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Racal MA 4224 unit

 

Hello guys,

I get an almost new Racal MA 4224 encryption unit. They seem that our Army bought them before 1982. They are new. I think they don't used them.

My question should be: Would I be able to connect this unit to any radio?
Does it need power from the radio that pass through the TCVR connector?

Thanks in advance for your help.

Best regards to all,
Patricio
 

p10butty wrote:
Hello guys,

I get an almost new Racal MA 4224 encryption unit. They seem that our Army bought them before 1982. They are new. I think they don't used them.

My question should be: Would I be able to connect this unit to any radio?
If the audio levels are similar to those from a Racal radio, then yes.
Does it need power from the radio that pass through the TCVR connector?

Yes. Where else could it come from?

But you are going to need two ( or more ) of course. You can check pairs of them by connecting one to each audio socket and using the Intercom setting on those Racal radios that have it. But in the majority of countries it is illegal to use these on the amateur frequencies. They were quite popular with Alaskan fishermen and some folk in Central America which may explain the stupid prices they sometimes fetch.

It is an interestingly designed unit; despite the millions of possible settings of the internal links etc., a unit I have that had been used by the Iraqi army Republican Guard had strange modifications inside, presumably because they were worried that the manufacturer might have done something sneaky that would make it easier to decrypt. Pure paranoia.

And make sure the Nicad battery has not leaked and damaged the circuit board.

Dan

ac6ao / g3ncr
 

Dan wrote:

..>It is an interestingly designed unit; despite the millions of possible
..>settings of the internal links etc., a unit I have that had been used by
..>the Iraqi army Republican Guard had strange modifications inside,
..>presumably because they were worried that the manufacturer might have
..>done something sneaky that would make it easier to decrypt.
..>Pure paranoia.

But wasn't that exactly what happened during the first Iraq war?
It is widely believed that Racal co-operated with the British army to
decrypt Iraqi transmissions made with the Jaguar radio system that Racal
sold them.

Andy G8JAC
 

Thank you Dan for your information.
"make sure the Nicad battery has not leaked and damaged the circuit board."
Sorry I don't follow. This unit have a batery inside?
My Thomson TRC 310 have two pins with 15 V Pos and the other with 15 V Neg. Would this work?

I know that almost all British radios uses a 300 OHms audio accesories. When you refer to audio levels is because of this?

This unit is for the PRM-4031 family of radios?

Pin B should be power in?

Thanks a lot

Best regards,
Patricio

Lic. Patricio Diez Butty


--- El lun 2-ago-10, Dan Rae ±ð²õ³¦°ù¾±²ú¾±¨®:


De: Dan Rae
Asunto: Re: [Racal-manpacks] Racal MA 4224 unit
Para: Racal-manpacks@...
Fecha: lunes, 2 de agosto de 2010, 10:57

?

p10butty wrote:
> Hello guys,
>
> I get an almost new Racal MA 4224 encryption unit. They seem that our Army bought them before 1982. They are new. I think they don't used them.
>
> My question should be: Would I be able to connect this unit to any radio?
>
If the audio levels are similar to those from a Racal radio, then yes.
> Does it need power from the radio that pass through the TCVR connector?
>
>
Yes. Where else could it come from?

But you are going to need two ( or more ) of course. You can check
pairs of them by connecting one to each audio socket and using the
Intercom setting on those Racal radios that have it. But in the
majority of countries it is illegal to use these on the amateur
frequencies. They were quite popular with Alaskan fishermen and some
folk in Central America which may explain the stupid prices they
sometimes fetch.

It is an interestingly designed unit; despite the millions of possible
settings of the internal links etc., a unit I have that had been used by
the Iraqi army Republican Guard had strange modifications inside,
presumably because they were worried that the manufacturer might have
done something sneaky that would make it easier to decrypt. Pure paranoia.

And make sure the Nicad battery has not leaked and damaged the circuit
board.

Dan

ac6ao / g3ncr


?
 

Andy Jackson G8JAC wrote:
Dan wrote:

..>It is an interestingly designed unit; despite the millions of possible
..>settings of the internal links etc., a unit I have that had been used by
..>the Iraqi army Republican Guard had strange modifications inside,
..>presumably because they were worried that the manufacturer might have
..>done something sneaky that would make it easier to decrypt.
..>Pure paranoia.

But wasn't that exactly what happened during the first Iraq war?
It is widely believed that Racal co-operated with the British army to
decrypt Iraqi transmissions made with the Jaguar radio system that Racal
sold them.

