HS7- 42, Special Operations Executive Signals History, Introduction.
In de Spring of 1943 a new C.S.O. (The present Director of Signals) was appointed, Base Stations and Schools placed under their respective Commanders, who in turn were directly responsible to the C.S.O. London HQ. This closer contact provided a more homely atmosphere, inspired confidence, and instilled a deeper sense of responsibility throughout the Signals organisation.

Operations benefited by this arrangement as their planning had the close co-operation and advice on Signals matters of the C.S.O. himself. A department was also provided at the London HQ which was responsible for all messages collection and distribution. This was linked with the operational stations by means of private telephone lines and teleprinter circuits. Started in 1942 with one teleprinter link, it developed until late 1943/early 1944, 15 teleprinter circuits were working. This arrangement enabled Signals to keep the Country Sections informed of the communication situation on request.

In June 1943, forward planning was done regarding the erection of a third station near Poundon. This station to be erected, equipped and staffed by the American counterpart of SOE, but under the direction of the C.S.O. Signals, London HQ. This station was to ease the ever-increasing pressure on the existing stations, and cover Special Forces and Jedburgh operations planned for the invasion of Normandy. (See Jedburgh History).

Work on this station was started in September 1943, and by January 1944 was completed with a total of 36 channels.


The stations and training schools were given symbols and will in future be referred to in this way:

GRENDON   -  Station 53A
POUNDON 1 - Station 53B
POUNDON 2 - Station 53C

Training school Thame Park  -  STS 52
Training School Fawley Court - STS 54


In September 1943 a Director of Signals was appointed with full control of all Signal Stations at home and abroad.
(See D/Sigs Charter and Plans 612/1850). Appendix A will illustrate the complete signals network then under his control.

The organisation of the Signals Directorate at home and overseas prior to D-Day can best be illustrated by the table of organisation shown overleaf.

Appendix B and C show clandestine Stations in position. North West Europe beased on stations 53A, 53B and 53C.

Appendix D illustrates Jedburgh teams operating in France from D-Day plus 4, until November 1944.

Appendix BD superimposed on Appendix B shown Jedburgh progress (in date order) during the campaign, and Clandestine Stations formerly in position, linked up with, or replaced by Jedburgh Teams dropped to support the advancing armies.


The volume of traffic by this time had increased beyond expectations. This borne out by the fact that soon after the first station was opened the approximate total traffic handled was 15-20.000 groups (
1 groep bestaat uit 5 morse tekens) per week with one station working. By the Spring of 1944 this had increased to approximately 500.000 groups per week with three stations working.

In October 1944, the American Station 53C having fulfilled its purpose, OSS withdrew its support. Their remaining commitments - SF Unitis taken over by 53A (
Grendon-Underwood), Norwegian circuits by 53B (Poundon1).

Forward planning now revised for the immediate invasion of Norway, and arrangements made to cover this from SOE Signals point of view. A tremendous amount of work was necessary to realign aerials at 53A (
Grendon) from being directional for France to being directional for Norway and the Low Countries. The latter to cover SF Units which had, by this time, moved forward to the German frontier.

In December 1944, certain economies were asked for and it was decided to move station 53A (
Grendon) to the American site (Poundon 2, 53C), amalgamate training at Grendon, and close down Thame Park and Fawley Court. These moves were completed by the en of the year. In addition, all Norwegian circuits were transferred to 53A (Grendon) as it was considered that the aerials at 53A were better suited for the work than those at 53B (Poundon1).

With the collapse of enemy forces in France, traffic had become easier, but the possibility of a Norwegian invasion and the fact that upwards to 160 clandestine stations were in position in Norway, the traffic figures again rose sharply.

In March 1945, SOE were approached to provide signal cover for the airborne relief of POW camps in Germany and possibly Austria. (See CMoVG 7780 6-3-1945, CD/7807 10-3-1945, File:  Safe 32). This new commitment required much revision of planning, technique and distribution of station load, and in order to relieve 53B (
Poundon1) to carry the POW commitment, all Dutch plans were transferred to 53A (Grendon). Staffing problems were again experienced. To relieve this pressure, 50 ATS operators were brought in. These operators were only partially trained and not conversant with SOE procedures. Intensive training was necessary both for ATS and POW team operators.

In order to protect the personal security of these special teams who were going to drop into Germany itself, a new technique was introduced. Provision was made for the despatching of 120 teams each supplied with its signal equipment.
To enable them to establish contact quickly, it was arranged that the Base Station would send its call signal continuously on frequencies considered suitable for the dropping zones. This provided the Outstation with a "marker" or "tuning" note, so that, if the Base Station was heard, the Outstation was able to use one of the frequencies supplied to it which was allied to the Home Station "marker" frequency, and contact established without delay. This provided more freedom of movement for the Outstation which did not have to adhere to a rigid timetable for passing information. (See Signal Planning).

