Thirty Productive Acres 

15 April 2022 tbs.pm/75043

The BBC research engineer… ‘He can truthfully say that he is kept busy, a supply of problems and a demand for solutions both flourish in his profession’

 

 

A BBC Research Engineer describes simply some of the work undertaken at Kingswood Warren – his department’s headquarters in Surrey. Helicopter and barrage balloon play their part in the work of BBC research engineers, who have recently designed a machine to replace the ‘echo room’

 

Radio Times Annual 1954 cover

From the Radio Times Annual 1954

RESEARCH into the technical side of broadcasting is not an easy subject to discuss in ordinary language. Even those engaged in this kind of work find it difficult to talk shop over tea without covering the table-top with symbols and circuit diagrams. As a result the research engineer is sometimes a little disconcerted when asked to explain exactly what he does all day in his laboratory. He can truthfully say that he is kept busy, for a supply of problems and a demand for solutions both flourish in his profession; and he may well be in a position to assert that, but for him, the reception of BBC programmes would not be as good as it is today. Beyond this point he may find it difficult to go. It is hoped, however, that his limitations will be indulgently borne in mind in reading the following short account of the work of the author and some two hundred of his colleagues — engineers, physicists, draughtsmen, and instrument makers — in the BBC’s Research Department.

Most of the staff work under pleasant conditions in a large and delightful old country house at Kingswood in Surrey. To suit their highly specialised needs, some additional buildings have been constructed and the mansion itself has been considerably modified. For all this, the outward appearance of the building remains much the same as when it was built. The architect who designed it could hardly have dreamt, however, that a view of his building, similar to that pictured here, might one day be displayed in colour on a cathode-ray tube in one of the rooms, now laboratories, within its walls. Neither could he have dreamt, even after the heaviest of meals, of the peculiar frameworks of wires and tubes that are nowadays hoisted above the lawn on masts or by means of barrage balloons.

It will have been gathered that colour television is one of the problems on which the department is now working. This is indeed the case, although it will inevitably be some years before viewers can expect to see a colour television picture in their homes. Aside from the enormous amount of technical development involved, the cost of such a scheme will make its eventual adoption a decision for the politician, rather than for the engineer.

 

A drawing of a castellated mansion

1841: Kingswood Warren in the good old days of Thomas Alcock, Esqre

 

The mansion in 1954

1954: the mansion, now the home of BBC Research engineers, has altered little, but new laboratory buildings have sprung up almost out of sight

 

On the other hand, one of the most important jobs of the Research Department’s engineers is to keep in close touch with major advances in their field — and colour television certainly comes into this category — so that they can give detailed and practical advice on these matters when the time comes. To this end, a team of engineers is busy setting up an experimental colour system, based upon a scheme now widely agreed upon in America, and experiments are being carried out to determine the best way of conveying and mixing the colour ingredients to obtain a pleasing picture. It would, however, be unfair to attempt here a summary of the results obtained at this early stage.

Another major development, a little closer to hand, which members of the Research Department are still busy investigating is V.H.F. (very high frequency) broadcasting. This means using wavelengths much shorter than any marked on the short-wave range of an ordinary wireless set. It is, however, the only way of getting round the shortage of space in the medium waveband and the interference from foreign stations which impairs present-day reception. The fact that such transmissions could not be received on ordinary sets is a pity. On the other hand, it makes the introduction of another innovation — F.M. (frequency modulation) — a more practical proposition, on the grounds that, if a thing has to be different, it may as well be very different.

F.M. is one of those subjects that cannot be explained in simple terms; but its importance may be gauged from the fact that it should enable a nation-wide system of V.H.F. broadcasting to be installed and run at appreciably less than half the cost of a similar system built along conventional lines.

 

A man with a strange aerial

This engineer tours the country in his mobile laboratory measuring the field strength of BBC transmitters

 

Two-year Wrotham Test on F.M.

The work involved in an investigation of this kind varies from scaling an aerial mast to sitting in an office working out a statistical analysis of listeners’ reports. It all takes a long time for, among other things, it is essential that tests are made under all kinds of weather conditions. For instance, tests on the quality of reception from two experimental transmitters at Wrotham in Kent have been carried out for over two years in an effort to make a full appraisal of this type of transmission. Moreover, the volume of work in this field is rapidly increasing, for a group of nine F.M. transmitting stations will soon be in operation at various sites throughout the country. Research Department engineers are being called upon to advise upon the precise location of the transmitters and the design of the transmitting aerials, and they will be responsible for measuring their performance when they go into operation. These investigations have become all the more important recently, since it now seems very likely that television, too, may eventually have to be broadcast on much shorter wavelengths than it is today.

