Cobra Electronics 148.GTL.ST Section I Introduction, Section II Specifications, Frequency Range

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148.GTL.ST.MANUAL 10/1/98 10:56 AM Page 5

Section I Introduction

FREQUENCY RANGE

The COBRA 148 GTL ST transceiver represents one of the most advanced SSB/AM two-way radios ever designed for use as a Class D station in the Citizens Radio Service. This unit features advanced Phase Lock Loop (PLL) circuitry, which is used in the AM mode and in the upper and lower single sideband modes, providing complete coverage of all 40 channels shown below.

Channel

Channel Frequency

Channel

Channel Frequency

 

in MHz

 

in MHz

1

26.965

21

27.215

2

26.975

22

27.225

3

26.985

23

27.255

4

27.005

24

27.235

5

27.015

25

27.245

 

 

 

 

6

27.025

26

27.265

7

27.035

27

27.275

8

27.005

28

27.285

9

27.065

29

27.295

10

27.075

30

27.305

 

 

 

 

11

27.085

31

27.315

12

27.105

32

27.325

13

27.115

33

27.335

14

27.125

34

27.345

15

27.135

35

27.355

 

 

 

 

16

27.155

36

27.365

17

27.165

37

27.375

18

27.175

38

27.385

19

27.185

39

27.395

20

27.205

40

27.405

The COBRA 148 GTL ST has a vastly superior receiver which includes an RF gain control and noise blanker circuitry effective in both AM and SSB modes., and an automatic noise limiter effective in the AM mode. The receiver also features increased protection against cross modulation and strong adjacent channel signals.

To obtain maximum performance please read carefully the descriptions and oper-

ating instructions in this manual.

Serial No.

Date of Purchase

Dealer Name

Keep this manual for detailed information about your Cobra CB radio.

SAVE YOUR SALES RECEIPT, THE CARTON AND “PACKING” MATERIALS FOR

POSSIBLE FUTURE USE.

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Section II Specifications

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

 

and SWR. Transmit LED glows red when

 

transmitter is in operation.

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Contents Citizens Band SSB/AM 2-WAY Mobile Radio SSB/AM 2-WAY Mobile Radio CB StoryGeneral Section II SpecificationsSection I Introduction Frequency RangeLocation Section III InstallationReceiver PA SystemAntenna Tuning the Antenna for Optimum SWRAntennas with adjustable screws set screws Ignition Noise InterferencePublic Address Controls and IndicatorsSection IV Operation External SpeakerSection IV Operation Receiving SSB Signals Indicator FunctionsOperating Procedure to Receive Operating Procedure to TransmitWire MIC Cable Alternate Microphones and InstallationSection IV Operation Section V Maintenance and Adjustment How SoundTracker WorksFCC Warning Code Meaning Activating/Testing SoundTrackerSection VI Appendix CodePermitted Example Message FEW Rules That should be ObeyedHOW Your CB can Serve YOU USE Channel 9 for Emergency Messages onlyIf You Think You Need Service Cobra Electronics Corporation6500 W. Cortland Street Chicago, Illinois Order by phone Mail toFax to