Time was also saved on coding, as it was decided that the whole operation should be so mobile that messages could be 'flashed" in "clear" (
zonder codering in klare taal).

In April 1945, the final plan for the Norwegian campaign was approved. It was agreed that this might have to be done in three stages, and separate plans were drawn up to meet the following emergencies:

a. In the event of the enemy making a last stand in Norway A full scale opposed landing.
    (see DSG/687 and MUS2213/2523)

b. In the event of German capitulation the surrender should be made to the Norwegian Resistance leaders.

c. In the event of capitulation and German refusal to surrender to the Resistance leaders to render all assistance
    necessary.

To cover these demands an intricate signal network was made ready to be swung into position should any of the emergencies outlined in a, b or c arise.


In May 1945, the German capitulation was complete, including enemy forces in Norway. Consequently a much modified signal plan was adopted to cover Special Forces Units which took up positions in that country unopposed. These in time took over the load formerly handled by the clandestine network, and this, combined with the fact that Norway's internal communications were left intact, led to the quick falling of the Norwegian traffic. It was, however, agreed that during the Grendonfirst few, indeed, vital days, the only satisfactory channels of communication between the Army Commander and Norway was over the SOE signals network. Also for some time, SOE acted as a clearing house for all intelligence passing to and from the field, making known to the Army Commander and the Resistance leaders in turn their respective wishes as to administration and policy.

In June 1945, the traffic handled was very light. By this time the POW camps had been relieved by the swift advancing allied armies. Consequently only a very few teams remained on this commitment.

Further economies were demanded. The remaining 53B (
Poundon1) commitment was handed over to 53A (Grendon), training moved from Grendon to 53A so that operations and training could be housed under one roof. Training was revised as the only requirements to be met were trained personnel to allow for "wastage" abroad.

In August 1945, Japan capitulated and in early September it was decided to cease training.

Operations are still active although now reduced to a minimum. Vital links only being kept open to Norway, Denmark, Holland, Belgium, Czechoslovakia, Italy and Germany.


Grendon-Underwood: receivers at Grendon Hall, transmitters at Charndon.
Poundon-1: receivers at Poundon, transmitters at Godington.
Poundon-2: Receivers at Poundon (Hill), transmitters at Twyford                     
© Nick Fox



TRAINING
.

In 1941 a small SOE wireless training unit was formed at Grendon to train wireless agents for the field. These agents, when trained, were placed under the control of SIS. The number of agents under instruction was very small, usually in the order of about 18 to 20 in all. These agents were obtained from a pool of refugees (see file 1/120/29 - Archives).
Recruits with previous knowledge of signalling were in demand. Good use was made of WT operators ex-maritime services. Those with a previous knowledge of signalling were given a short course, in all about six weeks. During this period they were expected to gain a thorough knowledge of SOE signal procedure, understand how to service their equipment, encode and decode messages, to physical and small arms training and be fully conversant with the intricacies of unarm combat. Those with no previous knowledge of radio were kept in training until they were considered fully trained for their duties.

By June 1942, the average number of agents continuously under training had increased to between 30 and 40. Training was revised to meet operational commitments, now r completely by SOE. The course was lengthened to 16 weeks. This gave students a little longer time to reach a higher standard of proficiency. Not only were they trained as WT operators, but their personal wellbeing was also considered. They were given intensive training on how to conduct themselves in an enemy occupied country. Exercises were arranged under the most realistic conditions, agents were taught to "live the part", pass intelligence to the training school by radio and act "action messages" received from the school's control station. Organisers worked with them and Field Security Police acted the part of Gestapo. The output in June 1942 was approximately 6 to 8 fully trained agents per month.

An amusing incident which occurred when two trainees were on exercise in Newcastle can be recalled. It was arranged that on a particular day, one of them would to to the market place, "spot" his organiser and follow him to a secret rendezvous without attracting the attention of the ver watchful "bogus" Gestapo. The other trainee had the morning off, happened to be in the same part of the city with nothing much to do and, observing that a "Following exercise" was in progress, decided to join in. A CID man who had nothing to do with SOE, observed the second man behaving in a most peculiar manner and decided to 'trail" him to find out what was afoot. He became more puzzled than ever when the chase led him out of the city, and decided to arrest his man for further questioning. The trainee refused to disclose his identity, and was only released when confirmation had been received from the School Commander, through the local Security Office, as to his identity.

