Maintenance
The TH7DX antenna is designed to be relatively
maintenance free for most environments. All
hardware, is made of passivated stainless steel,
typically grade 304. The internal tooth-type lock-
washers used in this antenna are grade 410 stain-
less steel, and are slightly magnetic. The element
tubing clamps are grade 304 stainless
steel.
Most
other metallic parts are aluminum. All insulators
exposed to sunlight are made from U.V. resistant
black polyethylene or black Cycolac®.
If this antenna is installed in corrosive environ-
ments, such as within ten miles of salt water, or
in industrial areas with smog, several things may
be done to prolong the life of this product.
Hy-Gain now supplies genuine Penetrox®A-3
from Burndy Corporation for use as an anti-
electrolytic compound within element tubing as-
semblies. This prevents aluminum oxide from
forming on the aluminum surface, thereby main-
taining high electrical conductivity between ele-
ment sections, especially in coastal
environments.
Cut the cap off the tube of Penetrox®A-3. Have
some rags available to clean off excess from
tubing and hands. Be careful not to get this on
your clothing.
A light amount of clear lacquer or an acrylic
spray may be used to coat the exterior surface of
the element assemblies if heavy oxidation is like-
ly to occur. Do not use any coating on trap as-
semblies.
If installed near a sea coast, the solder lugs on the
pigtail wires should not touch the aluminum tube
or clamp directly. Each solder lug should be
between 2 stainless steel flatwashers. Tighten
these connections securely and completely coat
with Scotchkote® or RTV.
The internal tooth lockwashers should be replaced
with split lockwashers of grade 304 or better
stainless steel if your installation is near a sea
coast. Otherwise, these lockwashers should be
coated with Scotchkote® or RTV.
NOTE: Only use alchohol-based RTV (non-cor-
rosive).
When storing this antenna (or if awaiting instal-
lation), care should be taken not to damage any
trap assembly or allow any dirt or insects to enter
any trap assembly. Do not leave the elements in a
grassy area, as wet grass will stain the aluminum.
Before assembling the tubing sections, abrade the
mating surfaces with a wire brush or sandpaper.
Apply the anti-oxident to both surfaces, then
assemble joint. Wipe off any access material.
14Y-Gam' manufactures a high-power cur-
rent-type balun, model BN-4000B for beams.
It will handle 2000
watts
continuous duty
RTTY, SSB, AM, or 4000
Watts:! PEP,
and is
completely waterproof: You can obtain this
balun from your nearest Hy-Gain dealer.
Cycolac® is a registered trademark of Borg-Warner Chemical, Inc.
Penetrox® is a registered trademark of the Burndy Corporation.
Skotchkote® is a registered trademark of 3M
