BRUIN SYSTEM

The bulk of the BRUIN information is provided by Roger Greenaway

The BRUIN tactical trunk communications system revolved around Communication Centres servicing Comheads. The Comcens were interconnected, so it was possible to communicate from brigade HQ all the way back to Corps HQ, and even back to the UK.

Brigade Level

Each brigade HQ had two Comheads, namely Main and Step-up. One was fixed on the ground, while the other was on the move. There were, in the early 1970s, six manouver brigades in Germany with an independent artillery brigade, with an additional three infantry brigades when 3 (Airportable) Division was deployed from the UK for BAOR reinforcement.

Division Level

There were three  mechanised divisions in Germany, with, as already noted, 3 Division in the UK. 3 Division was BRUIN-compatible. Each division had three Comheads (Main, Step-up and Rear), and maintained 2 Comcens (except for 3 Div, which only had one). The Comcens were designated alphabetically, being:
1 Division (Verden) : Charlie & Delta
2 Division (Bunde) : Echo & Foxtrot
4 Division (Herford) : Golf & Hotel
3 Division (Bulford) : Whisky

Corps Level

1 (BR) Corps (HQ in Bielefeld) had four Comcens, namely Alpha and Bravo servicing Corps Main and Step-up HQs (run by 7 Signal Regiment, Herford), and Uniform (Corps Rear HQ) and Victor (Radio) run by 22 Signal Regiment (Lippstadt). Comcen Uniform also serviced detachments at WHAs (Weapon Holding Area) and WSPs (Weapon Supply Point), ie the tactical nuclear capability.

Others

There was a Comcen (part of 21 Signal Regiment) that supported RAF Germany, and specifically the helicopter and Harrier forces in the field. Comcen Kilo (16 Signal Regiment, Krefeld) supplied links (cable and static radio relay) back to the UK. Detachments could be deployed from division Comcens to flanking foreign brigades, these being Canadian (Lahr), Dutch (Seedorf) and Belgian (Soest, later Cologne).

Occasionally links were established into USAREUR units (mainly V Corps) and the Bundeswehr. Detachments, consisting of a radio-relay vehicle and a terminal equipment vehicle, were deployed as these foreign units were not BRUIN-compatible. Signal Group (Territorial Army) was not BRUIN-compatible. The group supplied a line of communication from BAOR back to the Channel ports and airports, and linked into Comcen Kilo.

BRUIN - EQUIPMENT

The BRUIN system was based on a 6-channel PCM radio-relay network. Channels 1-4 were routed through an automatic telephone exchange, channel 5 was “manual intercept” and channel 6 multi-channel telegraph.

The Crypto equipment was the BID200 (Dakota), feeding into either a C50/R236 or C70 radio-relay detachment.

Station, Radio C50/R236

Referred to simply as the C50, it comprised a radio transmitter (C50), receiver (R236), RF Amplifier (RFA13 with its associated PSU49 & PSU50), a frequency synthesiser set Plessey PG341, and the line equalizer into the BID200 system (BID 200/10). Frequency range was 225-400 Mhz with 125 KHz channel separation. Output was 10W ERP with 50W and 200W on medium power and high power settings when the RFA13 was used. The antenna , known as a “fishbone”, was a log-periodic (logarithmically-spaced series of transposed dipoles), fitted as pairs in a single frame in slant polarisation. Beamwidth was around about 35 degrees with a high front-to-back ratio. The station could be used dismounted (training purposes and Op. Northern Shot), mounted in a 1 ton container fitted on a Bedford RL truck, or in a trailer (3 Division only). They were also fitted into FV439 APCs at brigade level.

Station, Radio C70

Basically this is a Siemens FM12/800, with a different E11 module from the German version.  This set had a frequency range of 560-910 MHz, again with 125KHz channel separation. The antenna was spherical (basically a spiral embedded into a fibreglass tube). Two were mounted on the mast and could be connected together, but there had to be greater separation between transmit and receive frequencies. These were mounted in 1 ton containers on a Bedford truck chassis, and used at division and corps level.

