Chapter Three

On to Cowes - and the Decca Era

We now return to the very early fifties to study more closely the growth and development of the Decca Radar group. This had been sharing premises with Decca Navigator in Burlington Road, near Shannon Corner, a busy junction on the Malden Way section of the Kingston-by-pass. (Refer to the map - Fig. 4). Equipment designed and developed here was manufactured at the Company's "Malden Way" factory on the other side of the by-pass. During this decade the Decca Radar Company was to grow from small beginnings to a high plateau of success with AR-1.

This was a time of rapid growth in the Civil Aircraft industry, but the expansion of services that the jet engine was making possible was limited by the lack of suitable aids for aircraft navigation and control. This was the challenge that the electronics industry was called upon to meet.

But electronics technology was still in the era of the thermionic valve which set some limit to the bandwidth at which a radar could operate, whereas the requirement was for radar having wide bandwidths.

By 1953 it was already clear that the Decca Navigator was a world beater. This equipment, carried in the pilot's cabin, kept him in continuous alignment with ground stations. But on the ground, and particularly in the neighbourhood of airports the increasing number and speed of civil as well as military air traffic was straining the capability of air traffic control. This situation had been correctly analysed by the Radar Group's market research branch and organisational changes were made to meet the expected demand.

The Radar Group had developed naturally into two sections and the rapid growth of both Navigator and Radar activities caused the accomodation at Burlington Road to become overcrowded. The Marine Section (under Mr. Maurice Easy) moved to premises behind Tolworth Broadway, further along the by-pass and the Radar Research and Development laboratories (under Mr. S. R. Tanner) to the Tolworth roundabout in the old Fox and Nicholls factory. (Fox and Nicholls had been well known in prewar days as makers of racing cars which were tested on the then virtually deserted by-pass). The research labs were fortunate in finding premises suitable for use with only little adaptation.

The research and development laboratories were now engaged on several important contracts, including a military air defence system (codenamed 'Richard' ), some equipment for mine-laying detection along the coast ('ADA') and a system for use in submarines ('AA').

Systems test was housed, in what was locally referred to as the 'copper room' and the aerial test site was near Maidenhead (later moved to Holton Heath near Wareham in Dorset). As time passed project 'ADA' (which was a 45 r. p. m. radar) was run down because the need for this type of system had lost its urgency and in fact only two were ever built.

Fig 4

There were also the river and harbour radars : one example of the former went to the Rhine, one of the latter to Calshot, for the Southamption Harbour Board. Some of these early valve productions have lasted twenty years or more, indeed the one at Calshot was only replaced as recently as 1972.

Naturally valves made the wide-band radar systems difficult to build. However, the problems were overcome with admirable precision. Airport Surface Movement Equipment (ASME) was developed and installed at London Airport, becoming the first equipment of its type ever to go into actual use.

In 1953 work began on the project which was to be the first real development of the Heavy Radar Group as such. Mentioned above, its codename was 'Richard'. By 1954 another project called ' Simon' got underway, a system intended eventually to control radar over telephone wires. The Heavy Radar Group by now was beginning to establish itself.

Project 'Richard' was the experimental model of a radar which went into production under the name 'Victor'. Project Leader was Mr. R. L . Burr, work involved engineering an experimental system under contract to THE (Telecommunications Research Establishment). Meanwhile 'Simon' had proved a disappointment but 'Victor', now known as the 'Type 801 was looking a success. The radar employed a 1-Mw S-Band Magnetron and with its success the Heavy Radar Group was on its way.

The 'Type 801 is interesting from several points of view. It was probably the last radar whose design was still influenced, if not dictated, by the experiences of the last war. The aerial was large, the power units and transmitter were in proportion, and of course, it still employed valves. But germanium diodes and transistors were beginning to exhibit their qualities and improved devices for handling the massive peak power output of radar transmitters (magnetrons, klystrons etc. ) were becoming available.

It was natural, therefore, for the Company to use the experience gained on the 'Type 80' for other, particularly commercial, radars, and Mr. Burr, the engineer responsible for the 'Type 80' was put in charge of the newly formed Heavy Radar (Commercial) Group.

