Cobra Electronics 21 LTD operating instructions Specifications, Channel, MHz

21LTDST.MANUAL.REV.QX 9/25/98 10:59 AM Page 5

Specifications

FREQUENCY RANGE

The COBRA21 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 COBRA21 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.

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	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		5 3/4” W x 1 3/4” H x 7 1/2” D .
Weight		1.2 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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