Specifications

SMARTUNER MANUAL 30
SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© Nov2000 SGC, Inc. P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
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e) Horizontal wire antennas have maximum radiation broadside to the antenna
when the frequency is less than 1/4 wavelength. As the frequency increases
beyond 1/4 wavelength, lobes will appear in the radiation pattern with the
principal lobes becoming closer to the plane of the antenna as the length
increases. At all times, radiation will be minimal at the end of the antenna;
therefore, it should be located so that the ends point in directions where
communications are not required.
f) The V antenna construction minimizes the directivity of the horizontal antenna
and is recommended for all around coverage. In addition, the V antenna is a
compromise between vertical and horizontal polarization and will give good
results for communications with land or marine mobiles using vertical whip
antennas.
g) High voltages (sometimes exceeding 30,000v RF) are present on the antenna.
All parts of the antenna and coupler must be located or protected so that there
is no possibility of accidental contact.
h) Do not locate the antenna close to other antenna systems.
i) Make sure that the antenna is rigidly supported. The antenna will de-tune if it
sags or sways.
j) The connection from the coupler to the ground must be a small percentage of
the total length of the antenna. Do not let the length of the ground strap exceed
1.5 meters. Use heavy gauge wire or strap for ground connection.
k) Whip antennas should be connected with the minimum length of wire. (Do not
exceed 0.6 meters).
l) Do not locate the coupler farther from the transceiver than necessary. If the
distance exceeds 10 meters (30 feet), we recommend you use low loss coaxial
cable, such as RG-8 or Belden type 9943.
5.3 Ground Systems—General
The ground system (also called a counterpoise) is a key part of the overall antenna
system and is the primary cause of poor performance and the difficulty of adjusting the
coupler. A good ground is essential.
5.3.1 Vehicle Grounds
Connect the coupler directly to the frame of the vehicle. Ensure that a heavy strap is
used from the coupler ground lug and that the connections are cleared of all paint and
dirt so that the shiny metal is exposed. SGC always recommends that two grounding
bolts with star washers be used to ensure no ground resistance is encountered. Make