There was a desk in each end area (Cubicles 1A and 1B) and a common Studio 1 between them which could be controlled from either cubicle. With two identical self-op areas the "hot seat change-over" was avoided. This hadn't been a problem until stations began continuous broadcasting for most of the day and not closing down to a network for short periods as had been the practice in the early days of local radio. Eventually a fourth smaller area was provided for meeting and greeting guests before going on air and for answering incoming telephone calls which until then had been answered in a cubicle or Std 1 which often proved to be impractical. A variation of this in-line arrangement was the four-square layout adopted at Radio Merseyside which, while improving sight contact between the areas, proved rather costly to build.
The telephone answering and broadcast equipment was originally 'Telespot' which the GPO (the predecessor to BT) had developed for the particular needs of broadcasters using their standard 20-way key and lamp unit. This was later replaced by 'Telecaster' which was a digital system based on commercially available call handling units.
A further improvement over Mk II was the addition of a separate Apparatus Room which serviced the technical areas and handled all the lines and communications which hitherto had been located in two or three equipment bays in the Ops Room of the earlier stations.
The Mk III desk was designed specifically for local radio by its own engineers and was fully stereo. At some sites the Mk III was installed in a mono configuration which was later upgraded to stereo as funds allowed or the BBC felt obliged by the imminent arrival of an independent radio station, which were always stereo from day one, on a station's patch. The central mono monitoring unit was changed to one with stereo PPMs fitted and the programme chain had amplifiers installed in the RH side to complete the conversion.
Mk III was designed for ease of use and very quickly found favour with presenters. It was built by Equipment Department at Avenue House, Chiswick.
To the left are two Gram channels, four Outside Source channels selecting from a 24 way OS mult. of, initially, BT music and control lines (now mostly ISDN sources) and telephones and an RBR channel with a 10 way selector. Each OS channel has a switch to select either cue or clean feed to its source together with CL telephone answering and ringing provision (now little used). Above the gram faders is the intercom LS and radio car talk-back control.
The centre section has the presenter's mic fader and two cubicle guest mics for self op and two mics in the adjacent studio. Above is the central comprehensive metering, station intercom and Direct to Transmitter selector buttons which route a sustaining network overnight or other programme material directly to the transmitters thus releasing the desk for rehearsal or local production work.
To the right are the dual switchable input repro channels for tape and carts whose second input has over the years been used for sources such as cassette tapes, DAT recorders and Mini Discs. Most recently the primary inputs have been used for the Radio Man computer playout system now almost universally installed in the BBC's 39 local radio stations. In fact the ease with which the desk has accommodated the digital revolution from which we all suffer is testament to the versatility which was designed into it over forty years ago. The only modification with the arrival of Radio Man was to raise the whole carcass by 40mm to allow the VDU screens to conform to current HSE legislation!
Above the repro faders are the audio monitoring controls, compressor/limiter switches, cue send selectors and five recording selectors for tape, cassette or cart with their associated remote record start and indication, now largely redundant since the advent of Radio Man.
All the units were part of Equipment Department's coded equipment scheme and were thus immune from modification by the local engineers to enable interchangeability
for maintenance. For this reason a separate panel was specifically provided where local modifications could be added to meet a station's individual requirements.
Usually a second conventional studio/ cubicle configuration (Studio 2) was also provided elsewhere in the station. At Radio Leeds which had a very large Studio 2 capable of seating about 150 people (the building was formerly a church) a Mk IIIA was built which had 12 additional microphone channels which could be activated by pushing an 'Overdrive' switch which took the installation from a standard desk to a multi-mic mixer. This enabled large audience participation and music sessions to be broadcast.
Among the innovations was the use of Hytips to connect the desk to the outside world instead of soldered tag blocks. Initially a single equipment bay was provided in each cubicle with PSUs , amplifiers and a jackfield as in this
1979 picture of the original mono Cub 1B at Radio Leeds. Later it was found that all the bay equipment could be tucked into the carcass and the bay was dispensed with as in this 1981 picture, below, taken at Leicester.
In the late 1970s a massive expansion of local radio was planned and Equipment Department found itself unable to cope with producing many desks in a short time. The Mk III design was given to an outside manufacturer who made desks for a few stations. Unfortunately the power supplies had a tendency to overheat and the desks were taken out of service after a few years.