Racal MA 4230A Morse Encoder & MA 4231A Morse Decoder

Brooke Clarke 2012

Racal MA 4230 Morse
          Encoder & MA 4231 Morse Decoder
Background
Description
    Photos
    Connectors
    DC Power
Related
Links

Background

The MA 4230 Morse Encoder is very similar in function to the GRA-71 & GRA-71 PRC316 in that they both can record a message and then send it at a high speed using the Morse code.  The MA 4231 is a decoder that can be used in the field unlike the GRA-71 which was a field to base one way communications system.  I expect the MA 4231 can receive messages generated by the GRA-71.

The units on this web page are the Aribic versions (hence the A suffix on the model number).

Note that neither of the Racal boxes has a message display.  In that sense the FS-5000 Spy Radio is nicer in that it has a message display on the controller.  There are other components to this system including the MA-4232 Battery Charter, MA 4233 Printer and the MA 4235 complete sytem.  I'm guessing that the reason for the lack of a message display is so that a box can be inserted between these boxes and the printer for encryptiion and decryption of the messages.

These units have a non field replaceable rechargeable battery which means when that battery goes dead the units become obsolete, hence these what appear to be new units on the surplus market.

Description

Photos

Connectors

Racal MA 4230A Morse Encoder & MA 4231A Morse
                  Decoder Connectors

Front mounted Core Series D style Fischer
The two connectors on the MA 4230 are receptacles with type Z reversed polarity (i.e. pins instead of sockets).
The other type of connector is a receptacle with normal A polarity (i.e. with sockets).

Fisher, 5-pin female plug: S103 Z054-130+
Fisher, 5-pin male plug: S103 A054-130+
Cable clamp (largest cable size 6.7mm): E3 102.616.7
Fisher contact us

DC Power

The 4 hex head screws that hold the box together are 2.5 mm.
To separate the two halfs remove the screw on the bottom in case there's a vacuum and they use a flat blade (-) screwdriver to pry open.

MA 4231 Racal Morse Decoder Inside
MA 4231 Racal Morse Decoder 400
                DK Battery
Marked Varta 400 DK
Possible p/n:
6140-01-336-7123
and/or
RCL-932005

Measures 0 Volts.
Red wire to + end.
Battery made up of 5 each 400 DK cells hence the 5/400 DK reference
to connect the cells a cap is spot welded to the negative face and it's
flange is slipped over the + end of the adjacet cell then the flange is spot welded.
A lower resistance method than using tabs.

At 1.2 Volts/cell this is a 6.0 Volt rechargable battery.


It's strange that the top is tapped for 6 screws but only the 4 corners of the bottom are used for the 2.5mm hex head screws.

Related

GRA-71
GRA-71 PRC316
FS-5000 Spy Radio
Cryptography
Crypto Machines
Cryptography Patents
PSG9 PSG-9 Message Terminal (Computer)
Telegraphy

Links

Crypto Museum - Racal MA 42xx components

PRC68, Products for Sale, Alphanumeric Index of these web pages

This web page created 25 Dec 2012