My early days at TV Centre
by Dick McCarthy
I joined the BBC as an engineer in 1967, and after a few months in the
Studio Unit of SPID (Studio Planning and Installation Department), based at
Henry Wood House, transferred to Television Network department at TV Centre,
where I stayed for the next 33 years. I would like to share some of my
experiences of those early years with people, so that they can get some idea
of television operations in the late sixties and early seventies. It is not
intended to go into great technical detail, more to describe the different
areas that I worked in in my early years. Everything is based upon my
personal experiences, and what I can remember, and so if anything is left
out, it is probably because I didn't have a personal involvement.
I first became involved with TV Centre on my second day in the BBC, in
June 1967, as an engineer in SPID. I found myself in CAR (Central Apparatus
Room), working under the late Eric Taylor, having to equalise and time the
vision feeds for the new colour production studios TC6 & TC8. I suppose
because I had spent the previous 4 years working for Rediffusion
Engineering, in between going to college, I was deemed to be fully capable
of doing the job; and this was before going to Wood Norton! These were
exciting times. Colour television was starting on BBC2, and I well remember
getting distracted by watching the 1967 Wimbledon Tennis Outside Broadcast
on one of the Rank Bush Murphy colour monitors in CAR. I visited TC6, 7, & 8
CVAR (Combined Vision Apparatus Room), several times, to carry out
equalisation on the OS and output lines, using a pulse and bar test signal,
and a variable equaliser test set called a ’Fairy Fingers’. I then had to
work out the values of the components to construct fixed equalisers, and get
a wireman to build them, including winding the inductor coils. The CVAR was
designed for both 525 and 625 line working, as at the time of planning these
studios, there was no equipment available to carry out colour field store
standards conversion, so it was felt that the best solution, with an eye on
selling programmes to the States, was to have the means of originating in
525 NTSC, if required. Thus the CVAR contained both PAL and NTSC coders and
decoders, with EMI 2001 and Marconi MkVII cameras being able to work on 525,
as well as 625 lines. I do remember one programme originating from TC6 (or
was it TC8) in 525 NTSC, and that was the comedy, 'Charley’s Aunt'. This
must have been sometime in 1969, when the Advanced Field Store Colour
Converter, RD1, was available to convert from 525 NTSC to 625 PAL. Since
'Charley’s Aunt' was made to be shown both here and in the USA, in colour,
and no suitable converter existed to convert from 625 to 525, it had to be
made in 525, and converted via RD 1 for the home audience.
Another job I was given to do in CAR, was to replace all the valve
amplifiers in the studio vision outputs by new BBC transistorised ones, to
improve the performance of signals in the vision chain. After a couple of
other projects involving sending vision signals to Kensington House, via
Union House, on twisted audio pairs, using a balanced sending arrangement to
reduce crosstalk, and refurbishing the VIP Viewing System, which enabled me
to visit all the posh offices in the 6th floor Direction Suite of TV Centre,
I decided to transfer to Television Network and get involved in television
operations. To be honest, the true reason for the move was to work shift, as
I noticed the people on shift seemed to have every other day off. I started
off in Television Network in Presentation Studio A in early '68. The studio
had three EMI 201 vidicon cameras, with a valve vision mixer, and was
working on 405 lines. NC1 (Network Control Room 1) next door, also had valve
vision mixing equipment, and was also working on 405 lines. I became
immersed in the joys of ‘racking’ the cameras, for Promotions and Weather,
with the occasional ’Points of View’ presented by Robert Robinson. In those
days the Weather presenters only numbered 4, and were Bert Foord, Graham
Parker, George Luce, and Peter Walker. There were two permanent weather
charts in ’A’; one Atlantic, and one British Isles, with magnetic isobar
strips, which the weatherman had to stick on the charts before the
transmission or recording. It is taken for granted now that VT insert
machines run sync, but in those days sync working by Ampex VR1000 machines
depended on devices like Intersync and Amtec, and couldn’t be guaranteed.
Several times, just before a live trail, the Promotion Director had to be
told that the insert VT machine couldn’t run sync. This obviously ruined the
TX, as no studio captions could be superimposed over the VT replay.