Deployment:

Brigade signal squadrons had 2 complete sets of vehicles. Each set consisted of 3x FV439. These versions of the FV432 APC series had 2x 3.½KVA generators in an armoured bin on top of the vehicle. The three versions were Auto20, MCVF and radio-relay. The Auto20 had a 20-line Strowger-type automatic telephone exchange, MCVF the crypto gear (BID200), manual telephone exchange and teleprinter (Siemens T100R). The radio-relay version, as well as having a 40ft pneumatic mast fitted, had 2 banks of C50/R236. 3 Division brigades did not have any trunk capabilities, these were held centrally at the division signal regiment.

The divisional signal regiments were divided up into squadrons, whereby 1 Squadron had the Comcens, Comheads and radio-relay detachments.ie in 1 Division, 1 Squadron had Charlie  and Delta Troops . Charlie TP had the equipment for Comcen Charlie, and Comhead for Division step-up and rear HQ as well as a link to 11 Mechanised Brigade, whereas Delta Tp had the same for Comcen Delta and the Comhead for Division Main HQ , as well as a link to 7 Armoured Brigade .

The main equipment were message centres in 4 ton containers, Auto40 exchanges (also in 4 ton containers), and C50 RR detachments for links to brigade, and C70 for links to Division HQs and Corps Comcens. A single C50 detachment with three banks of equipment was held in each troop as a relay vehicle.

The main radio-relay vehicle was the Bedford RL. This had a pallet holding a mast, spare mast (plus a third for relays/double-anchors), an antenna stowage cage (C50 only), 2 3.1/2KVA generators (plus 4 fuel cans), a 1 ton container with either 2 or 3 banks of equipment. Dingo (the relay vehicle for Delta Tp), when loaded out as per SOP7 (including weapons, ammunition, fuel, rations, personal kit and 3-man crew) weighed in at 13.½ tons! (the vehicle had an MLC of 9).

At corps level there was a 180-line automatic telephone exchange (a second was held at the School of Signals for training and Corps technical reserve) in a 4 ton container. There was also a TARIF container (Telegraph Automatic Routing In the Field). A second unit was held at the trade training regiment (8 Signal Regiment), also held as Corps technical reserve.

3 Division, being then an airportable unit, had it’s equipment in airmobile 1 ton containers (Aircon B), which could be towed to the airfield or mounted in pairs on a Bedford flatbed. The radio relay detachments (C50) consisted of 2 Land Rovers and 2 trailers. One Land Rover carried 2 generators and towed the antenna trailer with 2 40ft masts and 2 sets of antennae. The other Land Rover carried personal kit (sometimes a bank of C50), and towed an equipment trailer (known as a fish-fryer) with 2 banks of C50.
 

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This is a Bedford RL radio relay truck with a spare generator. (Photo courtesy Panzenbaer)
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C50 air portable radio equipment in use. (Photo by Roger Greenaway)
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C50 radio antenna on a Clark mast.(Photo by Roger Greenaway)
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C70 radio antenna. (Photo credit unknown) 

 
bruin_1div_s.jpg This is a schematic of 1 Division deployment. The Brigade step-ups are shown as broken lines. One was on the ground while the other was on the move. Once established, they changed around. Click to enlarge (Drawn by Roger Greenaway) 
Bruin equipment was used outside of the Bruin system to supply secure communications in at least two and possibly more operations These are now declassified.
 
1) Operation Purple Stilts
 
This was deployed in the event of London flooding but is now redundant as a result of the completion of the Thames Tiver Barrier. Unit involved was 3 (Airportable) Division HQ & Signal Regiment (based in Bulford). A Comcen was not deployed, It was  a straight comhead-to-comhead link.

Comhead 1- RAF Northwood/HMS Warrior (now renamed). This was a NATO HQ with a "hole in the ground" (three storey nuclear bunker). BID200 (Dakota) assembled underground with a quad cable going up the ventilation shaft. The cable, installed in 1971, is still there. C50/R236 detachment in the carpark nearby (backing on to the Admiral's rose garden!)

Comhead 2- Ministry of Defence building, Whitehall. C50   dismounted and installed with the BID200 in an upper storey. The antenna was mounted on the roof.
Relay  - A relay station was set up outside Whipsade Zoo.
The exercise to practice this operation was known as EX Old Bailey.
 
