Cobra Electronics 148 GTL Section II Specifications, General, Transmitter, Receiver, PA System

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Section II Specifications

Section II Specifications (Cont.)

GENERAL

 

Channels

40 AM, 40LSB, 40 USB.

Frequency Range

26.965 to 27.405 MHz.

Frequency Control

Phase Lock Loop (PLL) synthesizer.

Frequency Tolerance

0.005%

Frequency Stability

0.001%

Operating Temperature Range

-30° C to + 50° C

Microphone

Plug-in dynamic; with push-to-talk

 

switch and coiled cord.

Input Voltage

13.8V DC nominal, 15.9V max., 11.7V

 

min. (positive or negative ground).

Current Drain

Transmit: AM full mod., 2.2A. SSB 12

 

watts PEP output, 2A.

 

Receive: Squelched, 0.25A

 

Maximum audio output, 0.6A.

Size

2 3/8”(H) x 7 7/8”(W) x 9 1/4”(D).

Weight

5 lbs.

Antenna Conductor

UHF, S0239.

Semiconductors

3 field effect transistors, 45 transistors,

 

63 diodes, 6 integrated circuits, 1 two

 

color light emitting diode.

Meter (3-in-1)

Illuminated; indicates relative output

 

power, received signal strength,

 

and SWR.

TRANSMITTER

 

Power Output

AM, 4 watts.

 

SSB, 12 watts, PEP.

Modulation

High-and low-level Class B, Amplitude

 

Modulation.

Intermodulation Distortion

SSB: 3rd order, more than -25 dB.

 

5th order, more than -35 dB.

SSB Carrier Suppression

55 dB.

Unwanted Sideband

50 dB.

Frequency Response

AM and SSB; 300 to 2500 Hz.

Output Impedance

50 ohms, unbalanced

Output Indicators

Meter shows relative RF output power

RECEIVER

Sensitivity

Selectivity

Image Rejection

IF Frequency

Adjacent-Channel Rejection

AM and SSB RF Gain Control

Automatic Gain Control (AGC)

Squelch

ANL

Noise Blanker

Voice Lock Range

Audio Output Power

Frequency Response

Built-in Speaker

External Speaker (Not Supplied)

PA SYSTEM

Power Output

External Speaker for PA (Not Supplied)

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.

AM: 6dB @ 3 KHz, 50 dB @ 9 KHz.

SSB: 6 dB @ 1.1 KHz, 60 dB @ 2.3 KHz.

More than 65 dB.

AM: 7.8 MHz 1st IF, 455 KHz 2nd IF.

SSB: 7.8 MHz.

60 dB AM & 70 dB SSB.

40 dB adjustable for optimum signal reception.

Less than 10 dB change in audio output for inputs from 10 to 100,000 microvolts.

Adjustable; threshold less than 0.25 µV.

Switchable.

RF type, effective on AM and SSB.

±2.5 KHz.

4 watts into 8 ohms.

300 to 2500 Hz.

4 ohms, round.

8 ohms; disables internal speaker when connected.

4 watts into external speaker.

8 ohms.

and SWR. Transmit LED glows red when

transmitter is in operation.

(SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE)

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Contents Citizens Band SSB/AM 2-WAY Mobile Radio Channel Channel Frequency CB StorySection I Introduction Frequency RangeReceiver Section II SpecificationsGeneral TransmitterIgnition Noise Interference Section III InstallationLocation Mounting the ConnectionExternal Speaker Tuning the Antenna for Optimum SWRAntennas with adjustable screws set screws Antennas which must be cut to proper lengthControls and Indicators Section IV OperationControl Functions Operating Procedure to Receive Indicator FunctionsReceiving SSB Signals Operating Procedure to TransmitWire MIC Cable Alternate Microphones and InstallationFCC Warning Section IV OperationCode Meaning Section VI AppendixFEW Rules That should be Obeyed CodeIf You Need Service USE Channel 9 for Emergency Messages onlyPermitted Example Message Cobra Electronics Corporation 6500 W. Cortland Street Chicago, IllinoisOrder by phone Cobra Electronics Corporation