The development of the 'AA' equipment was going well, but cabinet shape had to be tailored to the contours of the submarine hull, and this led to a problem. Like all defence contracts 'AA' had a security classification, but the curtain was caused to lift slightly when a visitor from a foreign country, who was being shown the capacity and capability of the Research Laboratory facilities recognised the distinctive shape of the cabinet and deduced the purpose of the radar!

However, this incident did not seem to diminish his opinion of Decca' s radar expertise because a contract that was being negotiated with his government was soon afterwards confirmed.

Another early development was the '4241'. This comprised a mobile airfield control set which was to prove a remarkable success, with well over a hundred sets being produced and sold. It cannot really be grouped with the heavy radar because it was developed independently, nevertheless it later became part of the Heavy Group. The 424 was another achievement which typifies the capability of the Decca team of the day. The complete design, drawing board development of a working prototype, from scratch, was accomplished within two months.

Meanwhile Mr. Easy's Marine Radar Group had outgrown its premises behind Tolworth Broadway and had moved a little further along the by-pass to a trading estate at Davis Road, Chessington.

The Marine Radar Group had been pursuing a vigourous sales campaign to such effect that sometimes the dosing team had scarcely been assembled when the salesmen committed them to delivery dates. This practice had its dangers and was probably dictated by the need for revenue to finance development. However it served to establish Decca as world leaders in Marine Radar and even now, of all ships fitted with Radar fifty per cent have Decca equipment. What better tribute to the confidence and sheer ability of those electronics engineers of nearly a quarter of a century ago.

Soon the 'Type 80' became too big to be contained in the laboratories at Tolworth and between 1955-56 the Research Laboratories moved again. Thus the Heavy Radar Group followed Mr. Easy to Davis Road and it was here that the first HF200 became a reality.

The Research Laboratories had also been investigating the processes for simulating and displaying all the information that the new generation of radars were capable of producing. A new section, the Display and Data Group was formed at the "Toby Jug" offices and the Research and Development Functions were separated.

In June 1956 Mr. Easy assumed control of Radar Development, which in fact was what the Davis Road activities has become, and the Research Laboratories made another trip down the Kingston by-pass and along the Portsmouth Road to Horsham, near Esher.

The transistor had appeared in quantity as early as 1954 but only in the 'point contact' form. These were difficult to bias and self-destructed easily. The OC70 appeared by 1955 and experiments were soon begun with these. An interesting tale concerns the first use of OC70 by Decca personnel. They had built a receiver using the transistors and tried to use it to receive the home service, having successfully picked up the light programme. However, the gain of the transistor was not high enough and it was discovered that a simple crystal worked with greater effectiveness! With incredible speed however, the transistor came into its own. Decca designed the 'Gold Brick' - a very early transistor radio and by early 1956 the Heavy Radar Group had produced a receiver from PNP transistors. Indeed by late 1956 Dr. R. Scary and his group had produced the prototype of the first transistorised radar. The Heavy Radar Group had arrived.

The 424 was proving a tremendous seller and with small variations was sold under a number of names. These included:

Throughout the period several families of marine radar appeared and passed, continually keeping pace with technology, and other competitors. Of course it was essential to keep the price down as far as possible - it was not enough to sell radars to the large tankers and the like, a wider range of shipping was needed if sales were to be kept up.

In 1954 the initial heavy group, as such, had consisted of a Senior Electronics Engineer (Mr. J. Flounders) a Senior Mechanical Engineer and two draughtsmen. We have seen how the Heavy Group had expanded considerably throughout the period previously described. This expansion however was small by comparison with that which was to take place in the next few years. Many remarkable developments soon followed and one in particular was to become the basic building brick for the heavy radar both under Decca and, later, Plessey. 1957 saw the birth of the equipment as we know it today.

The first development was the MR75, a Medium Range air surveiliance radar having a maximum range of seventy-five miles. This was an 'X'-band equipment but because 'X'-band is weather sensitive the equipment was not an entire success, only six were produced, five going to Canada and the remaining one to Iceland. The design concept, however, was subsequently used for the development of Meteorological Radars carried out in the Decca Marine Group and the experience gained in producing this and the Type 80 was to prove invaluable.