 

A woman works at a machine

Coil winding in the workshops of Kingswood Warren demands nimble fingers. Here is an expert at work

 

Meanwhile, until such time as this new type of broadcasting becomes fully established, the limited number of medium wavelengths available to the BBC for its domestic programmes makes it essential that the maximum possible area is served by each transmitting station. Measurements of the quality of reception are continually being made all over the country by Research Department engineers in their specially equipped vans — a job which means few nights at home and a succession of colds during the winter. Sometimes a helicopter has been used to measure the way in which the radio waves spread out above a transmitting aerial. Tests of this kind, together with calculations in the laboratories, have provided many ideas for improving listeners’ reception. For example, research of this kind recently lead to modifications being put in hand on the aerial system at the Home Service transmitter at Brookman’s Park. On occasions, experiments on the efficiency of a new aerial have been made on a scale model — one tenth actual size — erected in the grounds at Kingswood, before the aerial itself has been put into service.

There are, however, many links in the chain of broadcasting before the transmitter and these, too, receive a good deal of attention. Under this heading comes the complicated subject of studio acoustics. The various types of studio — television, concert, drama, talks — must have suitable acoustic properties and require different acoustic treatment. Think how disturbing it would be if the announcer appeared to be speaking from a bathroom or the orchestra seemed to be playing in the middle of Salisbury Plain! Yet these effects could be simulated by appropriate — or, rather, most inappropriate — acoustic treatment of the studios concerned.

 

A helicopter

‘Research engineers are being called upon to advise upon the location of transmitters and the design of transmitting aerials…’ and often call in the help of a helicopter. Note the aerial under the nose of the plane

 

To decide how best to treat a studio which is known to be bad is seldom a straightforward matter. One of the ways in which a studio is tested is to produce in it short bursts of sound, of given pitch and measure the way in which they die away. Ideally this should be done over an appreciable part of the audible range, from very low-pitched to very high-pitched sounds, and an ingenious method of obtaining all this information in a single picture has been developed by Research Department engineers. Such a picture, called a pulsed glide display, consists of a large number of white lines, each of which represents the way in which one of the test sounds dies away as the reflections from the walls of the studio become weaker and weaker. Taken as a whole, the white lines form to the engineer a graphical picture of the acoustic properties of the studio (illustration below).

 

A waveform

This is not an Everest route card: the engineers call this diagram a pulsed glide display, which they use in the testing of studio acoustics

 

Echo-producing Machine

Another device recently developed is a machine which, when inserted in the broadcast chain following the microphone, tricks the ear into thinking the reverberation of a studio to be much greater than it really is. It is, in effect, a kind of echo-producing machine and relies for its working upon repeatedly recording and replaying a programme on a specially designed type of magnetic-recording apparatus. Hitherto it was common practice to add reverberation by passing the programme from a studio through a so-called echo-room before sending it on to the transmitter. The new method has the advantage of economy of space and greater flexibility, though in some cases its performance may not be quite so effective as that of an echo-room. Experimental models have been in operation for some time and have proved particularly useful in the Television Service, where there is often great need to increase the reverberation of the large, but heavily deadened, studios.

Two microphones

The new ribbin [sic – ribbon] microphone is considerably smaller than the familiar model designed fifteen years ago

Microphones require constant research and development, since many types are required when the programme material may vary from the full sound of a symphony orchestra to the click of a ball against a cricket bat. Recently, for instance, a new ribbon microphone has been developed which is very much smaller than the old familiar type, known by sight to thousands of listeners, which was designed in the Research Department some fifteen years ago. Experimental models of the new microphone, also designed in the Research Department, have already been used in the Sound and Television Services — in fact, they proved their worth in many broadcasts at the time of the Coronation.

Only a few of the Research Department’s activities have been mentioned in this brief survey. It is hoped, however, that enough has been said to show that these thirty-odd acres at Kingswood are far from unproductive.

A final important point is that it is not only the BBC which reaps the benefit. Through reports and articles—more than twenty articles were published in the technical Press by members of the Research Department in 1953 — broadcasting organisations all over the world can read of the more fundamental aspects of the work that is carried out.

 

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