2) Operation Northern Shot
 
This was a system set up in Northern Ireland to provide a secure link from HQNI (and PUSNI) to mainland UK. Since there is now peace in the region,  the system was deinstalled.

Comhead 1- Set up in a rented farmhouse outside Stranraer (Scotland), link from there to London via secure landline. (End user was Northern Ireland  Office)
 
Comhead 2- Radio-relay terminal at 233 Signal Squadron (NI), 2 sets for the Stranraer link, One for Stormont; one back-up and one in the workshop  (as a maintenance base). The BID200 was in the Signal Centre at HQNI. Antennae were on the roof of the HQNI building.
 
Comhead 3- Initially run 24/7, later as required.  Two sets (one running; one back-up). Was collocated with BID200 co-located. Set up in the attic at Stormont Castle (Office of the Permanent Undersecretary-of-State), The antenna was on the roof.
 
Relay   - Divis Mountain relay/rebro site (outside Belfast). two banks towards Lisburn, plus two banks with RFA13 towards Scotland. The antennae were freestanding on 40 ft pneumatic masts.

 
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A technician who worked on the BRUIN system has provided this recollection.  "I worked on the set up of Bruin briefly before moving back to EW. There were two types of radios used. The first  was the Plessey C50/R236 combination. It operated in the frequency range 225-400 MHz for TDM and FDM operation. RF output is either 10,50, or 250 watts. The station superseded Station Radio C41/R222. The C50 transmitter, as I recall, had its own separate power supply as did the receiver. A tuning turret and synthesizer were fitted and the six transmit crystals in the tuning turret were all we needed to tune up the transmitter and receiver. These were supplied initially in Bedford 3 ton trucks.

An integral part of the C50/R236 setup was two synthesizers, one for RX one for TX. These were flat oblong boxes on top of the C50 with one on top of the other. On the front of each synthesizer was a panel which had  five or six knobs. Each knob was calibrated in MHz. The frequency one wished to work was set up on each of the synthesizers. The line equipment, One plus Four Number Three which I mentioned, was connected to the communications center with a quad cable, just as we had done with the previous Larkspur C41/R222 combination. The communications centre was comprised of four, Bedford 3 ton trucks. Fitted in those trucks were various teleprinters, a cryptography kit, which at that time would have been a BID kit and the telephone exchange. In some armoured units, the radio and line equipment would have been mounted in FV439s, which were the signals version of the FV432 APC then on issue.

VEHICLE BODY

The box body was on the rear and in the middle between the radio body and the cab were two "ONAN" generators of US manufacture. Each could be slid out on its respective side. These were of American manufacture and were electrically started with just one switch! LUXURY! Imagine how good this was after having used the Coventry Climax generators which you had to hand crank and were mounted in a trailer which meant hard work in  placing and camouflaging it. Each vehicle had a Clark mast mounted by the cab which was raised and lowered hydraulically. A spare was carried in the radio box body.

Another set used with Bruin was the Siemens C70. This was, I recall, a UHF set and difficult  to tune.  This was fitted  in an Austin K9 radio vehicle, again with Clark masts, but had the old Coventry Climax towed generator".

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C-50 transmitter of the C50/R236 combo. (Photo courtesy Wireless for the Warrior)
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R236 receiver of the C50/R236 combo. (Photo courtesy Wireless for the Warrior)
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C-70 radio relay set. It was used in Division and Corps areas. The frequency  range was 610 to 960 MHz using FDM or TDM operation. RF output is 10W. This gave the relay station a range of approximately 25 miles. The set is a modified version of the Siemens FM 12/800 system. (Photo courtesy Wireless for the Warrior)
 


Credits and References:

1) http://www2.armynet.mod.uk/museums/royalsignals/postalcovers/baor.htm
2) Wireless for the Warrior  http://www.wftw.nl/receivers/r236.jpg
3) Wireless for the Warrior  http://wftw.nl/larkspur/c50.jpg
4) Wireless for the Warrior  http://wftw.nl/larkspur/c70.jpg
5) Roger Greenaway <schliesser92(at)gmx.co.uk>
 
 

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Feb 15/16