sigh
Larsen, when can you and I hook up and do a video of the RIGHT way to
weather seal? hehehehe
First, John, I'm gonna assume that your guys know nothing so please take no
offence.....
The FIRST and MOST important step in a good water seal is the antenna! Jer
would be quick to remind me of that painful lesson as it applies to the old
Mobile Mark black 9dB omni antennas. The antenna connector at the bottom
was SCREWED into the mast below the weep hole. Water would eventually wick
down into the connection via the threads, no matter how good you were at
weather sealing. I LOVE those antennas, they work incredibly well, but they
just don't last.
You have to watch for things like people using those danged bulkhead
connectors with the flat sides on them. Also watch for the nut on the
outside of the connection. If it's not also covered there's a spot for
water to wick down into the connection.
When I run into those flat sided connectors I will stretch my mastic very
thin to make sure that I get the goop down into the cut down area. The down
side to this is that the mastic will eventually ooze into the threads and
make the connection REALLY hard to take apart. I always figured that a
connection that's easy to take apart will also be more likely to leak
though.
I try to get antennas that have a longer connector on them when I can. I
also require that antennas I use have room for a whole roll of tape between
the connectors and any other parts. If I can't put the tape on correctly it
will leak someday.
I tried using silicone on the connectors but that eventually shrinks and
there's something in it that corrodes the connectors. Bad idea.
I tried putting a layer of black tape on before I put on the mastic, then I
decided that that was a silly idea because that inside layer is the water
proofing and if it's easy to take off it's more likely to leak.
On the new Maxrad hpol adjustable beam sectors that I like so much I take
them to a machine shop and cut off part of the braketry so that I can seal
things up better. I'm not afraid to modify the mounting systems on antennas
if it'll let me do a better job of sealing them up.
I only use high end connectors. Times Microwave all the way.
Here's how I seal a connector:
Use one wrap of scotch 2228 mastic. Stretch it to half it's original width
and overlap each layer by half. This give you a two layer thick coating.
Start at the bottom about a half inch PAST the heat shrink. Heat shrink is
NOT water tight. It's a strain relief... Up near the connector bulkhead
end I will wrap the tape enough to make sure that there's a bit blob of it
around anything that might allow water in, especially the bulkhead it's
self. Then wrap back down to the middle of the connector.
Next I use Scotch 33+ tape (none of the cheap crap gets used anywhere here).
This gets two layers that are overlapped by half. Start so that your LAST
layer goes up. It should leave a pattern kinda like siding. You want the
water to run off of the seams not follow down into them. This needs to be
wrapped so that it's smooth, no creases allowed. A crease is an air gap,
air = water. Stretch the tape just enough to pull to all of the wrinkles,
too tight and over time it'll actually slide off of the connector. It may
do this over time anyway but once it's squished the mastic into all of the
nooks and crannies it doesn't seem to matter much. Not making your tape too
tight on the diameter transitions seems to help with the problem though.
I just don't have water problems anymore.
Things that I've seen/done that fail. Almost always.
Heat shrink. The glue hardens when temps drop and you loose the water tight
seal. Yes I know it works in water wells, but the temps there are steady.
Duct tape. Degrades in sunlight and many glues are water soluble.
Black tape alone, see above.
Silicone, shrinks and corrodes connectors.
Nothing. I know that there's a gasket in there, I know that the factory
says you don't have to seal them. They will leak.
Reusing antennas or connectors that got water in them. If you look closely
you'll see that the center pins have a discoloring. That's corrosion and
you'll never get a good connection out of them again. In fact I usually
chance the coax too.
Hope this helps!
marlon
Marlon
(509) 982-2181
(408) 907-6910 (Vonage) Consulting services
42846865 (icq) WISP Operator since 1999!
[EMAIL PROTECTED]
www.odessaoffice.com/wireless
www.odessaoffice.com/marlon/cam
----- Original Message -----
From: "John Scrivner" <[EMAIL PROTECTED]>
To: "WISPA General List" <[email protected]>
Sent: Friday, March 16, 2007 7:29 AM
Subject: [WISPA] Moisture Ingress
I would like a bit of feedback from those of you who have been installing
outdoor antennas for a while. I have a problem that I would like to see
fixed. It seems that after every long rain we see problems with the
occasional connection outside at the antenna getting water into it. We use
the Scotch seal mastic tape to seal the connections. The guys do not like
having to climb and they work hard to try to make sure we do not get these
problems and yet they come back. I would like to hear what you veterans out
there are doing to make sure the water stays out.
Thanks,
Scriv
--
WISPA Wireless List: [email protected]
Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless
Archives: http://lists.wispa.org/pipermail/wireless/
--
WISPA Wireless List: [email protected]
Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless
Archives: http://lists.wispa.org/pipermail/wireless/
