John Brown became interested in aircraft and flying so, when war was declared it seemed natural for him to apply to join the Royal Air Force. But his wireless firm was classed as carrying out essential work so he was held there in a reserved occupation. Eventually he was called up but to the Royal Signals where the powers that be considered (probably correctly) his skills to be more appropriate. At Catterick he was made an instructor and then one day was told he was being transferred to the War Office. In July 1941 he reported to 55 Broadway to be interviewed by the then Sqn Ldr Frank Pile, instructed about matters of security and, as a second lieutenant, given a travel warrant to ‘a place called The Frythe’. His wartime career was thenceforth almost exclusively in the Wireless Section, later to be called the Radio Communications Division.
On his arrival in July 1941 the major expansion of Station IX had not taken place but even so Brown immediately got the impression that what was going on there seemed like way-out science fiction. On the drive was what appeared to be a searchlight. Over dinner with a Maj Schroter, who sported a patch over one eye and was known locally as ‘dead-eye Dick’, he was told it was a device to beam supersonic sound across no-man’s land to drive the enemy mad! Maj Schroter might have known what the device was but it is most unlikely that his explanation to the young second lieutenant was anything but imaginative fiction.
Brown was put to work with a Capt Rickard, given a large, standard-issue Civil Service briefcase complete with the embossed letters ‘OHMS’ and told to build in it a radio with a range of several hundred miles. He could make full use of the workshop which occupied the conservatory of the mansion. This workshop was staffed by around half a dozen instrument makers and precision tool makers who could work very quickly to a high standard from the most basic of sketches. What was as important was that they were able, and indeed encouraged, to provide their own feedback and ideas about problems they encountered or could foresee. A sketch left with this team on the way to lunch was sometimes turned into hardware and waiting by the time Brown had finished his meal.
One task he was presented with was to see if an ordinary superhet broadcast receiver could be used as a transmitter. He designed a plug-in box which allowed the set to transmit morse code on crystal-controlled short wave frequencies. In September 1941 he was asked to make six of these sets which were called ‘L-sets’. He worked on various other projects for people including R.J. Cook of the former D-Section who was dealing with scrambling, coding and remote radio-controlled devices and Capt Bert Lane, whose work on the airborne part of the ‘S’-phone was furthered by the use of a Wellington bomber at De Havilland’s nearby Hatfield airfield.
From the end of September 1941 many more people arrived at Station IX and it became a 24-hour operation. It was normal to work a 16-hour day, seven days a week. Along with many others, Brown slept in the comfort of the mansion. The increasing tempo of the war was reflected in the urgency attached to everything and the positive response it received. In October, when the numbers of laboratory staff alone had risen to twenty-five, they responded rapidly and produced twelve complete radio sets suitably installed in cases for hurried delivery to the Middle East.
In the late spring of 1942 Brown was asked how quickly could he make a transceiver for communicating with the continent of Europe: it was required in days rather than weeks. This was the period when SOE gained its independence from SIS and work on its own wireless sets could start in earnest. His idea was to adapt a type HE army back-pack set with a range of only a few miles. He had the help of supply liaison officers such as Capt Ward who, brandishing the appropriate piece of official paper, scoured the country to requisition anything needed for this vital work. Brown had only to ask and it would appear very quickly. In August 1942 after a week of hectic work the wireless set was rebuilt to operate on limited frequencies from mains or dry batteries with a range of up to 400 miles and was designated the Type A Mk 1.
