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Last modified 2021-03-10

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Johnson Messenger III (242-143 and 242-150)

A picture of Johnson Messenger III (242-143 and 242-150)

SPECIFICATIONS

GENERAL
Type:Citizen band transceiver
Frequency range:26.965-27.255 MHz
Channels/tuning steps:11 (Version 242-150)
12 (Version 242-143)
Mode:AM
Frequency control:Two XTALs per channel
Frequency stability:0.005% @ -30 to +60C (-22 to +140F)
Power supply:13.8 VDC
Current drain/power consumption:RX: 200 mA (Squelched)
TX: 700 mA
Antenna impedance/connector:50 ohm / SO-239
Dimensions (W*H*D):? mm (6.19*2.19*8.75")
Weight:? Kg (5 lb)
Other features:PA.




RECEIVER SECTION
Receiver system:Double conversion superheterodyne
1st IF: 4.3 MHz
2nd IF: 455 KHz
Sensitivity:0.5 uV (8 dB S/N)
Selectivity:6 KHz (-6 dB)
30 KHz (-60 dB)
Image rejection:
AF output power/speaker:3 W at 10% distortion / 3.2 ohm
External speaker connector:3.5 mm




TRANSMITTER SECTION
RF output power:~3.5 W (5 W input)
Modulation system:High level, class B
Max FM deviation:No FM
Spurious emissions:Less than -? dB
Microphone impedance/connector:1 Kohm / Fixed cord
Microphone input sensitivity:? mV




MISCELLANEOUS
Manufactured:USA, 1964-1970 (Discontinued)
Main PCB:
Additional info: Approximately 113000 units were manufactured
New price 1964 in the US: $189.95
Related documents: Service manual (29 MB)
Sams Photofact #: CB-8 (August 1965)
CB-30 (October 1970), version 242-143
Modifications and fixes:
Reviews:
Options/Accessories:
250-822
250-823
250-825
250-826
250-828
250-829
250-849
250-861
External PA speaker
AC power supply
Portable pack with one battery
Extra rechargeable NiCd battery
1.22 m (4 ft) fiberglass antenna
30.5 cm (12") fiberglass antenna
Antenna meter
"Tone alert" selcall unit