Topband: HiZ Delay and Preamp Boxes

[Mike Waters]

I know that some people swear by vents. But I personally have had terrible
results venting my Beverage antenna control enclosures. The enclosed relay
has froze up more than once from condensation, caused by humid air getting
inside and freezing (usually in the dark and in the dead of winter). But
since I switched to sealed plastic gasketed-lid enclosures, that problem
completely went away. They have clear lids, and I've never seen
condensation inside.

One thing that helps maintain the seal is completely filling all connectors
with silicone dielectric compound. Only my F connectors are waterproof; I
use tip plugs/jacks for the antenna and ground connectors. I force that
stuff into all the connectors until it appears inside the box at the other
ends. As the pressure differential between the inside and outside of the
enclosure changes with temperature and barometric pressure, this
non-hardening compound moves in or out, maintaining the seal. And I usually
add more of that whenever I disconnect and reconnect anything.

Also, just before putting on the lids, I heat up in inside with a heat gun
to help eliminate any moisture.

And I don't use desiccant. Never have. If at some point in the future I
ever did see condensation, though, I would add a small desiccant packet
before I would ever drill vents of any size, large or small.

Complete details with part numbers at this URL (scroll down past the
transformer photos):
http://www.w0btu.com/Beverage_antennas.html#Beverage_Antenna_Transformers

I know, I can already hear the keyboard clicks of all the people that are
going to tell me that I should use sealed DIP relays and vent my
enclosures. :-)

73, Mike
www.w0btu.com

On Fri, Jan 6, 2012 at 12:51 AM, Dennis W0JX <w0jx at yahoo.com> wrote:

> ...
> As for the new preamps, while the company states that they are
> water-proof, there is the possibility that humid air will condense inside
> and create water. Every beverage transformer box that I have built in this
> humid Ohio location has had corrosion problems from condensed humidity
> inside the “sealed” boxes. Water always finds a way in. So I plan to
> ventilate them...
>