The Type A Mk II Suitcase Wireless Set
SOE saw the need for agents to carry their wireless sets, sometimes in great haste, by hand or on bicycles without attracting attention. It therefore conceived the idea of the suitcase set, a wireless transceiver built specifically to fit in an ordinary-looking continental suitcase. The suitcases were produced and ‘aged’ by Col Wills’s Camouflage Section at Station XV, but the ‘works’ were made at Station IX. The first of these was the Type A Mk I whose valves proved fragile and which was quickly improved as the Mk II. The set comprised three metal boxes each measuring 11 in × 4 in × 3 in, with space at the end for storage of the headset, morse key, spares, etc. The left-hand box contained the receiver, the middle one the transmitter and the right-hand box contained the power pack which provided the choice of either an external 100– 240 volt mains supply or a 6 volt car battery. The set operated in two wave bands; 3– 4.5 megacycles and 6– 9 megacycles, had a power output of 5 watts and the whole case weighed 20 lb (9 kg). Just one prototype was produced before Marconi came to assess it for production in November 1941. Inevitably, there was then a demand for a more powerful set, the Type B, with a range of 1,500 miles and a wider frequency selection. The urgency attached to this project secured the sole use of four of F.J. ‘Freddie’ Moore’s technicians who, according to the history of the section written at the end of the war, ‘performed yeoman service’. After a colleague had designed and added a power-pack and it had been fitted into a suitcase, made by the Camouflage Section and suitably aged by being used as a football in the courtyard, it was sent to Pye at Cambridge for production. The drawing office then had to convert the freehand sketches upon which the prototype had been built, into production drawings. The Type B, which had twice the power and versatility of the Type A, had been made in less than a month and by the end of January 1942 three complete Type B Mk I sets had come off the production line. The Type B was later used in the capture of a German general in Crete and in Operation Gunnerside which destroyed the Norwegian heavy water plant and denied Hitler atomic power. The sets also saw service in Singapore and Yugoslavia.
By now 100 of the ‘S’-phone ground sets had been produced but the airborne part of the system was proving more problematical. It was also around this time that the laboratory designed and developed an instrument known as the Telephone Interceptor Unit for tapping telephone lines without having to cut them. Their ingenuity extended to a cleverly coded, microwave-operated relay which was successfully demonstrated but did not attract any interest. Their minds were then set the task of devising a vibrator-operated unit for an HT supply to replace the dry battery power for the ‘S’-phone, which had proved impractical. Following this Brown was given a free hand to design a smaller Type A Mk II. He made just one prototype before Marconi came to assess it for production in May 1942.
The Wireless Section continued to expand and in January 1942 had a total strength of sixty under the now promoted Lt Col Pickard. It was clearly time for some serious attention to be given to its organisation and it was decided to form four sections: Headquarters, the Radio Research and Development Laboratory, a Supplies Section and a Production Unit. The Radio Research and Development Laboratory was led by Professor A.H. Wilson FRS, a Cambridge mathematics don later to become a director of Courtaulds, and had separate specialists dealing with short-wave apparatus, microwave equipment, laboratory instruments, a model shop, and there were also staff for field trials. The Production Unit was staffed by twenty-five people who were not at this stage required to produce more than small batches of equipment.
The Type B Mk II Suitcase Wireless Set (B2)
Because of the great urgency attached to its design, the Type B Mk I had been a large and heavy collection of various standard components. Now came a demand for the Mk II – a lighter, more robust set. This one was designed completely from scratch and all components were made in the workshops. Col Tommy Davies, known in Baker Street as one of SOE’s ‘hard men’, had set a deadline and to meet it the team worked non-stop for 36 hours, finishing it at the end of Febru
ary 1942. Such was the urgency for this set that Brown worked through the night of 4 March testing it with people standing by to give any help needed. A Lt Myshrall had a car to rush two sets to a port in the West Country where a ship waited to take them to Cairo. As it happened, the ship became delayed in Malta and when the island’s wireless telegraphy station was put out of action by enemy bombing, the powerful Type B Mk IIs were used as a temporary replacement. Technically this was the 3 Mk II but it was usually known as the ‘B2’ and with the Type A Mk II was the most popular wireless set for SOE’s operators in the field from 1943 onwards. It incorporated a feature whereby at the throw of a single switch power could be transferred from the mains to an in-built, 6-volt battery. This was ideal for thwarting Gestapo searchers as they switched off the power to buildings and listened for the transmissions they were monitoring to stop, thus narrowing their search. Such was the importance of the work that it was only after Brown had seen the sets despatched that he was told his wife had given birth to a baby girl and he was granted leave to go and see them both. Soon he was back at The Frythe to work on the instruction books which were essential to any piece of service equipment and to look into the design of a hand generator and a pedal-powered generator for charging the accumulators which powered the wireless sets.
The adaptors for converting a normal receiver into a transmitter were developed further until the Converted Broadcast Receiver was produced. This was a normal domestic continental-pattern wireless set which had been made to serve as a short-wave transmitter. On the face of it, such a set had a great future with SOE in occupied territories but nothing more was heard of the concept. More successful was the miniature broadcast receiver designed by a Norwegian Air Force officer, Lt (later Capt) W. Simonsen. One of these was carried by Maj Everett, who was able to receive the BBC World Service in India and Ceylon. Easy to conceal, this was intended to permit the nationals of occupied countries to listen to the morale-boosting broadcasts and coded messages of the BBC.
In the early summer of 1942 the Wireless Section’s strength had risen to sixty-seven, their accommodation being in hastily erected army huts among the trees and rhododendrons of the grounds around The Frythe. More space was urgently needed, as indeed it was for other sections at Station IX. So available factory space was sought and eventually in mid-June the Production Unit moved to the Bontex Knitting Mills on the North Circular Road near Wembley. The Headquarters and Supplies Sections followed a month later and this establishment became known as Station VIIa. The Section seems to have chosen this time to change its title to Radio Communications Division.
The thirty laboratory staff remaining at Station IX were directed by Prof Wilson who was assisted by Dr N.L. Yates-Fish, a physicist, serving as a consultant. A number of small specialist groups evolved to cover short-wave equipment, microwave equipment for aircraft, microwave equipment for ground use, field and air trials, laboratory and test instruments, photographic records and publications, and technical liaison. Then there were the Drawing Office, Model Shop and Stores. Each group comprised on average three persons, two of whom were experts in their fields.
The feedback from agents in the field called for a much smaller and lighter set which could be delivered in a parachute container more easily, carried around with less effort and, most importantly, could be more readily concealed. America had produced the miniature Loctel valves which Brown now incorporated into his draft design, which was passed over to Marconi and became the standard Type A Mk III set. Ill-informed comparisons by Operational Sections between the Type A Mk II and the Type B Mk I sets sparked controversy. What they did not realise was that the requirements to which the designer had to work were different for each set. Brown had fulfilled the requirements, so criticism of RCD was somewhat unfair. It might have been this episode which resulted in Pye of Cambridge being asked in August 1942 to develop Brown’s Type A Mk III into a smaller and lighter set than its predecessor but without any loss in performance. In the event the development was a success.
The Type A Mark III Suitcase Wireless Set
This development was smaller and lighter than the B2 and was considered by some to be one of the best sets for SOE’s use, being not only the smallest transceiver produced in the Second World War but a product of extremely good miniaturised design and workmanship. It was contained within a small suitcase measuring only 13 in × 9 in × 4 in and an accessories box, the whole set weighing only 9 lb (4 kg). It covered 3.2– 9.0 megacycles in two wavebands and produced an output of 5 watts which limited its reliable range to 500 miles.
Under the intense wartime pressures agents sometimes encountered differences of opinion with laboratory staff when they asked for totally impractical features to be incorporated into their sets. Operational Sections came to be regarded as ‘absolutely impractical’ while the technical staff of RCD were looked upon by them as ‘amateurs’. In many ways the entire set-up of Station IX was amateurish. A collection of sharp brains had been plucked from their normal peacetime occupations and set to work on problems in areas which many had never before entered. Such were the demands of SOE that it would have been foolhardy to place research and development contracts with established professional firms of experts, even if they possessed the capacity to indulge in the kind of unconventional activities engaged upon at Station IX.
As it was, a Liaison Group within RCD exchanged ideas with other organisations such as the Telecommunications Research Establishment, the Royal Aircraft Establishment Radio Section, the Signals Radio Development Establishment, Admiralty Signals and with manufacturers of radar equipment.
Brown had the occasional break from the problems of wirelesses, including some electrical work on the Welman one-man submarine, some test runs on the Welbike and some Sten gun firing on the range. At about this time in February 1943 there is evidence but no details of another interesting development, for an order was placed with Creed and Co. Ltd of Telegraph House, Croydon for the production of twenty-four ‘semi-automatic morse transmitters’. What these were and whether they had any connection with the high-speed or ‘squirt’ morse transmission apparatus is not known.2
In 1943 the Chief Signals Officer in charge of SOE communications, Brig Nicholls, Royal Signals, who had succeeded Ozanne, visited Station IX and held a meeting in the ante-room where, over drinks on his account, he outlined the need for a successor to the Type B Mk II. And he needed thousands of them. The wireless had to be small, light, robust, capable of operating on any mains voltage – AC or DC – and, above all, it was, of course, very urgent.
