YOU AND YOUR AN TEN NA
Three main components comprise a typical Citizensband installation. They are: your transceiver, an
antenna, and the coaxial cable which connects the antenna to the transceiver. It is important that ali .
three pièces are installed correctly to give the best possible range and reliable performance. We hope
this pamphlet w ill be helpful for you to realize the maximum performance of your installation.
ANTENNA
For several reasons, it is impossible to exactly PRE-TUNE an antenna at the factory.
A general range of tuning is done which may suffice, but for best performance, an antenna should be
turned after it is installed.
Most antennas hâve some form of tuning capabilîty. Usually, this involves the whip section sliding
into a coil, spring, or metal section. This allows the antenna to be adjusted to the exact frequency
desired. We cannot stress enough the importance of tuning your antenna. The measure of an antenna's
performance is its "SW R " (standing wave ratio).
"C O A X "C A B L E
Coax cable is used in ail Citizensband installations. This cable transfers the power from your
transceiver to the antenna. The output of your transceiver is 50-52 ohms. Your antenna is designed
to be 50-52 ohms. For this reason, RG58/U or RG8/U cable is used because it also is 52 ohms and
matches the antenna to the unit. The frequency of the antenna is very important in this area because
a mis-tuned antenna can disrupt the system balance. If this balance is disrupted, standing waves are
generated on the coaxial cable, which results in a loss o f power in your transceiver.
UNDERSTANDING SWR (Standing Wave Ratio)
In theory, your transceiver has a 50 ohm output and your antenna is 50 ohms. If a 50 ohm cable
(such as RG58/U or RG8/U) is used, ail the power from your transceiver w ill be transmitted via the
coaxial cable and radiated by the antenna. Underthese conditions, the SWR (standing wave ratio) of
your antenna system would be 1:1. In practice, the antenna must be 50 ohms and tuned to the exact
channel. This condition seldom exists and standing waves are set up on the cable. This SWR robs you
of power and likewise range. While 1:1 is not always possible to attain, you should tune your antenna
system so the SWR does not exceed 1.5 to 1 or at maximum 2 to 1. Неге are some examples o f the
power losses fo r various SWR ratios:
- 12 -
