Cobra Electronics 148.GTL.ST Section III Installation, Receiver, PA System, Location

148.GTL.ST.MANUAL 10/1/98 10:56 AM Page 7

Section II Specifications (Cont.)

RECEIVER
Sensitivity	SSB: 0.25 µV for 10dB (S+N)/N at greater
	than 1/2-watt of audio output.
	AM: 0.5 µV for 10 dB (S+N)/ at greater
	than 1/2-watt of audio output.
Selectivity	AM: 6dB @ 3 KHz, 50 dB @ 9 KHz.
	SSB: 6 dB @ 1.1 KHz, 60 dB @ 2.3 KHz.
Image Rejection	More than 65 dB.
IF Frequency	AM: 7.8 MHz 1st IF, 455 KHz 2nd IF.
	SSB: 7.8 MHz.
Adjacent-Channel Rejection	60 dB AM & 70 dB SSB.
AM and SSB RF Gain Control	40 dB adjustable for optimum signal
	reception.
Automatic Gain Control (AGC)	Less than 10 dB change in audio
	output for inputs from 10 to 100,000 microvolts.
Squelch	Adjustable; threshold less than 0.25 µV.
ANL	Switchable.
Noise Blanker	RF type, effective on AM and SSB.
Voice Lock Range	±2.5 KHz.
Audio Output Power	4 watts into 8 ohms.
Frequency Response	300 to 2500 Hz.
Built-in Speaker	4 ohms, round.
External Speaker (Not Supplied)	8 ohms; disables internal speaker
	when connected.
PA SYSTEM
Power Output	4 watts into external speaker.
External Speaker for PA
(Not Supplied)	8 ohms.

(SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE)

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Section III Installation

LOCATION

Plan the location of the transceiver and microphone bracket before starting the in- stallation. Select a location that is convenient for operation and does not interfere with the driver or passengers in the vehicle. In automobiles, the transceiver is usu- ally mounted below the dash panel, with the microphone bracket beside it.

MOUNTING THE CONNECTION

The COBRA 148 GTL ST is supplied with a universal mounting bracket. When mounting the bracket and radio to your car, make sure it is mechanically strong. Also provide a good electrical connection to the chassis of the vehicle. Proceed as follows to mount the transceiver:

1.After you have determined the most convenient location in your vehicle, hold the COBRA 148 GTL ST with mounting bracket in the exact location desired. If nothing will interfere with mounting it in the desired position, remove the mounting bolts. Before drilling the holes, make sure nothing will interfere with the installation of the mounting bolts.

2.Connect the antenna cable plug to the standard receptacle on the rear panel. Most CB antennas are terminated with a type PL-259 plug and mate with the receptacle.

3.Connect the red DC power input wire (with the fuse) to +13.8V DC. This wire extends from the rear panel. In automobile installation, +13.8V DC is usually obtained from the accessory contact on the ignition switch. This prevents the set being left on accidentally when the driver leaves the car and also permits operating the unit without the engine running. Locate the accessory contact on most ignition switches by tracing the power wire from the AM broadcast receiv- er in the car.

4.Connect the black lead to -13.8V DC. This is usually the chassis of the car. Any convenient location with good electrical contact (remove paint) may be used.

5.Mount the microphone bracket on either side of the transceiver, using the two screws supplied. When mounting in an automobile, place the bracket under the dash so the microphone is readily accessible.

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