Memories of Designs Department from 1970 to 1985
The picture shows me
demonstrating the Silver Streak Transposer at a Designs Department Exhibition in
I think that this was the Department's only full scale exhibition involving all
of the Sections, and it was a great success.
It was held in the Langham (now The Langham Hotel), just across the road from
After three years at
Daventry transmitting station, I joined Designs Department as a Laboratory
Technician in 1970 and left in 1985 when I was Head of Transmission Section.
Johnny Johnstone was on my interview board and he gave me the opportunity to
join the Department. I worked in RF Section for several years under Johnny’s
inspirational leadership and I remain extremely grateful to him for the
encouragement and guidance he gave me. After leaving Designs Department he
academic at the University of Surrey, but he always had professorial
tendencies. On many occasions he approached me in the laboratory to discuss my
project and he filled sheets of paper with almost indecipherable mathematics.
Handwriting was not his strong point, but his engineering and mathematical
guidance was well worth studying, which I usually did when I got home. This was
undoubtedly good for me professionally, but sometimes I couldn’t take in any
more and tried to discourage Johnny’s visits in the laboratory by barricading
myself in with large quantities of test equipment on trolleys!
Johnny did particularly
well at securing funds for radio frequency test equipment (which was very
expensive) and by the late 1970s the RF laboratory was an Aladdin's Cave with
all sorts of wonderful pieces of technology such as spectrum analysers, network
analyers, modulation analysers, tracking generators, power meters, frequency
synthesisers etc. However there was only one spectrum analyser which we had to
fight over when I first started there and the only calculator was a large
Computer Aided Design
RF design engineering in
those days tended to be something of an art, because the tools were not
available to provide precise modelling of components at the high frequencies
involved. On the other hand, the theoretical calculations involved with
designing filters and matching circuits etc are very complex. I was
particularly keen on using computers to minimise the uncertainties and I think I
was amongst the first in the Department to do so. I was not clever enough to
write the programs that manipulated S-Parameter matricies etc. but this was done
by David Boughton, a very good mathematician who set up the Department’s
Computer Unit. My role was to use these programs to calculate and optimise
component values, including the dimensions of transmission lines fabricated on
special printed circuit boards made with low loss dielectric that had a well
defined dielectric constant.
One of my first designs
was a frequency synthesiser for use in a TV transposer that was nicknamed the
"wine press" because of the way that all the RF modules were clamped together.
I think it was the first RF frequency synthesiser in the BBC and Johnny
that I should present a paper on it at the Institution of Electrical Engineers.
I was only 23 at the time and in awe of the achievements made by other engineers
working in the same field, so it was with great trepidation that I stood on the
stage at Savoy Place in front of a couple of hundred people, with a portrait of
Faraday looking down on me. However I got through it and was grateful to
for giving me the experience.
Blue Streak Transposer
promotion to Design Engineer I worked in the “Blue Streak” transposer team led
by a very nice chap called Stan Collier. When these transposers started to go
into service, Stan took the whole team for tea with the BBC’s Director of
Engineering who, along with HDD
and others, thanked us all for the work that we had done. This fairly
unusual event was much appreciated and undoubtedly influenced my management
style in later years. The Blue Streak looked very strange and was made with
several, specially designed, cast aluminium boxes bolted onto a vertical metal
sheet. They were all blue hence the name, coined by someone from Transmitter
Department. I think that it was the World’s first UHF TV transposer to use
broadband modules that could be set to transpose between any of the required
channels simply by connecting them to passive components that set the
frequencies. This had significant operational advantages and proved to be very
reliable. In fact I believe that about 600 were still in use some 30 years
later. I designed the 50dB gain, 2Watt power amplifier, but even though I used
state of the art transistors in the output stage they only gave about 3dB gain
which is very poor, but it was an interesting challenge to get the most out of
available technology. I enjoyed using Smith Charts (see picture) and computer
aided design during this project. I hope that John Sykes will
describe his frequency synthesiser design for the Blue Streak because it was a
very imaginative and well executed piece of work.
