is turned off.
Alternately, the power cord may be connected to an available terminal on the fuse block or even to
a point in the wiring harness. Care must be taken, however, to guard against a short circuit condition
so when in doubt, please contact your vehicle dealer for specific information for your vehicle.
MOBILE ANTENNA CONNECTION
A vertical whip antenna is best suited for mobile operation. A nondirectional antenna should be
used for best results in any case. The base-loaded whip antenna will normally provide effective com-
munication or for greater range and more reliable operation a full quarter-wave whip may be used.
Either of these antennas use the metal car body as a ground plane and the shield of the base lead
as well as the metal case of the transceiver should be grounded. A standard antenna connector
(type SO-239) is provided on the transceiver for easy connection to a standard PL-259 coax plug.
Following the antenna manufacturer's instructions carefully will insure proper operation.
Whatever the type of antenna selected, it is important that it be properly adjusted and matched and
the connecting transmission line be in good condition so as to avoid a high VSWR (voltage standing
wave ratio). A VSWR over 2.5 results in reduced radiated power and may cause instability and damage
to the final output stage of the transceiver.
BASE STATION OPERATION
When the 77-857 is used as a base station, any Citizens Band beam, dipole, ground plane or vertical
antenna may be used. A ground plane type antenna will provide good coverage, and since it is es-
sentially non-directional, it is ideal in base station to mobile operation. From base station to base
station or point-to-point operation a directional beam will give greater distance even under adverse
conditions. The range of the transceiver also depends on the height of the antenna so whenever pos-
sible, select the highest location within F.C.C. limits.
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