By Richard Harris. Updated 2021-02-27.
All outside broadcast (OB) units need electric power but supplying it lacks the interest of the OB trucks themselves. At BECG our thoughts turned to this vital subject with our acquisition of a 1953 BBC generator truck. In this article, we survey the various ways in which power was provided for BBC OB trucks and look in particular at the 10 generator trucks that the BBC operated.
Power can come from the public mains supply, which was often sufficient for radio, small film (and later video) production and news units. Smaller units could also be powered from batteries, which became more common as technology advanced.
Television requires more power and it was sometimes difficult to find a local mains supply of sufficient capacity. Power is needed to run the television equipment, heating and lighting in the mobile control room and associated vehicles. In addition, there is often a substantial requirement for production lighting. Mobile generators can satisfy this requirement.
Table of Contents
How much power?
Early valve-based equipment used more power than transistor units do, and produced more heat. Typical requirement for a 1950s or 1960s OB unit might be:
- Four cameras 2kW
- Picture monitors 1.5kW
- Associated equipment (pulse generators, amplifiers, test equipment) 1.5kW
- Sound systems 0.5kW
- Operational lighting 0.5kW
- Heating and cooling 3kW
- Auxiliary equipment 2kW
So the total load could be 11kW, approximately 46 amps at 240 volts. A typical unit would have an 80 amp supply intake, using a BICC connector. There might also be other vehicles to power, such as radio links, a recording unit and a GPO lines van.
Lighting would depend on the location and programme. For example, 20 lamp heads, at an average of 1kW each, would require 84 amps.
Local mains supplies in the ‘50s and ‘60s were based on 60 amps per phase; only large public buildings and industrial sites had higher capacity or three-phase supply.
Early days
The first OB unit, introduced in 1937, comprised three vehicles: a mobile control room, transmitter and a generator van, the interior of which is shown below. The second unit, introduced 1938, also had a Merryweather 80 foot wooden aerial ladder vehicle.
The BBC only had ten power generator vans operating from London and Manchester, although there was also one based in Scotland. In the 1980s it was decided to hire-in generators as required, generally from lighting companies (mainly from Lee, Lee Northern, Telefilm and S.G. Fenner). Power requirements were increasing and it was becoming desirable to have a second unit on site to share the load and act as back-up. It was not thought cost effective for the BBC to invest in larger additional units. The lighting companies were well equipped by that time and had sufficient plant to provide back-up. However, the BBC did maintain a number of smaller trailer mounted units.
The BBC units were known as power vans and given the identity “P”. We have the following information about them:
- P1 AEC Regal 1 Coach chassis, 25kW.
- P2 FLR 184, 1939, AEC Regal 1 Coach chassis, 25kW.
- P3 Operated out of Manchester, believed similar to P5, scrapped.
- P4 RXX 905, A-905, Austin Loadstar, built 1955, sold 1968, converted to a flatbed. Restored 2009 with new-build box body.
- P5 NGF 728, B-728, built 1953, Bedford ML, still in service (Aintree) 1987, bought by BECG in 2020.
- P6 Bonneted ‘50s Austin.
- P7 482 FYW, Austin FG, 27kW, not silenced. Disposed approx. 1987. Generator used at transmitter station in Yorkshire.
- P8 SLL 195F, coachbuilt Bedford TK, Ford generator, 33kW, near silenced.
- P9 WGN 256G, coachbuilt Bedford TK, Ford generator, 33kW, near silenced.
- P10 LUU 353P, Bedford TK, 466 engine. Volvo Penta Marine generator engine, 96kW, fully silenced.
P3 and P5 operated from Manchester; P6 and P7 from the former BBC OB base at Kendal Avenue, west London.
There were also a number of trailer-mounted road-tow generators. Some vehicles, particularly versions of the Roving Eye, had generators built in. Later on, satellite up-link trucks generally had built-in generators.
The towable generators were used with radio links vehicles (often on a remote hill top) or a remote single camera unit (such as at the end of an airfield runway or the far corner of a racetrack). They were also used with some versions of the Roving Eye.
These generators for television were more advanced than the temporary plant used on a typical building site. Most had controls for both frequency and voltage, with a degree of stabilisation. Many could be locked to 50Hz frame rate from the OB unit’s synchronising pulse generator. They also had acoustic and exhaust treatment, offering some level of silencing.