RF Test Set
Meanwhile, Robin Caine was
leading another team in RF Section that designed a “Comprehensive RF Test Set”.
It was an amazing design that
greatly reduced the amount of equipment that the BBC’s transmitter maintenance
teams needed to take to transmitter sites. The problem for me was that by the
time I joined the project most of the other modules had been designed and the
estimate I’d given for the space I needed was too optimistic. My earlier
frequency synthesiser work put me in line to design the synthesiser for the RF
Test Set, but this time it was much more difficult, due to higher frequencies
(up to 1.4GHz), temperature range requirements and lack of space. I found it
particularly difficult to get the phase noise low enough and it was never really
satisfactory. I worked long and hard trying to get it right and all my
colleagues were very helpful and supportive, in particular Laboratory Technician
Steve Bowling who did a great job and was very patient with me. I really suffered on
this project and I was not proud of the end product. The maintenance teams
had to put up with my synthesiser until Bill Murray designed a
replacement several years later, allowing the Test Set’s many good features to
come to the fore. Bill had the benefit of new components, but success was
mainly down to his design ingenuity.
PCM Test Generator
needed a change and moved to Transmission Section where I thoroughly enjoyed
designing the Department’s first digital test generator in 1976 (GE7/1, see
picture). It simulated a PCM coder, producing precisely defined waveforms that
were used to align the PCM decoders at the main FM transmitting stations.
Entirely made from digital logic, it was a refreshing change from RF. Once
again, it had to fit it in a small space and this was achieved through the
expertise of Laboratory Technician Neale Davison.
In 1976 I was asked to investigate a problem
with new cameras being used by BBC Outside Broadcasts and I found that picture
defects were being caused by impedance mismatch problems. While
investigating, I had to almost completely disassemble one of their brand new and
very precious cameras, to get at the interface for the camera's triaxial cable.
I am no stranger to taking things to pieces, but I was very relieved when
I got it back together and working again. During another project for OB's
(feasibility study for a new communications system), I spent a
day with the OB crew at Ascot, so I put a bet on at lunchtime and my horse came
in at 5 to 1. A profitable job!
Around this time I got
involved with seminars that the Department put on for various groups of visitors
and I devised a party piece that demonstrated several of the Section’s
achievements. I used the “Carrier Equipment” to frequency division multiplex a
13 Channel PCM coder and baseband video with Sound-in-Syncs, then I passed the
whole signal through an almost invisible optical fibre. I proved that I was not
cheating by pulling out the fibre to stop all the sound and picture. Optical
fibres were fairly new in 1977 so this created quite a lot of interest.
Microprocessors were just
beginning to appear and Richard Russell of Monitoring & Control Section
produced the first working design that most of us had seen. The Department
benefited greatly from the enthusiasm of staff who developed expertise working
on their own personal projects outside work, and this was a prime example. I
was so impressed that, as a small official project, I built a demonstration
microcomputer based on Richard’s design and helped a number of people in the
Department to understand the basics.
Trips around the UK
For some years I had been
envious of the people working in Monitoring & Control Section, so I was
delighted when I managed promotion into the section as a Senior Design
Engineer. They were a very clever lot and their strongly held views made life
fairly dramatic at times. The other, far more experienced, Senior Design
Engineer was David Carter and he was leading pioneering work on the development
of Monitoring & Information Centres (for the transmitter network). I did
various fairly small projects including a unit (CO8/5) that would fit into any
of the Automatic Fault Reporters installed at transmitting stations, and it
enabled measurements of signal quality to be signalled back to headquarters.
Designs Department, in particular David Savage, had done a lot of work to
establish satisfactory picture quality throughout long and complex distribution
paths, but station visits to check for variations over time were expensive and
time consuming. By fitting my unit at the ends of major chains it was possible
to track any performance variations more easily. The benefit for me was
visiting, Shetland, Isle of Lewis, Northern Ireland, Wales, Devon and Jersey to
install the units and make tests. These trips in 1978/9, with Tim Cook of
Transmitter Department for guidance, were most enjoyable.
