I am curious about the use and design of an unusual high
power, low band antenna which I saw recently while cycling
in France. I wonder if anyone knows anything about it.
The site is close to N89, about half-way between the
villages of Chevrol and Goujon in the vineyards north of
Pomerol and St. Emilion. A cell tower sits a few hundred
meters to the east-northeast.
The tower itself appears to be 250-300 ft (80-90m) tall,
mounted on a large insulator. It is very much thicker than
a normal guyed tower, suggesting an effort to expand the
bandwidth. The guy insulators are an unusual design,
indicative of moderately high transmitter power.
The tower is fed from a building with no windows
(transmitter, presumably) using "open wire coax": a circle
of wires perhaps 70-100cm in diameter (shield) with a single
central wire (center conductor). This design is typical of
high power MF or LF feedline. There is a stub section of
identical open wire coax attached to the feedpoint.
From the top of the tower, angling down to the ground at
45Â, is a length of two parallel wires separated by less
than 30 cm with spacing insulators. This line is NOT
electrically connected to the top of the tower; an insulated
section of perhaps 10m length separates the parallel line
from the tower top. Perhaps this is some kind of parasitic
reflector?
The site is fenced but has no identifying signs. In
addition to a standard French perimeter fence, barbed wire
fences enclose the tower base, guys, and the anchor for that
angled parallel line.
I have photographs (which, of course, I can't attach to
this email). If someone has a convenient website to which
the photos could be posted, that might help in resolving the
mystery.
You can get a good satellite view of the site and
neighborhood from Google maps. This long URL will be split
into several lines, so you'll have to paste it together in
your browser:
http://www.google.com/maps?f=q&hl=en&q=chevrol+france&ie=UTF8
&ll=44.949143,-0.188935&spn=0.014169,0.01826&t=h&om=1
This link will zoom in to the antenna field, where you
can see the tower, transmitter building to the lower right
of the tower, guy anchors, anchor for the parallel line (to
the northeast):
http://www.google.com/maps?f=q&hl=en&q=chevrol+france&ie=UTF8
&t=h&om=1&ll=44.950141,-0.188978&spn=0.003542,0.004565
Thanks.
-- Eric K3NA
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