In late 1942 the demand for trainees had exceeded the supplies available from the refuge pool. Service channels were contacted with a view to recruiting British officers with good language qualifications. recruits were fairly plentiful with a high standaard of intelligence. This was most helpful as the subjects could be gone into more deeply without prolonging the course. The output was also increased to 12 - 14 fully trained agents per month. This output was maintained throughout the period of hostilities. In late 1943, early 1944, the figure rose to as high as 16 - 18 per month. This was mainly due to the fact that security training was (about this time) treated as a separate subject, consequently signals dealt with Signal training only. One of the most important features of training mixed nationalities was the language difficulty. Most of the schools engaged on SOE work were set up for independent nationals. Signals only had one school, and upwards of eight different nationalities were in training simultaneously. The language problem was so acute that the only way to overcome this difficulty was to have translations made of all the lectures, into the various languages concerned. All lectures were also translated into French, Dutch and Norwegian, these being the languages most commonly used. Agents had to be divided into classes so that they understood at least one common language, and were also supplied with copies of a particular lecture or lectures in their own language. In this way, they were able to follow the instructors more closely and discourse amongst themselves on points on which they were not particular clear. This methode not only enabled them to understand more fully the problem of radio, but also fostered a spirit of comradeship throughout their period of training. (Some achievement with mixed nationalities). This could not have been done unless establishments had allowed for one instructor per two students. Also it was not infrequent that at the conclusion of training operators were sometimes kept waiting for several weeks before final departure in the field. Refresher courses had to be improvised and special post-graduate exercises arranged.

In June 1942 personnel for Base Station work were in short supply and it was necessary to provide training for this emergency. FANY's were introduced and WT training started at Thame Park. The result was over-crowding. It was decided to move the FANY trainees to Chicheley (STS 46), and a second signal school for Base Station personnel was started. By September 1942 this work was growing so rapidly that the whole of Fawley Court (STS 54) was set aside for FANY training. Numbers increased by "leaps and bounds" and by late 1943 there were approximately 100 - 150 FANY's (WT operators, teleprinter operators, control clerks, traffic clerks and drivers), continuously under instruction. In addition, instructors worked hard in London to produce the necessary number of "coders" enquired. It was anticipated that upwards of 200 - 250 coders would be required. This figure was later found to be a fairly accurate assessment when all stations plus the Headquarters section were working to full capacity.

In autumn of 1942 SOE were asked to co-operate in Exercise "Spartan", organised by GHQ Home Forces and believed to be the forerunner of the invasion plan proper, (See Appendix F). This gave SOE Signals an opportunity of testing the signal arrangements which they planned specially for the exercise. A Base Station was established at Dunbar which would pick up information from special Jedburgh and "Boykin" teams infiltrated behind the enemy lines, and relay this information to Special Forces units attached to the various army formations. The type of equipment plus the "snappy" signalling method used in SOE carried the day, so much so, that information passed through the SOE network was received and distributed much quicker than any other service involved. Agents and FANY's considered only partially trained were used, but they were so keen on the job and had been so well briefed, that they made few, if indeed any, serious mistakes.

The plan than to establish Base Stations in England to provide radio cover for the invasion forces was accepted as a result of this very fine exercise. Agents and Jedburgh parties dropped behind the enemy lines as well as SOE/SF units accompanying army formations were to send back to the respective Base Stations all intelligence. This in turn, to be passed to London HQ for collection and necessary action. In November 1943 therefore, training of WT operators for Jedburgh parties proper was started at STS 54 (
Fawley Court). At first the numbers were small with only a total of about 18 French O.R. (other ranks).

By January 1944 the total strength had increased to some 135 OR's. They were all quartered at Peterborough and worked daily contact with Dunbar and STS 54. They were given continuous practice in opening communication quickly. the majority became so well versed in this "drill" that they responded automatically. In addition to the OR's  who were to be employed as WT operators, there were some 300 officers (British, US, and French, in about equal numbers) who were undergoing training for special duties. They too, were given instruction on opening up and maintaining communications and eventually were able to do so, although of course, at a much slower speed. When D-Day arrived, the Jedburghs gave account of themselves (See Jedburgh History).

In all, between 90 - 100 teams were dropped into France alone. The work of SF Signals who underwent similar training will be described later under the heading of "Special Force Communication".

It is interesting to note that the bulk of personnel trained as WT operators had no "flair" for this work, or indeed, had ever considered becoming such. The success with which they performed their duties in the field is an excellent example of what men and women can achieve under the drive of patriotism, and of course, to the care and patience of their instructors.



SIGNAL PLANNING.

Signal Planning was in itself highly specialised, as without a carefully prepared signal plan, wireless contact would not have been possible.

Consideration had to be given to:

a. Nature of operations.
b. WT security of the Outstation.
c. Geographical location of Outstation.
d. Channel capacity of Base Station.
e. Frequencies available.

These points in turn governed the personnel security of the WT operator which of course, was of paramount importance, and gave protection against possible interception by enemy intercept services which would lead to his position being located by enemy DF (Direction Finding) systems. In North West Europe the DF network was extensive.

