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)
3
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
c i rcuitry and an automatic noise limiter. The receiver also features increased
p rotection 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
21LTDST.MANUAL.REV.QX 9/25/98 10:59 AM Page 5
