[TowerTalk] Preventing Water Penetration (was Aruba corrosion)

[Keith Dutson]

Rain is hardly a concern in Aruba.  It is a desert island with Arizona-type
cactus all over the interior.  The biggest problem with corrosion is likely
on the coastline where there is significant sea spray from constant trade
winds.

Keith NM5G


-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Frank Donovan
Sent: Sunday, February 13, 2005 10:02 AM
To: TOWERTALK at CONTESTING.COM
Subject: [TowerTalk] Preventing Water Penetration (was Aruba corrosion)

Vertical antennas constructed of telescoping tubing are difficult to protect
from water intrusion in any climate; however, its particularly important to
protect telescoping tubing joints and screw or rivet holes from salt water
intrusion near the ocean.

Examine any vertical object in a heavy rain (tower, vertical, coax cable or
anything else), and you will discover a steady stream of water flowing down
the object.  Flowing water enters the penetration points (e.g., telescoping
tubing joints or screw holes), and washes away Noalox or other materials in
the joints.
Near the ocean, salt will be deposited in the joints and screw holes.

A particularly effective way to solve this problem is to cover joints and
screw holes with shrink tubing.  The best choice is adhesive shrink tubing,
but almost any product will work well.  Near the ocean, its wise to use
shrink tubing over all joints and screw or rivet penetrations of
horizontally polarized antennas as well.  Be sure to leave openings at the
end of the elements that allow water to easily flow out.

In a temporary installation, use good quality electrical tape, properly
lapped so that water flows over each overlapping layer of tape (the tape
should should look like overlapped roof shingles after the last layer is
applied).

The same protection issue applies to outdoor coaxial and other cable
connectors.  Its wise to place outdoor connectors in a horizontal position,
to prevent flowing water from entering the connectors.  The cable at each
end of the connectors should turn downward, to form a drip loop.  Its more
difficult to prevent flowing water from entering connectors if they are
oriented vertically or if they are not protected by drip loops.

73!
Frank
W3LPL
donovanf at erols.com
_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.

_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk