Recollections of BBC engineering from 1922 to 1997
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Equipment Department

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Equipment Department - the beginning

By L.G.Smith*

* Complied and edited by Martin Ellen, from several articles written by L.G. Smith between about 1970 and 2004.

E.D. and S.D.& I.D

Before the war, there was a Station Design and Installation Department and an Equipment Department.  S.D.& I.D., under Mr MacLarty, was responsible for the planning; design and installation of transmitters and also for the wiring and power supplies in studio premises.  The more technical aspects of the low frequency side of broadcasting were the responsibility of Equipment Department which had a workshop that made the items and a very small Designs Section under Mr. Colborn.  The actual number of Designs Engineers was probably about six in 1929.  Broadcasting House and the studios, as far as the lighting, heating and electrical cabling were concerned, were the responsibility of S.D. & I.D., but the technical equipment (microphones, amplifiers, switching, control room and studio cubicle equipment) was the responsibility of Mr. Colborn’s Designs Section.

Avenue House, Clapham – the original home of Equipment Department

In 1929, 87 Kings Avenue, Clapham was the home of the BBC Research Department and Equipment Department - these departments having been formed from the single Development Department.  The building was a former residence of the governor of Brixton Prison, which was within 50 yards of Avenue House.  The Designs Section of Equipment Department occupied one room on the top floor. It was responsible for the design, planning and installation of the original 'grey equipment' installed in the Regional Control Rooms and in Broadcasting House.  Equipment before that time had followed the Post Office practice of heavy mahogany wooden tables and desks.

The Head of Equipment Department was F.M. Dimmock, father of Sports and OB presenter Peter Dimmock.  The only ladies on the staff were Mrs Lewis, who brought round the tea at one old penny a cup, and a part-time cook. These two provided two sittings of lunch in what used to be the lodge of the governor's house.  All secretaries, typists and the switchboard operators were male; one of the switchboard operators, Holmes, in later years became Head of Research Department drawing office at Kingswood Warren.

'Conditions of Service'

Office hours were 9.30 to 6.00 and every other Saturday 9.30 to 1.00.  There were no proper salary grading systems, no overtime, extra duty pay or leave in lieu; everyone worked to do a good job and many evening and all-night sessions would be worked to clear faults without thought of time off.  There were 'moans'.  A cost of living allowance had been paid to staff working in London at Savoy Hill and within 10 miles of Savoy Hill to cover the many premises in central London.  When the headquarters moved from Savoy Hill to Broadcasting House, Avenue House was outside the 10 miles radius and the allowance was ceased.

In the economic depression of the early 1930s a meeting was called by Sir John Reith of all BBC staff in the Concert Hall of BH to consider a contribution by deduction from pay, to open a centre for the unemployed in Gateshead.  Equipment Department staff, including workshop staff, came up from Avenue House and a representative from the Ministry of Labour sat on the platform with Sir John to say his piece.  After hearing all about the project, suddenly one of the workshop staff got up and said, "Before collecting for the unemployed in Gateshead, what about the workshop staff at Avenue House? I have been working for the BBC for five years and get only 6d an hour," or words to that effect.  He was followed by about half a dozen others.  Sir John immediately adjourned the meeting, called for any other complaints, took the names of the workshop staff and arranged to see them all in his office the next morning, before continuing the meeting.  As a result many had their wages doubled and all had rises of some sort.  In those days we had a Christmas bonus equal to a week's pay, notified in a letter from Sir John.  Although a strict teetotaller, instant dismissal at the first hint of a divorce, etc. as I understand it, he was highly esteemed by all staff.  Everyone had the right of direct access to Sir John if occasion demanded.  A head-and-shoulders engraving of him was inserted in one issue of Ariel and this found its way to many office walls.

The need for manufacturing

It is difficult to appreciate that in the late 1920s and early 1930s virtually no commercial equipment was available to satisfy the standards required by the BBC. Components such as transformers, resistors, volume controls, etc. were therefore designed and made by ED. Resistors were made by turning slots in 1-inch diameter ebonite road and hand-winding these with resistance wire. Six such resistors about 4 inches long connected to a 24-way stud switch, also made in ED, formed a main volume control.  All components were tested before being incorporated into amplifiers and other apparatus, which were built on 3/16-inch steel panels for rack-mounting. Terminal blocks for these units were of 3/16- inch ebonite, having each soldering tag fixed with a nut and bolt.  Wiring inside the units was carried out in 16SWG bare tinned copper wire covered in red sleeving with all the wire running straight with right- angled bends.


Mr Lucking acted as liaison between the workshop and the rest of the department.  The workshops were contained in a separate brick building, the cable-forming and bay-wiring shop consisted of a small wooden hut, which reminded me of a seaside beach hut.  The works manager, a Mr Johnson, was never seen without the tatty end of a home made cigarette between his lips.  I have a vivid recollection of Mr Lucking, in an endeavour to cure Johnson of constant cigarette scrounging, repacking the centre of a "Players" with crushed match ends. Mr Johnson duly fell for the trap, which culminated in a display of fireworks in the workshops, and no more scrounging of cigarettes from designs section.

Building at Avenue House

When the design of Broadcasting House equipment was being discussed the provision of technical equipment required a considerable growth in the facilities provided at Avenue House.  There was adequate space in the garden, which had a large lawn (used for cricket in the summer lunch hours) surrounded by fruit trees.  At the rear of the garage a wood and asbestos bungalow was put up to house HED [Head of Equipment Department] and his small office staff, Mr Colborn and Designs Section, with the Drawing Office in a long room extending across the far end of the bungalow. Additional Designs Section staff were recruited particularly to deal with cable forming, which was a comparatively new idea to the BBC at that time, and the Drawing Office staff were increased to five.


This move was eagerly welcomed by the head draughtsman Allan Holden who had a particular hate for cats, and the move brought him closer to the high garden wall on which they used to sit.  Whenever one was sighted, the D.O. went into action with military precision, as long as "Uncle" Colborn was not in the office!  The two people on each side of the window bearing on the line of fire, opened the window as quietly as possible.  Allan then produced his catapult, the ammunition being made from the lead sheath of a Ipr./10 cable, and went into action.  Some reduction in this activity was forced upon us when a lady from one of the houses backing onto Avenue House garden visited H.E.D. with some of the lead pellets and sordid stories of broken windows.

Runner beans

Alan Holden lived very near Avenue House and as there was plenty of garden available, he started a little allotment outside the drawing office windows, which he cultivated in the evenings.  He proudly announced one day that he had planted some runner beans, so in his absence we dug up the beans and planted instead some giant sunflower seeds, which we encouraged Alan to water every evening.  When these were about three inches high they looked very similar to runner bean plants and Alan duly erected an array of bean sticks. At nine inches high we persuaded him he had to tie them first clockwise and when they still would not curl round, to try anticlockwise round each bean stick.  Alan was not a very knowledgeable gardener and it was not until the sunflower plants were about 2ft high that Alan realised what was going on. We did, however, enjoy a great variety of birds eating the sunflower seeds.

More building and a 300-volt shock

Research Department and Equipment Department expanded still further and outgrew the available accommodation.  Research Department moved first to Nightingale Lane and then to Nightingale Square, Clapham, and Equipment Department expanded into the whole of Avenue House and then into a new brick-built extension building alongside it.  This extension building housed the Test Room, with several small rooms for microphone and transformer testing, and the Drawing Office with three Design Engineers' offices occupied a second floor over part of the building.  The only minor faults in the design of the building were the omission of any staircase or other means of getting to the second floor and a new patent type of parquet floor to the Test Room.  The stairs were fortunately able to be fitted in before the building was finally occupied (although they were not wide enough to take the DO plan chests). The Test Room floor was more serious and its fault did not come to light till testing commenced.  In those days all the equipment required Low Tension (6 volts), High Tension and Grid Bias battery supplies, and the HT of 300 volts was available to the units under test via naked brass terminals always fully alive at HT voltage.  Safety precautions were not known in those days and one just had to remember not to touch the bay framework when doing up the terminal. In the new building every time anyone touched one of these terminals a 300-volt shock was received and this was traced to the floor, which although made of wooden block set in a 'muckite' of sawdust, had a resistance of a few hundred ohms.  This fault was initially overcome by providing each engineer with a small rubber mat to stand on.


Outside the front door of Avenue House there stood statues of two beasties, lion-like creatures about 4ft high.  These were originally painted all over cream but over the years were just dirty white, until after the extension was built, when the house was repainted by Bill Picket. He was a notable character from Building Dept., with a real sergeant major-type waxed and pointed moustache, who was so taken with the beasties that I think he spent more time on them than on the house.  He finished them in a dark chocolate colour with teeth and claws in gleaming white and tongue in red.  He managed to produce a most wicked look in their eyes.  So much so that one instinctively glanced over one's shoulder when going in the door in case of attack from the rear.  When Avenue House moved to Chiswick in 1958 the beasties were moved there and put inside the entrance hall, and I now understand they are in residence at Kingswood Warren.


Drawings at that time were drawn in Indian ink on tracing linen.  Circuits had resistors drawn as about a dozen zigzags, all lines at the correct angle, and transformers needed about 20 semicircles joined with straight lines to represent the coils.  All lettering was hand-done—no stencils or stick-on labels for circuit components.  Tracings then had to be taken to a firm in Kingsway for individual prints to be made, which were in the form of white lines on a bright blue paper—hence the term 'blueprint' used nowadays in the context of any new National Health proposals or whatever.  Later these reproductions became dyeline prints—brown lines on white paper, much easier to mark up and revise.

Test Room

Having learnt something about ED Test Room activities by coming in on my Saturday mornings off-duty, I began working there part-time and then full-time as the workload increased with the equipment requirements for Broadcasting House and later the Regional control rooms.  Although it was a long time before I was officially designated an engineer from being a drawing office tracer.

Amplifiers were tested for frequency response by switching in a thermocouple from input to output to measure tone from the bay-mounted variable oscillator to a fixed oscillator mounted as far away as possible high up on the other side of the room.  Most of the time was taken up by tapping the glass of the thermocouple meter to get as high a reading as possible.

Testing microphones

We still enjoyed a few lighter moments, particularly at the expense of one ex-Research Dept. engineer whose responsibility in Test Room was the testing of microphones. He used a large coffin-shaped box, which had the microphone under test at one end and a loudspeaker at the opposite end, into which tone was fed.  The box was very heavily soundproofed and the lid fitted with a very large number of screws requiring removal for access.  A headphone jack was provided to check that the loudspeaker was working.  Time after time the diaphragms were removed from his headphones, giving him the onerous task of removing the screws and lid to check the loudspeaker. He never seemed to learn.

Battery charging

Staff Sets Section lived in a little brick building at the back of the garage and their main occupation was battery charging, since all "wireless sets" in those days worked from batteries.  Dry batteries for H.T. and accumulators for L.T.  (To light the valves as it were).  The accumulators were charged from motor generators, although I believe someone had rigged a small arrangement operating from the mains for "home office" accumulator charging.  The whole room presented a rather terrifying aspect to me, as a junior, with the noise and the sparks and the smell from the acid fumes, with loose bits of wire connecting a host of different sized accumulators in series and parallel.  Carboys of acid and distilled water and the dull glow from long sausage shaped resistance lamps.


The garage itself possibly held about eight vehicles, the largest probably being a one ton truck, although the main interest to staff was the ability to get cheap petrol at I think 1/6d. a gallon from a hand operated pump.  The most notable vehicle was Mr Lucking's two sealer Morris Cowley, which was never cleaned as he held the view that dirt protected the paint.  He did at last decide to repaint it, and started on the doors, which he took off and did a "real Job" on them in the workshop spray booth.  For many months after, the car was to be seen with two highly polished maroon coloured doors, but the remainder of the car as dirty as ever.


Up to 1938, most of our regional premises, and Broadcasting House of course, were equipped with apparatus operating from batteries.  The only mains-operated stations were Bangor  - a small attic centre with a small control room operating from the mains (via a large h.t. rectifier, supplied in duplicate, and l.t. rectifiers operated from one large transformer, with an l.t. rectifier for each amplifier) and Maida Vale which operated in a similar way.  In addition there was the training school premises in Duchess Street.  These were the only equipments working from the mains.  All other premises operated from batteries charged from mains-driven generators.

Amplifier design

Mr. Colborn and Mr. Lock, who was Mr. Colborn*s chief assistant designer, designed some rack-mounted OBA/8 amplifiers, called APM/1s (Amplifier Programme Meter).  The OBA/8 amplifier was a very versatile microphone-to-line level amplifier with a main control on it.  It had a four-channel mixer, the MX/18, which went with it and was used for O.B.s.  The new design made these into rack-Mounted units, providing a single output for feeding to line and a monitoring output for feeding headphones, and operating from microphone level. In order to make these usable in a control room, we needed some trap-valves, and new designs of trap-valves, TV/17 and TV/18, were devised for the purpose.  This equipment had been through the drawing office, it was being made and only a very small number, if any, had actually been delivered in the summer of 1939. [See Wood Norton in the Second World War].

Regarding trap-valve amplifiers, the TV/17 had one input and four outputs, and the TV/18 had two inputs, each having two outputs (input 1 fed outputs 1 and 2, input 2 fed outputs 3 and 4).  There was rather a to-do about the labelling of these; the circuit diagram said input 1, for instance, but when you looked at the labelling on the amplifier it said input A, which caused considerable confusion, especially in the designations on the jackfields.  The details of these amplifiers can be found in Technical Instruction ST.5. They used the then ubiquitous AC/SP3 valve, and of course each had four valves, the TV/17 having one input to each of four grid circuits, and the TV/18 consisting of two amplifiers, each with one input and two outputs.

Broadcasting House

Broadcasting House came into service in May 1932. The studios were contained in a tower built of blue engineering brick with very few doorways or other openings.  This tower was surrounded by corridors and offices constructed as normal over a steel girder framework with no girder connection to the studios; thus these were well insulated from outside acoustic interference and were further insulated vertically by quiet areas such as libraries and storage areas.

A fact not generally known about BH is that it has an artesian well, which provides an excellent programme earth.

The Director of Administration at that time was of the opinion that the whole of the BBC revolved around him and his department.  Engineers were but glorified plumbers who should be confined to the basement and the eighth floor.  He supervised the six pageboys, who sat in the entrance hall to run errands, and he stood about in black jacket and pinstriped trousers, wearing a monocle.  One day he sent a new monocle to a small workshop attached to the eighth floor to have it drilled for its black ribbon.  As he did not specify where it was to be drilled, it was returned to him with a single hole in the middle of the glass.  Not a person popular in the Engineering Division.

Regional Control Rooms

Re-equipment of the Regional Control Rooms proceeded after Broadcasting House and I was very involved in this work.  In Newcastle the BBC occupied what had previously been a maternity lying-in hospital, Cardiff was done in June 1934 and occupied an old house in Park Place, and this was followed by Glasgow where the studios and Control used an old house in BIythswood Square.

Newcastle control room was originally situated on the first floor and the 'new' control room was installed on the ground floor.  Mr Colborn came up for the handover to Mr Chadder, the Superintendent Engineer, and after demonstrating the new relay switching and amplifiers until a late hour in the evening, since the Post Office circuits were teed into both control rooms, Mr Colborn and Mr Chadder put in the line fuses to the new control room, though which passed all the programmes to the North and Scotland. They then took over control, causing chaos upstairs and much amusement downstairs.

Plugs and sockets

The only plugs and sockets available commercially were those of 5 or 15-amp, as used for domestic power supplies, but when Broadcasting House was nearing completion, the need arose for plugs and sockets for two specialised situations.  The first amplifier to operate directly from the mains was designed to feed the RK loudspeaker in studio cubicles, the LSM/1, and this required plugs and sockets for input, output and mains supply.  These were designed in the Drawing Office and I think made up in the Workshop from two-inch diameter ebonite rod.  The second application was again a purpose-designed plug and socket used as a universal skirting socket. Although the old Reisz carbon microphone was the standard mic., a few condenser microphones of RCA manufacture were coming into use and these incorporated a valve amplifier, adjacent to the microphone, which needed HT and LT supplies. (At that time it was standard practice for all microphone or 'A' amplifiers to be located in the Control Room.).  Hence the need for an 8- pin plug to which the different microphones could be connected, using different pins in the plug for differing mikes.  This plug, of a size unheard of in those days, was about four inches diameter with eight pins about 1/8" diameter.  It was made of plastic and its successful introduction gave Designs Section great satisfaction.


There is no doubt that the small band of engineers under Mr Colborn laid the foundations for the high standard of BBC sound equipment and engineering.  They set a high standard of quality and freedom from interference unheard of in the commercial world at that time. The problems of crosstalk, decoupling, switching clicks and so on were met for the first time and their investigation and cure involved much discussion, experiment and late night working.  There was no-one to ask who had met the problem before. There were no small diodes and suchlike to hang in the wiring, and no electrolytic condensers.  The introduction of 25µF condensers in one fault cure I remember entailed finding space and mechanical mounting for condensers that were about 6in x 5in x 8in high. One of these across each of a dozen relays was indeed a major exercise. The standard 'anticlick' device was a 2µF condenser (about 2in x 2in x lin) in tin case in series with a 600-ohm 'works wound bobbin', wired across the coil of the relay.


Site installations were planned virtually to the last tag before site work began.  All amplifiers, jacks, fuses, etc. were allocated to specific circuits and wired directly between bay tag blocks.  No flexibility was provided by a distribution frame, which was only used for circuits leaving the control room. Equipment Department wiremen, under a chargehand, could therefore be sent to site with all the information, and apart from the initial and very rare supervisory visits, engineers did not visit the site until the installation was virtually complete and ready for testing.  The chargehand would provide written test reports, one of which, famous for its technical content, merely stated, "I am pleased to report that the boys' colds are much better."  At least it showed an awareness of the human factor in management!   He was one Freddie Mott, an elderly man, very unobtrusive but a superb wireman.  Every wire to a jackfield, etc., curled to exactly the same curve with a buttonhook, interbay cables laced, covered with insulating tape and finally finished with yellow empire cloth tape and never, ever, a wrong connection or a dry joint.  All wiring was carried out in lead-covered 1pr/10. No multicore cables were used for programme wiring in studios or control rooms until 1940.

T&D claims of the thirties make illuminating reading.  Twenty-four hours' COB allowance for engineers was 16 shillings, lunch 2s 6d, evening meal 3s 6d, late night refreshment allowance for working all night 2s 6d and no compensatory leave, unsocial hours allowances or London weighting!

Testing generally started with an examination of every soldered joint for 'dry joints' (no resin-cored solder or electric soldering irons) and a buzzer test for continuity of the wire between its soldered terminals.  After everything had been shown to work, frequency runs were taken, not only on every amplifier but on combinations and permutations of 'A', 'B', 'C' and 'D' amplifiers.  All these were done by switching a thermocouple between input and output at every frequency and tapping the meter like a barometer till it gave the highest reading.

Equipment Department in the War

During the war, Equipment Department was split up because before the outbreak of war, it had not been considered that Design Section engineers would be used as designers, but would have assisted in the running of the broadcasting service.  At the outbreak of the war they had been required to report at various transmitting stations and only Mr. Colborn and Mr, Stentiford had remained in London rebuilding the B.H. emergency control room.   Although the Designs Section had been broken up, some members of it, in particular Messrs, Osmond and Trefor Williams, had gone up to Droitwich and joined S.D.I.D., who had been evacuated to Droitwich when war broke out. On 7th July 1941 I was transferred from the Wood Norton staff, where I had been an S.M.E., back to London to join Mr. Colborn's staff, who then had offices in the Langham Hotel.  One or two others also came back to London, because it had become apparent that there was a very great deal of installation work required on various projects, now that the full implications of Broadcasting in wartime had been understood.  I was brought back to London particularly to plan the installation of what was then known as the P.R. building, otherwise No. 200 Oxford Street. This was Peter Robinson's store that had been taken over by the BBC and was to be used for Overseas Service broadcasting.

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