History of P2
FLR 184 was similar to P1 with both being built on an AEC Regal 1 Coach chassis. The Mobile Control Room (MCR), and a transmitter van were built into similar vehicles to form an OB unit. The unit was put into service in 1939. Power generation capacity was 25kW.
History of P4
RXX 905, plant No. A-905, Austin Loadstar generator unit, was built in 1955 and remained in BBC service for 13 years until 1968. The next owner removed the generator and box body to fit a drop-side flatbed.
In 2009 Brian and Barbara Morgan bought the unit for restoration. They found drawings for the original box body and made a replica. They did not restore the interior but used it as a day van.
Derek Hooper, who was garage workshop manager at Kendal Avenue, described the commissioning of the unit: “…after the chassis (no.255874) had been ordered, probably late 1954, it was sent to be built under scheme no. 2/7909 and allocated the under-construction number of UC 11. This was authorised on 26/1/55. It was to become Power 4 (P4)”.
History of P5
NGF 728, plant No. B-728, Bedford ML chassis, was built in 1952 and the vehicle entered service in 1953. It has a petrol engine, whereas the generator has a Perkins six-cylinder diesel engine. Ken Gregory (retired operations manager, Manchester) tells us its first job may have been to provide power for coverage of Roger Bannister’s successful 1954 attempt at a sub four-minute mile.
History of P6
Little is known about this vehicle. It was based in London and was a “bonneted” ‘50s Austin.
History of P7
482 FYW, plant No, 482-A. This Austin FG with a 27kW generator, not silenced, was disposed of around 1987. The generator set was re-used at a transmitter station in Yorkshire.
History of P8
SLL 195F, with its Bedford TK coachbuilt body, was similar to P9. It had a Ford generator, 33kW, near silenced.
History of P9
WGN 256G, with a Bedford TK coachbuilt body had a Ford generator, 33kW, near silenced. There is a commercially licensable photo in the BBC archives, which can also be found here: https://www.pinterest.co.uk/pin/144467100534063530/
History of P10
LUU 353P was a Bedford TK with a Bedford 466 engine. It had a Volvo Penta Marine generator engine, 96kW, fully silenced. The 240 gallon fuel tank gave 31 hours running at full load.
P10 was the last power van (generator) operated by BBC London.
NLM 6V Ford chassis operated by BBC Scotland
Generators from lighting hire companies.
Built-in generators
BBC vehicles generally did not have built-in generators, due to noise, weight and space considerations, although there were some notable exceptions.
Two units built in 1951, designated PTA 1 and PTA 2 (Power Transmitting Aerials), combined a 15kW generator with a transmitter and a 100-foot fire escape ladder as an aerial support. The generator had sufficient capacity to power an accompanying control room. These vehicles were built by Merryweather, a company specialising in equipment for the fire service. Mounted on AEC Regal 3 coach chassis they were registered as KGH 565 and KGH 566.
KGH 565 – PTA 1
KGH 566 – PTA 2
Roving eye RE-2, built in 1957, had a built-in generator. Bob Matthews says, “In order that the vehicle could operate on the move, an air-cooled petrol-engine generator was installed at the rear. This item was provided by Max-Arc Ltd. of Walton-on-Thames, a company specializing in arc-welding equipment for use in countries where water is at a premium. This obviously heavy item was to prove embarrassing when the driver wished to accelerate, as a racehorse gallops at about 40mph in a few seconds from a (nominal) standing start. No commercial-type vehicle can cope with that!” The generator was built into a removable box, made from acoustic board, with an acoustic labyrinth fitted into the cooling air intake.
The next version of roving eye, RE-5, also had a generator mounted in the rear, but the extra weight did not improve its performance. Bob Matthews said: “The vehicle was designed to rove, but I doubt if it ever did”.
Later roving eye vehicles used trailer-mounted generators, which also powered radio links vehicles and single camera units at remote sites. These trailer units had the designation letters P.G.
At least 13 trailer generators, mostly using diesel as fuel, were available in London in the 1970s. Power outputs varied between units, from 3 to 12 kW.
As equipment became smaller and lighter, with lower power requirements, battery operation became possible in many situations. However, modern satellite trucks, with their HPAs (High Power Amplifiers), generally include an on-board silenced generator.
Looking forward
BECG is delighted to have bought P5 (NGF 728). We will restore the generator unit to complement our Project Vivat recreation of a 1950s BBC – Marconi OB truck. Some restoration work will be necessary on P5 before it can be used and displayed.
This is how P5 looked recently, in October 2020:
