Modern Era FM Backpack Portables

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      A 53
   B 56






    B 56

is a modular mobile radio set from South Africa.
The most important parts of the radio set are:

SO-55 is the main unit
(transceiver part)
The main unit SO/55 can be removed from the system and, using the provided accessories, can be used as a portable radio.

A-55 is the main unit SO-55
plus battery pack
This system is operated by an internal dry battery or a rechargeable NiCad- battery. An external 12V- DC- PSU can provide power to the radio using an audio connector.
Circuits for remote operation and rebroadcast operation are built in.

SO-56 is the chassis and the HF amplifier
The broadband HF- amplifier is driven by the SO/55 output of 2W, and provides a maximum of 25 W HF power. It also can be used as HF amplifier for different radios of the same frequency band.
A built in measuring instrument monitors the operation of the other units in the system.
The amplifier is protected against overload, short circuit and open lines.

B-56 is the main unit SO-55 plus
chassis HF amplifier SO-56
B-56 is mounted on the shock absorbing mounting
The complete B-56- system is monted in a vehicle using this mounting by quick connect padlocks. It has four rubber shock absorbers.

AIU-56 is the ATU for the mobile
radio system.
The ATU is installed close to the antenna, usually in the roof of the vehicle. It tunes rod antennas and 50 Ohm antennas over the complete working frequency.
An automatic network allows the close by use of several systems at the same time. This happens for example at rebroadcast operation or while using several systems in one vehicle.

Pictures are missing for:

  • AB/55/56 remote control unit and
  • KB/56/1 DC power supply.

    Thank you, Brad, for providing some of the pictures!

    Frequency range:
    26 ... 75.975 MHz


    Technical data:
    Frequency control:
    Channel spacing:
    25 kHz
    Channel storage :
    10 , stored in a special module.
    This module may be exchanged to a frequency-hopping- module.
    HF output:
    Manpack: 1.5 W
    Mobile: 2 ... 25 W
    Power consumption:
    Mobile 1.5 ... 15 A
    Manpack Battery / cells last:
    7 .. 12 hours
    Antenna tuning:
    Manpack powered by:
    Dry battery
    NiCad- battery
    external 12 V
    Tone- Squelch ( 150 Hz ) or
    Voice- Squelch are built in