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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.
Because most antennas are located outdoors, they will be subjected to harsh weather.
You don't have to worry about this if you are using SGC antennas because they are built to
last in harsh environments. If you are building your own antennas, be sure to use strong
materials, solder and connect them soundly, and waterproof them. All solder connections
should be electrically and physically solid. Then cover them with silicone bathtub caulking,
tape them tightly with electrical tape, and smear more caulking overtop. If you are installing
a long-term antenna, you don't want the joints to break down after only six months or a year in the air.
Noise and interference are the worst problems with HF communications. Because the radio signals can travel
thousands of miles around the world, the sources of noise can also travel great distances and plague HF users. In the
early days of radio, the users of the HF (and lower) frequencies found that the radio spectrum was filled with static
and thunderstorm crashes. In today's industrial and electronics-based world, those natural noises have been joined
by countless forms of man-made interference. There is little that you can do to avoid the natural interference, but
dodging the man-made interference is a fine science. The simplest rule is to stay away from houses or buildings.
Natural interference is caused by such things as solar activity and thunderstorms.
The worst form of natural interference is caused by lightning. The radio signals from the massive bolts of
electricity can easily propagate for hundreds of miles and cause what are typically known as static crashes across the
HF spectrum. Aside from avoiding operations during local thunderstorms, there is little that you can do to avoid this
interference. Snow and rain also create static that will cause communications problems.
HARSH ENVIRONMENTS
NOISE AND INTERFERENCE
All solder
connections should
be electrically and
physically solid,
and protected by
silicone sealant.
NATURAL INTERFERENCE
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