After several less than satisfactory experiences with various outdoor sealed
boxes and junctions etc. I have had my ladder line, transmit antenna, and all
junctions completely exposed to the weather for the past 4 years with no
problems.
The problem was never as bad as the corrosion due to sealant, but I found out
that what was happening was that I was sealing water in! Obviously I was doing
something "wrong" but many of these containers had no lead-ins or holes in the
top, only sealed lead-ins with drip loops at the bottom.
I briefly had a NEMA rated junction box with watertight cover and seal over the
spark gap, but after water started accumulating in there, I simply removed the
cover. Every fall I go blow the leaves and bugs out.
On the receive antenna side... My K9AY relay board and termination resistor are
covered by a Tupperware dish but are exposed at the bottom. I had made a brief
attempt at sealing them inside the Tupperware but despite drip loops and all
the wires entering only at the bottom... I found water accumulating in the
Tupperware even though I swear it hadn't rained since I had installed it. I
don't have any fancy conformal coating or anything on the K9AY
relay/transformer/termination board.
Tim N3QE
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Don Kirk
Sent: Monday, March 18, 2013 8:17 AM
To: wa3mej@comcast.net
Cc: topband@contesting.com
Subject: Re: Topband: Using GE silicone as antenna sealant.
WA3MEJ said :
be very sure that if you pick GE silicone sealant.. (RTV or whatever you
> call it) DO NOT use the kind that has acetic acid in it.
>
This is a very good point, and this is the reason I use GE Silicone Sealant II
versus GE Silicone Sealant I. GE Silicone Sealant II is a "neutral cure
silicone" whereas GE Silicone Sealant is an acid or acetoxy cure silicone.
"Neutral Cure" silicone means no acids are released during the curing process
(note this information was obtained from the GE website).
73's
Don (wd8dsb)
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