After quite a struggle, I
felt that I was beginning to be accepted in M&C Section. Then one day I
was called to see my Group Head David Kitson and Johnny Johnstone. Following the
success of Blue Streak there was a requirement to design a successor and they
asked me if I would be willing to lead the project. Having previously done a
long stint in RF, really I wanted to move on, so I said no thank you. I knew
that I was pushing my luck and I felt rather bad about it after all the
mentoring I had received. So, the next day when Johnny had a quiet chat with me
I changed my mind. In fact David was offering me a marvellous job and it was
foolish of me to be difficult about it.
I knew exactly who I wanted on
the team and I got them all. Rhys Lewis designed the IF unit and Bill
designed the frequency synthesiser. Jack Hart designed the physical housing in
conjunction with people from Services Section,
including a special aluminium extrusion (see picture). He also designed the
comb line filters with consultancy from John Sykes (who was leading a very
successful VHF/FM transmitter project at the time). Other engineers,
technicians, drawing office and model shop staff joined the team when
necessary. They were all first rate and the end result, in 1981, was very
good. Compared with the successful Blue Streak, this new “Silver Streak” transposer had to be better than half the cost, half the size and half the
weight. This was achieved by a significant margin and it was far more flexible
operationally. I believe that about 750 were still in use some 25 years later.
HF Control System
Meanwhile, back in
Monitoring & Control Section, David Carter had developed a leading-edge
distributed microcomputer architecture for the control system of a big HF
transmitting station at Woofferton. His team included Richard Russell, David King, Nick
Cutmore and John Went, who also contributed a great deal to this very
I moved back to Monitoring
and Control Section and my job was to lead the team to automate the control
system at the Skelton HF transmitting station. In some ways my job was easy
because the basic design had been done for Woofferton, but it was quite
educational from a management perspective. I didn’t know nearly as much as the
others about the intricacies of the microcomputer system, but I tried hard to
reconcile all the strongly held views and it was very satisfying to see the team
achieve another conspicuous success.
In 1983 John O'Clarey, the
Head of Transmission Section retired and I replaced him. The section was doing
all sorts of interesting work including NICAM, Dual Channel Sound-in-Syncs,
68PAL and digital OB multiplex.
Robin Caine was the
leading light on Designs Department’s development of
NICAM, but it was David
Savage who invented this acronym, which later became well known to the general
public. It stands for Near Instaneously Companded Audio Multiplex and
originally referred to a system used for internal contribution and distribution
circuits. A variant with more error protection and a slightly higher bitrate
was developed by BBC Research Department for broadcasting stereo sound with
television and it is this system that made NICAM so well known.
Dual Channel Sound in
Syncs also used NICAM coding and for this project we pioneered the use of ASICs
(Application Specific Integrated Circuits) in Designs Department. After
investigating several possible suppliers we selected LSI Logic and Duncan
Nightingale did a splendid design job, under the guidance of John Robinson.
Digital video coding has
come a long way in 20 years, but in 1984 it was quite an achievement to reduce
the bitrate to 34Mbit/s and retain broadcast quality. In partnership with
Research Department, 68PAL was developed in Transmission Section by Rhys Lewis and David Birt.
Owen Cullum, a young
engineer who was studying digital filter techniques at college, used his new
found expertise to develop a replacement for an old and very useful design for
Outside Broadcasts. It enabled up to five low bandwidth audio channels to be
sent over a single music circuit, using frequency division multiplex. The
original design was full of inductors and capacitors, but Owen’s design used
analogue/digital conversion with all the processing carried out in the digital
I felt that I had “made
it” when I became a Section Head, but it marked a transition away from
engineering and towards management. This was good for my career, but I missed
being able to get deeply involved in technical detail. In 1985 I was invited to
join Communications Department and subsequently became Head/Director of
that in the BBC and Crown Castle, but I am an engineer at heart and often
yearned to be back in Designs Department. However "Black Spot" happened
soon after I left, which is another story......
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