On 11/21/14, 7:40 AM, Hans Hammarquist via TowerTalk wrote:
No Ron, it's worse. I have a square opening in the wall of my shack that is
covered with a metal plate. There are holes in the plate that hold the bulkhead
feed-troughs.
My idea was to have easy access to the various feeders that goes up the tower.
I plug in the coax from the trx whatever antenna I need for the moment. All the
connectors are open to the air in the shack. I thought it was an excellent idea
but realize now that it might not have been that excellent after all.
As the plate has no insulation it will get cold in the winter and I will have
condensation on it AND the connectors. If (I am sure it will) the condensation
goes through the connectors I will also have water on the outside with
following corrosion. :( As the connectors are sealed, the water will have no
way to get out.
here's a sort of different approach..
it's a small plate, I assume.. What about bolting a small resistor to it
and running a bit of current to keep it warm. A watt does a surprising
amount to keep things a bit warmer than the surroundings and keep it
relatively dry.
You could get one of those reptile strip heaters, for instance.
Or just put one of the wall warts sure to be in your shack near it
1 watt, for 8640 hours (a year), is 8.64kWh, and about $3/yr at my
0.34/kWh .
Put a layer of styrofoam board over the outside with holes for the
cables, and the heat loss through the plate will be dramatically reduced.
Similar schemes can be used to keep conduit dry.. It just needs to be
enough heat to change the equilibrium over the long run, because your
goal isn't really to prevent any condensation, it's to keep water from
accumulating.
When the water condenses it gives up heat of vaporization to the conduit
and wires (warming them), and when it evaporates, the wires/conduit cool
a bit. All you need to do is add a bit of net heat and while water
might condense when it gets cooler, it will evaporate again fairly quickly.
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