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The SGC Building, 13737 S.E. 26th St. Bellevue, Washington 98005 USA
P.O. Box 3526, 98009 Tel: (425) 746-6310 Fax: (425) 746-6384
© 1997 SGC Inc.
Like boats, aircraft fuselages are covered in various materials, conductive or nonconductive. As a result, you
will need to choose your ground location carefully. If the skeleton of the plane is aluminum and seems to be
electrically bonded throughout, attach the ground strap to the aluminum. As in any mobile radio installation, be sure
to wire brush the surface of the metal before attaching the ground strap. Likewise, after you have attached the
ground strap, spray a light coat of weather-resistant spray paint over the area.
Even if your ground connections are not in a location where they are in extreme weather, they should be
checked occasionally. All mechanical joints should be very tight or they will corrode under the presence of oxygen
and moisture. This light tarnish or rust will isolate the connection from the ground and ruin the system. In addition
to covering joints with a light coat of spray paint, it's a good idea to entirely encase the joint in a few globs of
silicone bathtub caulking that you can apply with your finger. For long, thin connections, such as wires, wrap
the connections very tightly with electrical tape, then cover the electrical tape with a light coating of silicone
bathtub caulking.
Ground systems which corrode due to natural age may be repaired on a periodic
basis. Outdoor conditions can be destructive to ground connections, but the worst-case
scenario is on marine vessels in salt water. As a result, you should check out the
connections every six months and if you have any question about their integrity, scrape off the caulking, unscrew the
bolt, wire brush the metal, and do it all over again.
Another problem with marine grounds (especially) is electrolysis. In this type of electrolysis, electricity is
flowing through a metal conductor and the water surrounding the conductor breaks down into oxygen and hydrogen.
As this process is occurring, the metals are also slowly being eaten away. As a result, you should check the metals in
the grounds to make sure that everything is working properly.
The radial ground systems at base stations are perhaps the most difficult systems to keep up regular main-
tenance on. Fortunately, base station grounds will usually last for a number of years--perhaps several decades. Even
so, you should regularly check the connection at the base of the radial system (where all of the radials connect to the
copper ground pipe). If this connection goes, all of those buried ground radials are virtually useless.
AIRCRAFT GROUNDS
GROUND DAMAGE, AGEING AND MAINTENANCE
Periodically check
ground connections for
corrosion or aging.
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