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 mak e
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
Si n ce the maximum allowable power output of
the tra n s m i t ter is limited by the FCC , the ante n n a
is cri t i cal in affe cting transmission distance. Only a
p ro pe rly matched antenna sys tem will allow maxi-
mum power output. Co b ra loaded ty pe ante n n a
m odels are highly re commended for most instal-
l at i o n s. For models with Weather Fe a t u re (W X ) , a
Dual Band (Ce n ter Lo a d / Base Load) antenna is
re co m m e n d e d. Consult your Co b ra dealer for fur-
ther details, or call 773.889.3087 and speak to a
Co b ra re p re s e nt at i ve.
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
