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RE: Re: Weather proofing preamps at antenna feed points - Results



For the benefit of the group, here's the results of my request for info:

"I'd appreciate anyone's experiences on weather proofing preamps at antenna
feedpoints on Az-El rotators."

Many many thanks for all the many replies: lots of good ideas and anecdotes.

Specifically I _really_ do mean mounting _directly_ at the antenna feed
point - like behind the reflector of a helix for example, so the orientation
of the preamp could be anywhere.

Almost universally the advice is _not_ to rely on 'self-sealed' boxes.
Either through failure of sealant or corrosion of the case, these invariably
seem to be imperfect after some time. And then more likely than not water,
once in, will not get out!

Re-use of sealed cases specifically designed for outside mounting such as
some mast TV antenna preamps or old TV satellite dish boxes has been
suggested. However sometimes upon re-opening these cases [if they _can_ be
opened!], the hermetic sealing may fail for future use. Indeed, they may
have been pressurized inside in order to keep the moisture out. Once
opened....

For generalised (mast mounted, not directly at the feed point), other
suggestions are plastic food containers, upturned trash bins, sealed plastic
food bags.

Add to the above insect gauze for open holes, small holes to allow
condensation, rubber gaskets at coax entry points, and of course, non-acidic
sealant.

Another thing to note is that plastic enclosures which are not UV resistant
need painting, or else they will become brittle.

The use of ignition cable spray lacquer was certainly another new one on me.

Another idea I've been made aware of is the use of PVC plumbers piping and
accessories for weather protection. Again, attention to the sealing would be
essential.

FWIW I've used an upturned trash bin myself for a year without any problem.
Best thing about it is that there's so much room in it for all my junk, and
of course it only cost about $10. But you can't use this at the feedpoint!

Again, thanks all for your time in replying to my note.

73 Howard G6LVB

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