The reader will recall that one of the faults with the original Chain Home stations was that aircraft could fly under the beam and go undetected. The second development of the Group was a Transmitter/Receiver (Tx/Rx) for use with low cover radar, intended for coast watching roles. The equipment itself was I S'-band, codenamed 'Lotus', later to be renamed LC150 Tx/Rx because of its subsequent use with the LC150 aerial. It was this 750kW Tx/Rx that was to continue in basically its original form throughout the period to date, becoming the basic building block for innumerable projects.

As the years have passed the Tx/Rx has become modified through the introduction and subsequent use of travelling wave tube amplifiers, parametric amplifiers, stabilised local oscillators, tunable magnetrons etc. Although somewhat improved it has survived the last two decades and it is a tribute to another early development that the same basic Tx/Rx is being built at Cowes today. Through valves to fully integrated solid- state equipment the original 'Lotus' has fulfilled, and indeed is still fulfilling numerous roles when linked with various aerial systems such as LC150, AR1, AWS1- 2, 43S, WF-44, DASR1 and AR15. The Heavy Radar Group was trying to exploit the commercial market rather than concentrate largely on government work and to this end the LC150 was designed for the Danish Navy, to whom six were sold, more were later sold to Indonesia, It is interesting to note that the original prototype was moved from Surrey and spent its last years at Cowes in the early sixties.

Recall that the original Type 80 project had become too big to be housed at Malden Way, and during development of the LC150 Tx/Rx the group moved from there to Davis Road, Chessington -under the same roof as the Marine Group. It now started to expand under Mr. R. L. Burr (reporting to Mr. Easy). Mr. Burr was formerly in charge of the Type 80 development. After completion of the LC150, work immediately started on 'Captain, a 2 1/2 MW Tx/Rx with the experience Decca had gained developing the Type 80.

Market research carried out while production of the Type 80 was progressing showed the need for a height finding radar and work on a suitable aerial system was begun at the Decca Hersham Laboratories, as a private venture. The result was the HF200, finished in 1957 and which has since proved a wonderful success. indeed up until 1972 the original HF200 design had remained virtually unchanged. An early prototype is still in use for demonstration at Cowes.

The 2 MW Tx/Rx developed at Davis Road was soon linked with the HF200 aerial, the set immediately gained the interest of the Air Ministry to whom quite a considerable number have been sold. There were now two Tx/Rx's - the 750kW (low power) and the 2 MW (high power). A fairly massive test programme was undertaken with the HF200 set by Decca - with the aim of getting a large Nato Air Defence Project. This contract consisted of a chain of high power reporting instrumentation between Norway and Turkey and was codenamed NATO HPRP (later Nato Air Defence Ground Environment - "NADGE"). Decca, however, eventually dropped out of the project and the HF200 was taken up by the British Government to replace the American FPS6. This led to several HF200' s becoming part of the "linesman" defence system and generally the HF200 began to sell very well indeed. In fact it was not until the Ministry had conducted its own evaluation of the HF200 that it placed its extremely valuable orders. When it was seen that the HF200 reached the critical standards of the Ministry other countries and private air transport companies became customers and the HF200 was well and truly launched.

It was evident that the 750kW Tx/Rx ('S' - band) was undoubtedly well ahead of its time Decca realised this and began to look for new avenues where this Tx/Rx could be utilised.

At this stage, we must be clear about ' government finance'. All government backing must be worked for - there is no 'easy money'. The Type 80 had been developed specifically for National Defence in this country and hence had no commercial market. It had been developed on a 'cost plus contract' basis; a reasonable arrangement for both parties. The advantage to Decca was that it was able to build up a team which retained the 'know how' which could be carried forward to future work. The early 'AA' and ADA' projects had also been government aided, but the HF200 was different : it was a private venture by the Decca Company and as such can be considered to have been a formidable financial risk to Decca. Naturally this was a calculated risk but the heavy initial financial drain with no returns in sight for at least two years must have been worrying. Again we must pay tribute to the courage of Sir Edward Lewis and Group Captain Fennessey.

We have now reached late 1958, the majority of work was still being carried out with valves but the effects of the transistor were beginning to be felt. The display systems had now become fully transistorised, naturally germanium because although silicon transistors had appeared they were extremely expensive. (More than 5 each.)

The Company now began to develop several new projects having formed an association with a French company who were to supply highly specialised aerial systems. The Company was called Societe Nouvelle Electronique (SNE -now part of the CFTH Company, France) and the aerial system was to form the basis of an air surveillance radar, the first Decca Air Surveillance Radar, named the DASR- 1. This had a back-to-back aerial using the 750kW Tx/Rx that had already proved so successful. (Figure 5).

Beam (1) gave the high cover while beam (2) was a long-range low-cover aerial. The beams were arranged in this manner because the long-range low- cover beam gave a considerable amount of ground clutter at short range. The high beam was so arranged that in the short ranges it provided the cover while minimising the effect of permanent echoes. In all, nine DASR- 1's were built and sold, going to all parts of the world. The first DASR-1 went to Llandebr in Wales where it went into service with the Air Force. Here rockets were being tested by firing them into Cardigan Bay, several radar stations were set up around the Cardigan Bay coast in order that the rockets could be tracked and any shipping in the area could be located and warned. The rocket range itself was stationed at Aberporth, a further radar site was erected in the north at Rhiw. All the radars supplied to this testing ground were manufactured by Decca and one of those which followed the DASR1 to Wales was to become the forerunner of the widest selling Air Surveillance Radar yet produced.

Meanwhile another development was resulting from the association with SNE, this was HYDRA. Hydra again had back to back aerials but each aerial had two horns, providing four beams in all. The principle was the same as that for the DASR- 1 but, referring to Figure 6 we see gaps in between the beam coverage, beams 2 and 4 were intended to fill in the gaps and provide a fuller coverage. (Figure 7(a)).

With the two beam arrangement it is physically very difficult to get good crossover. Hydra accepted the gap but provided two more beams to fill it in.

It was clumsy to an extent but it gave more or less complete coverage. For the four beams there were two transmitters and four receivers.

(Figure 7 (b))

Displays from back to back aerials were awkward looking - they gave a 'cartwheel' effect. (Referring to Figure 7(c) the display sequency is obtained by following the numbers). Large contracts for Hydra included, "Teacher/Proctor", "teacher" being the codename for the type which used the 2- MW Tx/Rx and "proctor" for the Hydra which used the type 80 Mark III Tx/Rx.

Meanwhile the Danish Navy, expressing great satisfaction with their LC 150' s, put in an order for a shipborne radar. Work began on this immediately eventually culminating in the most famous of all Decca Radars, the AR 1. This radar used a completely new aerial system and in its original shipborne state went under the title of AWS1. Four of these were supplied to the Danish Navy. Another large contract of the time was the supply to Indonesia of a complete defence system, codenamed 'Parrot'. Equipment was valued at 4 million but to Decca, with installation etc, the total contract was worth more than 10 million. This contract, gained without any competition, included HF200's, two hydras, several LC 1501 s and two DASR- 1' s. Installation was completed just as the Indonesian Governement changed hands - Decca never got the equipment working and consequently this task passed into other hands.

Fig 5 Fig 6 Fig 7a Fig 7b Fig 7c

The Group had, by now, expanded further at Davis Road, taking in a nearby building formerly used by a paint company. The building was gutted and refurbished to include a model shop, wiring bay, test area, drawing office and laboratories. From the original four the group had now reached over eighty.

By late 1959 the opportunity had arisen for Decca to set up a small site at Cowes on the Isle of Wight. In 1960 a number of personnel moved here to escape from the "hurdy- gurdy" of contract life in Chessington and concentrate on design and development of new systems using advanced techniques.

On a general note it is obviously necessary to have laboratories as near to the production area as possible. Unfortunately in Surrey the laboratories were at Davis Road while all production took place at Malden Way, several miles down the road. The Heavy Radar Group was becoming too big to be contained at Davis Road and, furthermore, the initial move of the people to the Isle of Wight was linked with a wish for the group to further expand - either here or elsewhere. Expansion in Surrey was vetoed by the Board of Trade,and concern was being expressed by London Airport over interference to their Air Traffic Control System, caused by the testing of high power radar systems. Several areas for expansion were offered to Decca by the Board of Trade, mainly because of the unemployment situation in these areas.

