Cobra Electronics 25 LTD ST operating instructions Specifications, Channel Channel Frequency MHz

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Specifications

FREQUENCY RANGE

The COBRA 25 LTD ST transceiver represents one of the most advanced 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 providing complete coverage of all 40 channels as 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

27.055

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 25 LTD ST has a vastly superior receiver which includes noise blanker circuitry and an automatic noise limiter. The receiver also features increased protection against cross modulation and strong adjacent channel signals.

To obtain maximum performance please read carefully the descriptions and operating instructions in this manual. Fill out below; keep for your records.

Serial No.

Date of Purchase

Dealer Name

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

SAVE YOUR SALES RECEIPT, CARTON AND PACKING FOR POSSIBLE FUTURE USE.

2

Specifications (cont.)

 

 

GENERAL

 

Channels

40

Frequency Range

26.965 to 27.405 MHz.

Frequency Control

Phase Lock Loop (PLL) synthesizer.

Frequency Tolerance

0.005%.

Operating Temperature Range

-30¡ C to + 50¡ C.

Microphone

Plug-in dynamic.

Input Voltage

13.8VDC nom.(positive or negative ground).

Current Drain

Transmit: AM full mod., 1.5A (maximum)

 

Receive: Squelched, 0.3A; full audio output, 1.2A

 

(nominal).

Size

8 5/8Ó D x 7 9/32Ó W x 2 13/64Ó H .

Weight

4 lbs.

Antenna Connector

UHF, SO-239.

Semiconductors

26 transistors, 26 diodes, 4 integrated circuits.

Meter

Illuminated; indicates relative power output and

 

received signal strength.

TRANSMITTER

 

Power Output

4 watts.

Modulation

AM (Amplitude Modulation).

Frequency Response

300 to 3000 Hz.

Output Impedance

50 ohms, unbalanced.

RECEIVER

 

Sensitivity

Less than 1 µV for 10dB (S+N)/N.

Selectivity

6dB @ 7 KHz, 60 dB @ 10 KHz.

Image Rejection

80 dB, typical.

Adjacent-Channel Rejection

60 dB, typical.

IF Frequencies

Double Conversion: 1st: 10.695 MHz.

 

2nd: 455 KHz.

Automatic Gain Control (AGC)

Less than 10 dB change in audio output for inputs

 

from 10 to 50,000 microvolts.

RF Gain Control

Adjustable for optimum signal reception.

Noise Blanker

RF type.

Squelch

Adjustable; threshold less than 1µV.

Audio Output Power

4 watts.

Frequency Response

300 to 3000 Hz.

Distortion

Less than 7% @ 3 watts @ 1000 Hz.

Built-in Speaker

16 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

8 ohms, when PA-CB switch is in PA, the PA speaker

(Not Supplied)

also monitors the receiver; separate jack provided.

(SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE)

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Contents Citizens Band WAY Mobile Radio Cuts Static coming in, adds Punch going out CB StoryChannel Channel Frequency MHz SpecificationsInstallation LocationMounting and Connection Temporary Mobile Operation CB AntennaIgnition Noise Interference Base Station Operation Operation from 120VAC, House CurrentControls and Indicators OperationFront Panel Operating Procedure to Receive Press-To-Talk MicrophoneRear Panel How SoundTracker Works Operating Procedure to TransmitCode Meaning Maintenance and AdjustmentAdjustment Warning AppendixIf You Think You Need Service Few Rules That Should Be ObeyedHow Your CB Can Serve You Limited Two Year Warranty Warranty and Service