Andy G8JAC

Andy, I've no idea. Just because you are paranoid doesn't mean they aren't listening :^) However I would think that a frequency hopping radio is slightly easier to crack than the system used by the 4224, but perhaps not, I'm absolutely not an expert. In the case of this 4224 someone had gone to a lot of trouble, including fitting a new eprom, and some board re-wiring with some extra circuitry. Not the usual level of 'skilled' work seen inside their 'surplus' equipment that I have seen, which is of the order of fitting a nail instead of a fuse, and replacing a capacitor by placing a big blob of solder over both wires.

Dan



Dan
 

Patricio Diez Butty wrote:


Thank you Dan for your information.
"make sure the Nicad battery has not leaked and damaged the circuit board."
Sorry I don't follow. This unit have a batery inside?
It has a Nicad battery to back up the settings. It is an epoxy encapsulated thing, yellow with white printed label, about 3 x 5 cm, visible on one of the boards when you remove the case. It has two or three button cells in it and can be replicated easily enough with NiMH cells and then will not leak in the future.
My Thomson TRC 310 have two pins with 15 V Pos and the other with 15 V Neg. Would this work?
I have used these with both 12V and 24 V Racals, so presumably 15 V is fine.

I know that almost all British radios uses a 300 OHms audio accesories. When you refer to audio levels is because of this?

This unit is for the PRM-4031 family of radios?
It matches those in appearance yes. I have used it with both the TRA931 and 967. Fishermen use it with presumably standard marine VHF radios, Narco trafficantes, I have no idea, but they can also be used with telephones and fax machines.

Pin B should be power in?

Patricio, I am pretty sure the manual is available for download somewhere on line, have you searched for it? In any case the plug wiring is the standard Racal audio one, but I don't have my books to hand.

Dan
Michael Buckley
 

Dan

That was very much what a contact I have who used to work for Racal rather thought of thir technical expertise.

They were said to have purchased channelled radios so they did not know what frequencies they were using as they could not "manage" them!

Mike B

On 02/08/2010 16:00, Dan Rae wrote:


Andy Jackson G8JAC wrote:
> Dan wrote:
>
> ..>It is an interestingly designed unit; despite the millions of possible
> ..>settings of the internal links etc., a unit I have that had been
used by
> ..>the Iraqi army Republican Guard had strange modifications inside,
> ..>presumably because they were worried that the manufacturer might have
> ..>done something sneaky that would make it easier to decrypt.
> ..>Pure paranoia.
>
> But wasn't that exactly what happened during the first Iraq war?
> It is widely believed that Racal co-operated with the British army to
> decrypt Iraqi transmissions made with the Jaguar radio system that Racal
> sold them.
>
> Andy G8JAC
>
>

Andy, I've no idea. Just because you are paranoid doesn't mean they
aren't listening :^) However I would think that a frequency hopping
radio is slightly easier to crack than the system used by the 4224, but
perhaps not, I'm absolutely not an expert. In the case of this 4224
someone had gone to a lot of trouble, including fitting a new eprom,
and some board re-wiring with some extra circuitry. Not the usual level
of 'skilled' work seen inside their 'surplus' equipment that I have
seen, which is of the order of fitting a nail instead of a fuse, and
replacing a capacitor by placing a big blob of solder over both wires.

Dan

Dan
 

Thank you again Dan. Yes I see the cell you mean now.
I will change it.
I search the net but I couldn't find the manual for this unit.

Best regards,
Patricio

Lic. Patricio Diez Butty

--- El lun 2-ago-10, Dan Rae ±ð²õ³¦°ù¾±²ú¾±¨®:


De: Dan Rae
Asunto: Re: [Racal-manpacks] Racal MA 4224 unit
Para: Racal-manpacks@...
Fecha: lunes, 2 de agosto de 2010, 12:14

?