These were :

The Isle of Wight was selected as being the most suitable and the Company acquired the site of the one time Cowes Airport at Somerton. Grounds were very extensive with plenty of room for expansion. Buildings at the time consisted of the two old hangars (which remained from the airport days and which, incidentally, still carry "Cowes Airport" on their side t ) and two new but very small wood and brick constructions. The latter two are now used as Post Design Services (P.D. S. ) and the Training School. They are shown as A and B respectively on the site diagram (Figure 8). Originally they contained the laboratories (now P.D.S. ),wiring bay, Workshop, and a production engineer, the training school, drawing office and a small wet-and-dry print room (now the training school only). There was plenty of room for expansion and development and with the closure of the local shipyards imminent, unemployment would soon be very high for the area. In 1960 a small production unit was set up in the two hangars (known locally as the "black sheds") producing primarily HF200 aerials while work on the buildings as we know them today proceeded.

During this very early part of the last decade, while the buildings were still incomplete a most remarkable development was made which was to lead to the tremendous success of the AR-1. The reference is to the Moving Target Indicator (M. T. I.) and it can be said without doubt that the sales that the AR-1 enjoyed in later years were due to the success of this piece of equipment, The conditions on site at the time were chaotic with people being transferred from the mainland and Island recruited staff being introduced. It was amid this confusion that the first M. T, I. was developed by Mr. P. Bradsell (still at Plessey, Cowes) specifically for AR-1. The first paper design was entirely with valves but the development in its transistorised from revolutionised the modern radar and is now standard equipment with all major Air Surveillance Radars, (AR5, AR15, AR157, AR16 and many more), M. T, I, suppresses all echoes from static surroundings and shows only those which have changed position. With normal video several targets are lost as they travel over the 'permanent echoes'. The M.T.I. was soon linked with the DASR-1 (but not used with it until much later however), several of the latter had been installed in Sweden and it was here that M.T.I. was initially proposed. However, a senior engineer working for the French (SNE) Company put forward the idea that M. T. I, was not necessary and that his Airborne Target Indicator (A. T. I.) would be superior for getting rid of unwanted ground clutter. M. T . I. works by suppressing permanent echoes whereas A. T. I. works by enhancing the echoes from airborne targets, i, e. two completely different principles. A. T. I. was obtained with back to back aerials by adjusting their tilt levels and applying the right swept gain to each beam. In this manner airborne target enhancement was obtained. However, the purely electronic M. T. I. system was soon seen to be the ideal solution to the problem of distinguishing the moving objects from their surroundings

Fig 8

Fig 9

The next completed system was the MR100 - an I S'-band radar using thenow standard 750kW Tx/Rx and a new SNE reflector. Only one was produced however and this was installed at Vickers airfield at Wisley in Surrey.

We now pick up the threads of the AR- 1 development. The AR- 1 itself had evolved naturally from the need for a high definition, general purpose, Air Surveillance Radar, The three basic building blocks now existed:

Aerial AWS- I Tx/Rx 750kW and the newly developed M. T. I.

At the time (1962) it was known that there was an Air Force requirement for fifteen to twenty radars to replace the Cossor airfield control radars which they had been using. The paper design was submitted to them and one of the radars was subsequently installed at Cowes and used to demonstrate the capabilities of M.T.I. The airforce carried out flight trials and proved the radar to be an unusually good and complete system, even though it was, as yet, experimental. The well arranged equipment room enabled good evaluation to be made, The (Decca) predicted coverage was greatly exceeded and it soon began to appear that the initial risk of this private venture would ultimately pay off, The AR-1 was launched onto the market in 1964.

Figure 9 illustrates the organisation at this time and why the Heavy Radar Laboratories section was selected for transfer to the Isle of Wight.

Mr. R. L. Burr was appointed by Mr. Easy to full control of the Heavy Radar Laboratories. Referring to Figure 9 personnel from sections double outlined were transferred from Chessington and were augmented by considerable local recruitment, the total work force was in excess of 600.

By 1964 building work was virtually completed and on July 17th 1964 the buildings as they are today were officially opened.

Within a year of the official opening, the Decca association with heavy radar ceased completely when their interests were acquired by the Plessey Company in April 1965. (Everything double outline on Figure 9). Thus the team that had taken nearly two decades to form from tentative beginnings passed lock, stock and barrel to new owners. The team however, as we shall see, stayed under the direction of Group-Captain Fennessey who was undoubtedly anxious to see AR-1 through to its conclusion, knowing that eventually it would be a tremendous success.