Cobra 29 WX NW ST User Manual - Page 4

Ignition Noise Interference, Antennas - range

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29 WX NW ST manual 3.3 6/15/99 2:53 PM Page 6 Antennas Ignition Noise Interference CB Antenna Note For optimum performance in passenger cars the ideal antenna location is on the center of the roof. Second choice is on the center of the trunk. Note Because many newer trucks feature fiberglass door skins, the outside mirror must be grounded to the chassis via a ground strap, if the antenna is mounted on the mirror bracket. CB Antenna Since the maximum allowable power output of the transmitter is limited by the FCC, the antenna is critical in affecting transmission distance. Only a properly matched antenna system will allow maximum power output. Cobra loaded type antenna models are highly recommended for most installations. For models with Weather Feature (WX), a Dual Band (Center Load/Base Load) antenna is recommended. Consult your Cobra dealer for further details, or call 773.889.3087 and speak to a Cobra representative. Note 3-way Combination Antennas are also available which allow operation of all three bands (AM-FM & CB),using a single antenna. However, this type of antenna usually results in less than normal transmit and receive range when compared to a standard-type "Single Band" CB antenna. Call 773889-3087 for further information. 1 A standard antenna connector is provided on the transceiver for easy connection. Marine Installation The transceiver will not operate at maximum efficiency in a boat without a ground plate, (unless it has a steel hull). Before attempting installation , consult your dealer for information regarding an adequate grounding system and prevention of electrolysis between fittings in the hull and water. 6 Use of a mobile receiver at low signal levels is normally limited by the presence of electrical noise. The primary source of noise in automobiles is from the alternator and ignition system. Typically, when signal level is adequate, the background noise does not present a serious problem. Also, when extremely low level signals are being received, the transceiver may be operated with the vehicle's engine turned off. The unit requires very little current and therefore will not significantly discharge the vehicle's battery. Even though the Cobra 29 WX NW ST has an automatic noise limiter, in some installations ignition interference may be high enough to make good communications impossible. Many possibilities exist and variations between vehicles require different solutions. Consult your COBRA dealer or a 2-way radio technician for help in locating the source of a severe noise. 7

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Ignition Noise Interference
Antennas
Use of a mobile receiver at low signal levels is
normally limited by the presence of electrical
noise.The primary source of noise in automobiles
is from the alternator and ignition system.
Typically, when signal level is adequate, the back-
ground noise does not present a serious problem.
Also, when extremely low level signals are being
received, the transceiver may be operated with
the vehicle’s engine turned off.The unit requires
very little current and therefore will not signifi-
cantly discharge the vehicle’s battery.
Even though the Cobra 29 WX NW ST has an
automatic noise limiter, in some installations igni-
tion interference may be high enough to make
good communications impossible. Many possibili-
ties exist and variations between vehicles require
different solutions. Consult your COBRA dealer or
a 2-way radio technician for help in locating the
source of a severe noise.
CB Antenna
Since the maximum allowable power output of
the transmitter is limited by the FCC, the antenna
is critical in affecting transmission distance.Only a
properly matched antenna system will allow maxi-
mum power output.Cobra loaded type antenna
models are highly recommended for most instal-
lations.
For models with Weather Feature (WX), a
Dual Band (Center Load/Base Load) antenna is
recommended.
Consult your Cobra dealer for fur-
ther details,or call 773.889.3087 and speak to a
Cobra representative.
Marine Installation
The transceiver will not operate at maximum effi-
ciency in a boat without a ground plate, (unless it
has a steel hull). Before attempting installation ,
consult your dealer for information regarding an
adequate grounding system and prevention of
electrolysis between fittings in the hull and water.
CB Antenna
7
Note
For optimum performance in
passenger cars the ideal anten-
na location is on the center of
the roof. Second choice is on the
center of the trunk.
Note
Because many newer trucks
feature fiberglass door skins,the
outside mirror must be ground-
ed to the chassis via a ground
strap, if the antenna is mounted
on the mirror bracket.
Note
3-way Combination Antennas
are also available which allow
operation of all three bands
(AM-FM & CB),using a single
antenna. However, this type of
antenna usually results in less
than normal transmit and
receive range when compared
to a standard-type “Single
Band” CB antenna. Call 773-
889-3087 for further informa-
tion.
6
1
A standard antenna connector is provided
on the transceiver for easy connection.
29 WX NW ST manual 3.3
6/15/99 2:53 PM
Page 6