Made sure that the Base Station concerned could at all times be able to make quick contact with an Outstation or Outstations at any given time.

Allow all SOE stations to work within the frequency band allocated to the SOE signal network.

Enable frequency allocation to be made for any given distance according to the geographical position of the Outstations.

Asses the type of equipment to be carried for ant particular type of operation.

In 1942 a very simple type of plan was used. The callsigns and time at which contact was to be made were fixed and remained constant. In fact, the whole framework was so rigid that it was quite easy for the enemy interceptor to find out when a station was due to come "on the air", pass this information quickly to the DF section who plotted the particular clandestine stations concerned. Casualties were heavy and the signal planning in consequence revised.(HS7-33)

In August 1943, the "V" Plan (Variable Plan) was produced. Its purpose was to endow the communication arrangements with greater signal security. Call signs and contact times were flexible and did not repeat over a period of one month. The plan made the task of the enemy interceptor direction finder much more difficult, and clandestine stations worked with more confidence. The inevitable however, happened, signal plans wee captured, and in time considered "blown". Production was discontinued and signal planning further revised.(HS7-33).

In March 1944, the "X" Plan superceded the "V" Plan and was, to some extent, an improvement. The difference being, that whereas in the "V" Plan the contact times were fixed in strict date sequence, either consecutively or on alternate days, the "X" Plan was designed to allow for contacts to be made at pre-arranged times but on irregular dates. This plan worked well, but it was thought that the "X" Plan might in time be collated by the interceptor as it did not entirely break away from the "V" Plan. (HS7-33)

In August 1944, the "Z" Plan was developed, This provided an arrangement whereby the callsigns, contact times and dates on which contact was to be made, did not repeat over a period of four months. In addition, the Base Station, call sign (which on all other types of plans had remained constant) now changed in step with the Outstation's changing call sign. An arrangement to allow emergency contacts to be made was also laid down in conjunction with the "Z" Plan. This combination was considered to be capable of giving the Outstations a high standard of wireless security. (HS7-33)

Conditions of dropping into Germany itself were considered extremely difficult, any attempt to produce a signal plan which had and semblance of rigidity would have led to heavy casualties. To guard against this a new technique was developed. This was known as the "Marker" channel system.

The Base Station transmitted continuously a series of call signs on pre-arranged frequencies and listened simultaneously on frequencies which it was anticipated the Outstation would be heard These continuous call signs on given frequencies acted as a guide to the Outstation as to which frequency to select n order to establish quick contact. Immediately a call sign was heard, the Base Station answered on another pre-arranged frequency at the same time maintaining the calling system throughout. This meant that the Outstations could establish contact at will, pass traffic and close down quickly, thus giving them complete wireless security as it would be practically impossible for the enemy interceptor to collate any data received.

Signal planning in a much simplified form was arranged for para-military operations. The reason being, that a high degree of wireless security was not considered a major necessity.

Each groep of plans , (8 plans in a group) were allotted to a channel. All worked on a frequency common to the group. The Base Station maintaining a permanent listening watch on given frequencies.  Each Outstation was also allotted an indicator letter which formed part of the call sign and proved a means of identification for each particular Outstation. In this manner, contact could be established at any time without having to adhere to a fixed time table. (HS7-33)



BROADCASTING.

Establishing contact during the hours of darkness had always been extremely difficult for various reasons, small power used by field stations, frequencies employed and interference caused by on these frequencies. Therefore signals from the field were unsatisfactory, but since it was possible to build transmitters of much higher power at Base Station it was decided to use the time which was unfavourable to field transmitters to send messages on a Broadcast system from Base Stations only.

Early 1943 a system of Broadcasting was introduced (not to be confused with the BBC). This was a new technique whereby messages were transmitted in morse code, on medium power, by the broadcasting methode. This methode had several advantages:

a. Making use of the hours of darkness. Thus extending signalling time to 24 hours per day.

b. Enable the Outstation to receive during prohibited hours, defeat the DF system which would work in step with curfew
    regulations, and was always on the alert for illicit transmissions during the night.

Special broadcast planning had to be provided. For this purpose, Outstations were divided into groups (4 stations to a group). All stations in each group had the same recognition signal in order that it could identify the Base Station coupled with it.

Following the reception signal, an indicator (or advise signal) was transmitted stating that a message was to follow, or that there was no message for a particular Outstation on that date. This enabled stations to continue listening or close down, as the case may be. Messages were transmitted in the order in which they were indicated. Each group was allowed a three hourly broadcast period. To confuse the enemy interceptors, and prevent them from being able to detect to which particular area an abnormal flow of traffic was being directed, the recognition, indicator signals and frequencies used were changed completely, either at three monthly or four monthly intervals.



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11-06-2019