Uniden PRO 640XL - Manual (Page 6)

Mobile Installation
Plan the location of the radio and microphone bracket before starting installation.
Select a location that is convenient for operation and does not interfere with the
driver or passenger in the vehicle. The radio should be securely fastened to a solid
surface using the mounting bracket and self-tapping screws which are provided.
MOBILE ANTENNA
Since the maximum allowable power output of the transceiver is limited by the DOT AC. the antenna
is a very important factor affecting transmission distance, ft is for this reason that we strongly
recommend that you install only a quality antenna in your new CB radio system. You have
purchased a superior quality transceiver. Don’t diminish its performance by installing an inferior
antenna.
Only a properly matched antenna system will allow maximum power transfer from the 50-ohm
transmission line to the radiating element. We recommend that you use a SWR meter when
installing your antenna. Set your PRO $40XL to channel 20 and make adjustments to the antenna
until the meter shows SWR = 1. Your local dealer is qualified to assist you in the selection of the
proper antenna to meet your application requirements.
Forautomobile installation, the whip antenna may be used with goodeffect. The most efficient and
practical installation is a full quarter wave whip antenna mounted on the rear deck or fender lop,
midway between the rear window arid bumper.
A short 'loaded" whip antenna is more convenient to install on your automobile, although the
efficiency is less than a full quarter wave whip antenna.
For marine installation, consult your dealer for information regarding an adequate grounding
system and prevention of electrolysis between fittings on the hull and water.
GROUND INFORMATION
Most newer cars and small trucks use a negative ground system, while some older
cars and some newer, larger trucks may use a positive ground system. A negative
ground system is generally identified by t h e b a t t e r y terminal being connected to
the vehicle motor block, but if you cannot determine the polarity of your vehicle,
consult your vehicle dealer for information.
NOTE; This radio may be installed and used in any 12-voft DC negative
or positive ground system.
NEGATIVE GROUND SYSTEM
If you are operating on a negative ground system, connect the red DC power cord
from the radio to the positive '-I-" battery terminal or other convenient point and
connect the black power lead to the chassis or vehicle frame, or the negative
terminal of the battery.
POSITIVE GROUND SYSTEM
If you are operating on a positive ground system, connect the black DC power
cord from the radio to the n e g a t i v e b a t t e r y terminal or other convenient point
and connect the red power lead to the chassis or vehicle frame, or the positive"+"
terminal of the battery.