Patricio Diez Butty wrote:
>
>
> Thank you Dan for your information.
> "make sure the Nicad battery has not leaked and damaged the circuit
> board."
> Sorry I don't follow. This unit have a batery inside?
>
It has a Nicad battery to back up the settings. It is an epoxy
encapsulated thing, yellow with white printed label, about 3 x 5 cm,
visible on one of the boards when you remove the case. It has two or
three button cells in it and can be replicated easily enough with NiMH
cells and then will not leak in the future.
> My Thomson TRC 310 have two pins with 15 V Pos and the other with 15 V
> Neg. Would this work?
>
I have used these with both 12V and 24 V Racals, so presumably 15 V is
fine.
>
> I know that almost all British radios uses a 300 OHms audio
> accesories. When you refer to audio levels is because of this?
>
> This unit is for the PRM-4031 family of radios?
>
It matches those in appearance yes. I have used it with both the TRA931
and 967. Fishermen use it with presumably standard marine VHF radios,
Narco trafficantes, I have no idea, but they can also be used with
telephones and fax machines.
>
> Pin B should be power in?
>
>
Patricio, I am pretty sure the manual is available for download
somewhere on line, have you searched for it? In any case the plug
wiring is the standard Racal audio one, but I don't have my books to
hand.

Dan


?
 

Thank you Dan for the battery cell info. I take it away from the unit.
Wich voltage does it have?

Best regards,
Patricio

Lic. Patricio Diez Butty

--- El lun 2-ago-10, Dan Rae ±ð²õ³¦°ù¾±²ú¾±¨®:


De: Dan Rae
Asunto: Re: [Racal-manpacks] Racal MA 4224 unit
Para: Racal-manpacks@...
Fecha: lunes, 2 de agosto de 2010, 12:14

?

Patricio Diez Butty wrote:
>
>
> Thank you Dan for your information.
> "make sure the Nicad battery has not leaked and damaged the circuit
> board."
> Sorry I don't follow. This unit have a batery inside?
>
It has a Nicad battery to back up the settings. It is an epoxy
encapsulated thing, yellow with white printed label, about 3 x 5 cm,
visible on one of the boards when you remove the case. It has two or
three button cells in it and can be replicated easily enough with NiMH
cells and then will not leak in the future.
> My Thomson TRC 310 have two pins with 15 V Pos and the other with 15 V
> Neg. Would this work?
>
I have used these with both 12V and 24 V Racals, so presumably 15 V is
fine.
>
> I know that almost all British radios uses a 300 OHms audio
> accesories. When you refer to audio levels is because of this?
>
> This unit is for the PRM-4031 family of radios?
>
It matches those in appearance yes. I have used it with both the TRA931
and 967. Fishermen use it with presumably standard marine VHF radios,
Narco trafficantes, I have no idea, but they can also be used with
telephones and fax machines.
>
> Pin B should be power in?
>
>
Patricio, I am pretty sure the manual is available for download
somewhere on line, have you searched for it? In any case the plug
wiring is the standard Racal audio one, but I don't have my books to
hand.

Dan


?
 

Patricio Diez Butty wrote:


Thank you Dan for the battery cell info. I take it away from the unit.
Wich voltage does it have?

Best regards,
Patricio
3 cells Patricio, so 3.6 Volts nominally. I made replacements from 3 x 100 mAH NiMH button cells potted in epoxy similar to the originals. I even copied the original label.

Google does show some sources for the manual in pdf form, but you may have to pay for it :^) Search for "MA4224 manual"

Dan
 

Hello,
I am over this item again. Now I have two MA-4224. I take the internal battery from one of them. I still have to make new cells.

I make special cables in order to connect the encryption unit to my TRC 300 radio. One cable to adapt the original socket from the radio to a US U-229 connector (with 6 contacts), and another to connect the MA-4224 to a US U-229 also with 6 contacts. The cables were arrange like this:

TRC 300 PRC-25 Racal
Mike: A----------D----------A
PTT: B----------C----------C
GND: C----------A----------D
SPK: D----------B----------F
+12V: F----------E----------B
-12V: H----------F----------E

Check pic here:

I saw that the Racal radios have B por power in and use the GND or D pin por -12V. I connected neg. to pin E because the TRC have in a separate pin. I don't know if that is correct.

I try the unit with the radio and when the unit MA in in off, I received and transmit ok. But when I switch to 1/2/3 or load I can't.

Am I missing something?

Please I need help. I wasn't able to find the manual.

Thank you in advance.
Pat
lw8dbp

--- In Racal-manpacks@..., Dan Rae <danrae@...> wrote:

Patricio Diez Butty wrote:


Thank you Dan for the battery cell info. I take it away from the unit.
Wich voltage does it have?

Best regards,
Patricio
3 cells Patricio, so 3.6 Volts nominally. I made replacements from 3 x
100 mAH NiMH button cells potted in epoxy similar to the originals. I
even copied the original label.

Google does show some sources for the manual in pdf form, but you may
have to pay for it :^) Search for "MA4224 manual"

Dan

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