Presentation studio B, next door, was working on 625 lines, and in
colour, with a mixture of 3 makes of colour camera. They were field testing
the relative merits of 3 and 4 tube cameras, to decide which colour cameras
should be used in the main production studios. The camera control units for
Pres B were housed in the NC2 Apparatus Room, which itself had its own claim
to fame. It was where the first video tape machines i.e. Ampex VR 1000' s,
were installed in TC before the VT area was established in the Basement. The
main output of' ‘B’ in those days was 'Late Night Line Up' or LNLU for
short, and this provided the early grounding in colour working for many
Network engineers, being the first studio in TV Centre to regularly produce
programmes in colour, until September 1967 when TC6 opened. I wasn’t allowed
to work in Pres B at this time, as I hadn’t yet been on the ETD colour
course (that came later in 1968). At the end of the 4th floor corridor, by
the main doors, a room was being constructed to become the CVAR for both
Pres A and B, as up to then the vision equipment was split between NC1 and
NC2 Apparatus Rooms. Previously, this room had housed a colour caption
scanner for BBC2 use, and a temporary home was found for it in CAR .
In March 1968, the decision was made to put NC I and Pres A on 625
pulses, even though the BBC1 service was still only 405 lines from TV
Centre. The reason for this was to ease the Network 1 operation, since a
large number of programmes were now only available on 625, including the
News up at Alexandra Palace, and any BBC1 programme originating on 625 lines
had to be first converted to 405 lines in the Standards Conversion Area,
before being handled by NC1 (when it was still working 405). This meant the
staff in Standards Conversion having to 'shadow' the NC1 operation. From the
date when NC1 worked 625 lines, any incoming programme on 405 lines, mainly
Regional material, had to be taken in emergency cut to bypass the NC1 vision
mixer. On the output of NC1 were two Line Store Standards Converters, SCV11
and 12, (main and reserve), which converted in the direction 625 to 405. If
6251ine signals were present on NC1's output, the Converter output was fed
to Network 1 distribution. If 405 line signals were present on NC1’s output,
the Converter was bypassed. This arrangement avoided the need for double
conversion when handling 405 line signals, apart from the fact there was
only one 405 to 625 Line Store Converter. An auto line standard sensing
device decided if the NC1 output should be converted or not. I remember at
least two occasions when this device malfunctioned, and decided to feed a
405 line signal via the Converter to line. BBC 1 viewers were treated to
what can only be described as an early form of scrambling! This hybrid
system lasted until November 1969 when the BBC 1 service went 625, (and
colour), and line store conversion then took place at the transmitting
stations to provide the 405 service to the VHF transmitters.
About June 1968, I was posted to CAR, where I had worked previously as an
SPID engineer. The CAR desk was manned (per shift)by two grade C, and two
grade D engineers, with two grade B1 Supervisors. The Supervisors shared a
small desk at the rear of the main desk, and reminded me of school, with the
teacher keeping an eye on his pupils. The bays in the apparatus area run the
length of CAR, with vision equipment on one side of the room, and sound
equipment on the other side. The sound bays were mostly packed with grey
painted valve amplifiers, such as C/9's and GPA's. The Main Routeing audio
and comms circuits were switched by Motor Uniselectors, installed late
1950's, and housed in their own room at the back of CAR. These were working
up to 1997, when they were removed, and the room used for the new encoding
equipment for digital television transmissions. Even some vision signals
were switched by mechanical switches at this time. Motorised wafer switches,
called Ledex switches, were used to route TK and VT vision signals to the
studio OS lines. All other vision routeing was carried out using BBC
designed relay matrices. The relay matrix was an improvement on the Ledex
switches, and not just in performance, as the latter could only route one
source to one destination. The relay matrix did, however, have the drawback
of requiring the use of a soldering iron to change the input and output
amplifiers, or replace a relay strip; not a simple card change. Test Cards
were generated using a mixture of Monoscopes (a type of camera tube with a
test pattern etched on the target), and Transparency Scanners. One of the
main duties of the CAR vision engineer every morning was to line-up the Test
Card Scanners for Test Cards C, D, and F, as they appeared on-air a lot more
frequently in those days; in fact a large part of the BBC2 daytime schedule
consisted of Test Card F. The News was still at Alexandra Palace then, and
before a News studio could go on-air via NC1 or NC2, the source (a vision
and sound circuit from AP), had to be selected by CAR staff to the booked BH
to TC vision and sound circuit, by remotely controlling a matrix at BH
Switching Centre. It wasn’t possible to quickly cut to a News studio, as is
done today. At that time CAR had to handle a mixture of 405 lines, and 625
line monochrome and colour signals. There were 405, 525, and 625 line pulse
chains, with elaborate techniques for source synchronisation. There were no
digital synchronisers then, and the main method of making OB's or Regions
sync into a studio was to use a pulse locking system i.e. genlock or
slavelock. The alternative was to use an optical standards converter, but
more about that later. It should be pointed out that OB's and Regions were
normally only picture phased into Network, (to avoid a frame roll during the
cut), and were not sync. This was the era of CLNGS (Constant Line Number
Generator Synchroniser), often referred to as 'Willie Nobles', after its
designer, and these devices compared local and remote sync pulses, modifying
a twice line frequency signal to a local SPG, in the case of genlock, or to
a remote SPG, in the case of slavelock. Locking could take up to 30 seconds,
depending on the picture phase difference between local and remote signals,
but could be speeded up by initially picture phasing before locking. Since
405 line signals were mains locked, (to reduce the visibility of hum on some
receivers), a piece of equipment called a Goniometer was used to shift the
phase of a mains reference into the CLNGS, and hence move the SPG timing
relative to other SPG's locked to mains.625 line SPG's were crystal locked,
and a variable divider unit was used to achieve picture phasing. The two
master chains, 4A for 405, and 6A for 625, were not subject to any timing
change. At this time, because of the introduction of colour, a new system of
pulse locking had also come into service, known as Natlock, short for
National Slavelock, and this became the accepted method of achieving source
synchronisation for many years until the digital synchroniser came on the
scene around the late 70's. The Natlock system relied upon the use of audio
tones to convey error signals for sync timing and colour phase, from CAR
back to an OB or Region. A telephone control line (with no Ringers) was
required to convey these tones, and during the line-up of each OB or Region,
it was necessary to equalise this control circuit to ensure it could carry a
range of 7 different tones, each representing a different error signal. The
time taken to carry out this equalisation, apart from checking all the other
signals from the source, and a wait of up to 4 minutes for full colour lock
to be achieved, meant that some OB's were not sync until seconds before
being on-air. No instant sychronisation in those days. A refinement of this
system, that came later, was Icelock, whereby the error signals were sent as
digital signals in the Network signal Vertical Blanking Interval, and
Regions and OB's used BBC1 or 2 signals to receive the Natlock errors. It
didn’t always work well if the OB had poor BBC1 or 2 reception from their
Check Receivers. There was in fact a distance limitation on Natlock, the
loop delay had to be less than a certain figure, or else satisfactory lock
couldn't be achieved. I think that whenever we slavelocked Aberdeen to
London, it was always touch and go.
A few weeks later, I moved upstairs to the Standards Conversion Area
where equipment existed for changing the line and field frequency of signals
between the four standards in use at that time i.e. 819, 625, 525,and 405
line. There was a mixture of optical and electronic converters, and the
whole area was very spacious. There was even an 819 line test generator for
checking equipment involved in 819 line conversions, although I think these
were rare. The optical converters were no more than a TV camera looking at a
high quality monitor, but obviously refined to minimise the various defects
that the conversion process introduced, particularly when converting between
different field rates. There were three basic types according to the type of
camera tube used i.e. CPS Emitron, Image Orthicon, and Vidicon, and all
required a great deal of skill to produce acceptable results. I certainly
remember converting some 'Forsyte Saga' episodes from 625 to 525, using the
Fernseh Vidicon converters, and carrying out 405 to 405, and 625 to 625
synchronisation (an alternative to pulse locking), on the Image Orthicon
converters. Because the CPS Emitron and Vidicon converters could handle 525
lines, they could be powered from 60Hz mains obtained from rotary
converters. There were also several electronic converters, and most of these
were the Line Store Standards Converters, designed by the. BBC, and used
mainly to convert from 625 lines to 405 lines. Two of these were permanently
tied to NC l' s output, as mentioned earlier, with a third as a spare. The
remaining two Line Stores were used for general programme conversion. One
for 625 to 405, and one for 405 to 625. Since at this time, most, if not
all, the Regions were still working on 405 lines, the daily News feed from
Alexandra Palace, on 625 lines, to the Regions, as part of their evening
opt-out programme, had to be brought into TC for conversion to 405 lines
before being fed out again to wherever it had to go. All the foregoing
equipment could only handle monochrome signals. With the start of the colour
service, there was a requirement to be able to convert between 525 and 625
in colour.
To enable this, Design's Department built two simple converters, known as
DD1 and DD2. These were three bays of equipment each, and converted in one
direction only. DD1 did 525 NTSC to 625 PAL, and DD2 did 625 PAL to 525
NTSC. They used ultrasonic quartz delays to store a complete incoming field,
(hence they were called Field Store Converters), and an oven was used to
keep the quartz delay sections at a precise temperature to ensure the delay
remained the same. It was the job of the early engineer in the area to use a
resistance box, as part of an impedance bridge, to measure the oven
temperature, and adjust for any drift. These two converters, however, had
two drawbacks. When converting from 525 to 625, a 525 line picture was
fitted into a 625 line raster, and with a corrected aspect ratio, it
appeared as a smaller picture bordered like a postage stamp, although
nothing was lost. I remember the Continuity Announcer having to apologise
for the small picture every time DD1 was used on-air. This converter was
used. to convert the early 'Rowan and Martin's Laugh In' programmes that
went out in those days on BBC2. Although British viewers never saw the
output of DD2, this converter actually lost picture information, as it was
fitting part of a 625 line picture into a 525 line raster and with the
corrected aspect ratio, appeared like a zoomed in picture. The other problem
with these DD Converters was that two PAL or NTSC outputs existed. One with
the right colour subcarrier frequency, but not locked to line syncs, and one
with the wrong colour sub carrier frequency, but locked to line syncs. The
former was referred to as the Transmission output, and the latter, as the
Record output. It came about because 525 NTSC field frequency was not 60Hz,
but 59.94 Hz. The DD converters used a rigid 5 to 6, or 6 to 5, ratio when
converting the field frequency, and this resulted in the subcarrier, line,
and field frequencies being 0.1% low, in the 525 to 625 direction, but 0.1%
high in the opposite direction. This meant that both Transmission and Record
PAL and NTSC decoders existed for monitoring. The Record output was suitable
for later transmission, once recorded, as on a VT replay locked to station
pulses, the standard frequencies were produced. Having two outputs from DD2
gave rise to problems when feeding the converter to the USA, which was most
nights with News material from the three main American broadcasters, ABC,
CBS, and NBC, based in London. All the material was on film, but there was
only one Telecine machine that could work 525, so most feeds needed to be
converted when 625 Telecine machines were used. Initially, the converted
feed sent depended on if they were transmitting live or recording, but the
problem was solved by feeding the Record output to the States, and getting
the US broadcasters, to carry out an NTSC decode/recode to provide a signal
suitable for live transmissions. There were also a couple of SECAM to PAL
transcoders in the area to handle the occasional SECAM signals from France
or Eastern Europe.
All this changed in the latter part of 1968, when Research Department
staff arrived to install RD1, the Advanced Field Store Colour Converter. It
was 7 bays long, and was installed in place of the CPS Emitron converters.
It only converted from 525 to 625, but was a big improvement, as it gave
full picture size, a standard PAL output, and was a synchronous source. It's
only competitor was a Bosch colour optical converter, using three cameras,
and in use by some broadcasters. RD1 spelled the end of DD1, and made its
debut in converting the 1968 Mexico Olympics from 525 to 625, in colour, for
28 broadcasting organisations around the world. When the Olympics started, I
was busy providing an optical back-up, on the Fernseh converters, just in
case RD1 failed, when in walked James Redmond, the then Director of
Engineering, asking how things were going! Converter DD2 was still used,
however, to provide outgoing feeds to the States, but was replaced about
June 1969 by converter RD2. This was very similar to RD1, but converted from
625 to 525, and made its debut in feeding pictures from the Prince of
Wales's Investiture at Caernarvon Castle, to a 525 audience. Following this,
RD2 was dismantled, and returned to Kingswood Warren for modification to
provide additional 625 to 625 synchronisation facilities. It re-appeared in
the Standards Conversion Area in early 1970. As a synchroniser, it provided
the world's first electronic means of synchronising colour pictures, and was
the first ‘instant' synchroniser. The 'Grandstand’ programme made full use
of it, and I can recall a particular Saturday when Lime Grove Studio E, the
'Grandstand' studio, was synchronous into Cardiff, simultaneously with
Cardiff synchronous into 'E'. This could never have been done before using
just pulse locking techniques. A modification was also made to RD2 to enable
it to synchronise SECAM signals, prior to being fed to the SECAM to PAL
transcoders. This overcame a problem in the transcoders, which like DD1 and
DD2, had both a Transmission and Record PAL output, because of the ‘looser’
spec of SECAM signals compared to PAL. Without doubt, my most memorable
experience was the night of the moon landing in July 1969. I was on duty in
the Standards Conversion Area, and RD1 was being used to convert the
incoming 525 pictures to feed many parts of the world. The announcement was
made that ‘The Eagle has landed’. All hell broke loose. Everyone in the
world wanted to feed to the States with their congratulations, and so RD2,
and the two Vidicon opticals, were kept busy converting the incoming 625
pictures to 525. I was still lining up one of the optical converters when
the Prime Minister, Harold Wilson, appeared on the screen, live from Downing
St. One incident sticks in my mind for this event. It was usual to complete
a programme log for all conversions, showing the source and destination. One
of my colleagues entered the source as 'The Moon'. Can this ever be beaten?
Looking back over the years, I feel I was fortunate to be around when so
many developments in television broadcasting took place.
Dick McCarthy
August 2010
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