T-posts roughly on 15 ft
centers. I was thinking of attaching extensions to the T-posts to get
more elevation for the Beverage as the T-posts' tops are at about 4 1/3
ft above ground. If te antenna were to pass by a gate it would have
to be elevated to at least 10 ft for a distance of 20 ft or so to allow
for gentle bends.
I am in a zone listed as 30 mmhos/meter conductivity as depicted by the
recently discussed map and do well with a Hy-Gain Hy-Tower multi-band
vertical atop a metal barn with no radials, just the barn as counterpoise.
I think maybe I need to study Beverage antennas significantly more
before committing much time and material to any "large scale"
experimentation. If a shielded magnetic loop would do nearly as well it
might be a better choice for the next experiment after the two in
process tower projects.
Patrick NJ5G
snip..
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