Section III Installation (Continued)
D. Try a different location on your car (keeping in mind the radiation pattern
you wish).
E. Is the antenna perfectly vertical?
F. Try a different location in your neighborhood. Stay away from large metal
objects when adjusting (metal telephone or light posts, fences, etc.).
NOTE
The COBRA 148GTL will operate into an SWR of 2 to 1 indefinitely
and sustain an SWR of 20:1 for a maximum of 5 minutes at rated
operating conditions.
EXTERNAL SPEAKER
The external speaker jack (EXT SPK) on the rear panel is used for remote receiver
monitoring. The external speaker should have 8 ohms impedance and be able to
handle at least 4 watts. When the external speaker is plugged in, the internal
speaker is disconnected.
PUBLIC ADDRESS
To use the transceiver as a public address system connect an external 8 ohm
speaker (4 watts minimum) to the PA SPK jack located on the rear panel. Direct
speaker away from the microphone to prevent acoustic feedback. Physical
separation or isolation of the microphone and speaker is important when operating
the PA at high output levels.
8
Section IV Operation
CONTROLS AND INDICATORS
There are thirteen controls and three indicators on the front panel of your
COBRA 148GTL.
A. CONTROL FUNCTIONS
1. OFF/ON/VOLUME (inner dual concentric). Turn clockwise to apply power to
the unit and to set the desired listening level. During normal CB operation,
the Volume control is used to adjust the output level obtained either at the
transceiver speaker or the external speaker, if used.
2. SQUELCH (outer dual concentric). This control is used to cut off or eliminate
receiver background noise in the absence of an incoming signal. For
maximum receiver sensitivity it is desired that the control be adjusted only to
the point where the receiver background noise or ambient background noise
is eliminated. Turn fully counterclockwise then slowly clockwise until the
receiver noise disappears. Any signal to be received must now be slightly
stronger than the average received noise. Further clockwise rotation will
increase the threshold level which a signal must overcome in order to be
heard. Only strong signals will be heard at a maximum clockwise setting.
3. RF GAIN CONTROL (inner dual concentric). Used to reduce the gain of the
RF amplifier under strong signal conditions.
9