In April 1943 concern was expressed at the lack of wireless sets. While the supply of ‘A’ sets was adequate, there was a chronic shortage of ‘B’ sets. It was decided that none should go to CCO unless the specific operation for which it was needed was important enough to justify the diversion.
TABLE 2
April
May
June
July
Demand for ‘B’ sets
163
163
99
100
Estimated delivery
100
150
50
100
The Miniature Communications Receiver, MCR1
The leader of the laboratory, Prof A.H. Wilson, received a Laboratory Development Order dated 11 April 1943 for the development of a Miniature Communications Receiver Mk I to the specification agreed. Brown was given the job and moved out of Hut 4 into another with two assistants who had been relieved of all other duties. Capt Ward, the supply liaison officer, was briefed to get anything the team needed. The job had super-priority. Ideas were soon developed into a prototype, all the time considering that this had to be a set suitable for mass production. The packaging of the set was to be a readily disguisable tin. The Philco company at Perivale in north-west London, under the brothers Marcel and Pierre Vaufrouarde, were awarded a contract for 10,000 sets. Brown spent the summer of 1943 sorting out production design problems
until in August pilot production started with Sgt Maj Fred Stallworthy, Royal Artillery, taking over liaison work with the manufacturers.
The Miniature Communications Receiver Mk I or MCR1 was, as its name implied, both small and only a receiver. It weighed only 2 lb and was sent out in a Huntley & Palmer’s biscuit tin measuring 8½ in × 2 in × 3½ in. Le recepteur biscuit, as the French named the set, was soon being produced at the rate of 500 per week and was later to be used in the Far East where the ability to seal the container proved essential in the high humidity.
High Speed Morse Transmissions – ‘Squirt’ transmissions
On 5 May 1943 the Communications Committee (Technical) had explained to it by someone whose name was not recorded, the principle of the ‘squirt’ transmitter. This has to be viewed in the light of the great danger agents’ wireless operators were exposed to during their periods of transmission. German direction-finding equipment was being improved all the time and the only counter-measures available to operators were to alternate between several wireless sets in different locations and to keep transmissions as short as practical. Around fifteen minutes was considered acceptable; twenty minutes and the risk of detection was increasing rapidly. The ‘squirt’, or high-speed morse transmitter, was a means of compressing the normal fifteen-minute message into a period of only a few seconds, thereby denying the Germans the time to locate the source. A week after the meeting, Laboratory Development Order No. 140 instructed Mr W.A. Beatty, the deputy to Mr G.A. Willis, who had succeeded Prof Wilson when the latter joined Tube Alloys to work on the atomic bomb, to ‘build equipment for a high-speed morse transmitter’. The other part of the problem, the receiver, was to be explored in parallel as a high-speed morse recording system. Beatty left ISRB towards the end of the year and the work passed to his chief assistant, Mr D.J. Spooner. Eric Slater, recruited to ISRB in 1943 from REME to work in the operational research and test groups under Maj Brown, confirms that a device was indeed completed and was capable of transmitting short messages. It was described as a rod on which were a number of brass and insulating cylindrical spacers. By adjusting the length of a brass piece (for example one piece for a morse ‘dot’ and two for a ‘dash’) and by doubling the insulators between morse letters, one could simulate a simple message. Some means had to be devised of making this arrangement provide electrical impulses through a transmitter. As a result of a successful trial of a ‘squirt’ transmitter between Scotland and Station 54 (a Signals Station at Fawley Court, Henley-on-Thames), which was about the same distance as from central France to the SOE receiving station at Grendon near Bicester, it was decided by the Communications Committee (Technical) to order 500 sets of agents’ ‘squirt’ equipment. But sadly this was premature for the equipment was too bulky and a technique for receiving and de-coding the highspeed signals had not been perfected. The development order was eventually cancelled on 20 April 1944. Despite claims in some published works, SOE never issued this intriguing invention to the field except, that is, as a known non-functioning device with the turned German agent Kick in the curious case of Operation Periwig (see Chapter 15).3
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