SG-231 MANUAL
SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.
P.O. Box 3526, 98009 Fax: (425) 746-6384 Tel: (425) 746-6310
E-Mail: [email protected] Website: www.sgcworld.com
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Metal fencing of any type (e.g., a barbed wire fence along a pasture or under
telephone pole)
One hundred feet of wire thrown into a river or sea (e.g., under a trestle)
Metal drain culverts (e.g., along a highway)
Four to five cars parked with their metal bumpers touching
A sheet metal roof (e.g., hospital or public building)
As you can see from this list, there are an almost limitless number of options available
to install a high performance antenna system with only a small amount of wire and an
SG-231 Smartuner.
5.0 General Notes on Antennas and Couplers
1. The longer the antennas, the better the antenna performance. By doubling
the length of the antenna, an improvement of 3 to 6 dB can be expected in your
radiation or receiving characteristics. This is the equivalent of transmitting
with 400 watts, when actually you are using only 100 watts.
2. A ground for end-fed antennas can be effectively created by running radial
wires from the coupler point and laying them onto the ground. We
recommend for a good ground that 12 radials should be used and they be
about 1/3 longer than the antenna length. The number of radials can be
reduced; however, you need at least one. Efficiency pattern and radiation will
decrease in proportion.
3. Antennas will always perform better if the wire is of a large gauge. Never
use anything less than gauge 16. If gauge 6 is used, an improvement of 6 dB
can be expected over the 16 gauge. The radial ground wire should be at least
the same size as of the antenna wire.
4. The SG-231 coupler can handle antennas beyond the specified minimum
range of 8 to 80 feet and should be extended as much as possible. In some
cases, the antenna can be 300 feet or longer. In this situation, you may find
some tuning holes. The antenna can be made a little shorter or longer to
overcome the tuning hole on the frequency band you may have wanted to use.
5. Always install the antenna system as far away as possible from any electrical
or industrial noise source. Electrical appliance, electric motor, or fluorescent
lighting noise may cover up weak or even strong signals.
6. A remarkable antenna coupler, the SG-231 will tune practically any antenna
good or bad. Keep in mind that it is not the coupler that will radiate the RF
energy, it is the antenna. Therefore, use only good size wire and long antennas.
7. Never use a feed line or coaxial cable at the output of the antenna coupler.
The coupler functions to couple the radio to the antenna, not to act as a