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Antenna Bonding/Surface Coating - RF Cafe Forums
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Khess
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Post subject: Antenna Bonding/Surface Coating
Posted: Fri Feb 09, 2007 2:49 pm
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Joined: Thu Feb 08, 2007
7:47 pm Posts: 1 Location: Plano, TX
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Can anyone comment on the following? After inheriting
a partial design (with antennas already ordered
and the tower designed by a 3rd party), I have to
mount Dayton Grainger UHF omnis, pn FM10-376-2 (same
as Rockwell Collins pn 013-1656-010) to an existing
mounting bracket, already welded to an existing,
painted steel tower. After taking the mounting bracket
to bare metal, what is the best non-oxidizing/conductive
coating that I can apply to the mounting bracket
prior to bolting the antenna base on? Without any
coating, I will have steel to aluminum. (Yes, I
know.) I can not send the bracket out to a fab
shop for plating so this has to be done in situ.
Not that it makes any difference, but these antennas
have the old fashioned, radial ground rods on the
antenna base. And yes, I have installed a Polyphaser
lightening protection system. Any ideas and/or
specific part numbers would be greatly appreciated.
Thanks.
_________________ Purdue1980
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nubbage |
Post subject:
Posted: Mon Feb 12, 2007 7:55 am
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General |
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Joined: Fri Feb 17, 2006
12:07 pm Posts: 218 Location: London UK
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There are 2 methods I have used both for the situation
you describe and also for use on a sailboat in a
sea-water environment, which had galvanised steel
fittings that had passed their sell-by date.
The first, that I would recommend for the tower
steel, was some paint-on so-called "dry galvanising"
which is much used in farming for steel gates and
such. I was given a tin that had lost its label,
so I have no idea who makes it. I guess it was a
very zinc-rich paint. As a barrier between
the ali tube boom and the steel tower I have used
teflon ptfe tape as used in plumbing for union/joint
wrapping. This is about the only barrier that has
a long life under ultra-violet sunlight radiation.
It is cheap and can easily be wrapped around the
boom tubing. Then a galvanized clamp to the tower
gives an intermediate electro-chemical voltage half-way
between steel and ali. I have even used this tape
as a barrier between ali and copper, with no failure
during twenty years installed.
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Posted 11/12/2012
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