The Death of 405 Line Television in the UK
As reported by IBA "Engineering Announcements"
|The 405 line system was invented 50 years ago on a Sunday morning in
1934. This was in the home of the electronics genius Alan Dower Blumlein,
a member of the EMI Research Team led by Sir Isaac Shoenberg. The first
experimental television transmissions were on John Logie Bairds 30 line
system, later updated to 240 lines.
But the rotating mechanical drums and mirrors could not compete with the lightweight all electronic system developed by EMI. The BBC began regular programmes in November 1936, broadcast from Alexandra Palace, Channel 1 in VHF Band I. The Baird system was finally abandoned some three months later.
|It was in 1954 that Parliament passed the Television Act that established the Independent Television Authority. By then, VHF Band I was fully occupied by BBC transmissions. The ITA had to build up coverage in a new and previously unused part of the VHF broadcast spectrum, Band III. In 1955 the BBC moved their transmitter to Crystal Palace in South-East London and the ITA decided their first station should be nearby.|
|On a site on West Norwood Hill in Croydon, the temporary station used a single
laboratory prototype transmitter on Channel 9. The ERP, initially 60KW from a 200 foot
mast, sufficient to give good coverage over a wide area.
After just nine months of hectic preparation, regular test transmissions began on 13th Sept 1955. Programmes began on the 22nd September.
|Five months later the second ITA transmitter came on air, Lichfield, serving the
midlands. Much of the original equipment is still there, although the present mast and
aerial were brought in to service in 1961.
At the transmitter right from the start was Bill Arnold. What were the early days like?
|"Well we had quite a hectic run up over the Christmas
period, the staff were here from about the 1st December when there was no roof on this
section of the building and in fact we started life in the Pantry, and we helped Pye put
the place together in a short six week period had the transmitters in and working
only one set of transmitters for opening day.
There was quite a rush to get on the air the building had not even been started until the previous June."
|Now this equipment dates from that time it is in remarkably good condition. It
is now being made obsolete? Are you going to be sorry to see it go?
"Yes naturally , although we do have plenty of other work to do and the maintenance load that this presents we could well do without. Its getting very old and an awful lot of the components now are unobtainable such as the valves."
|What is going to happen to this equipment?
"Well this equipment unfortunately will be carted out of the door and scrapped. It has no use for anyone else. We have been fortunate that on some of the more recent equipment of being able to give it to hospitals and the like for further use. At this age, the equipment is not fit for much further use."
Can you tell me about some of the things that have happened at this transmitter site, for example problems with the weather?
|"Fortunately we are fairly close to the A5 so the worst we have to do is walk in from the bottom of the road. This was much more critical in the days when we switched It on first thing in the morning and switched off last thing at night and had an evening shift here. These days television in general is fully automatic but in those days we used to have to walk in and start up extra early if the weather was bad in order to switch on in time for the morning test card. I dont think we ever missed it, but one Boxing Day morning a main transformer blew up and there was a wind that something wasn;t quite right and one engineer walked in five miles across a field through the snow."|
|"We have had exciting times here on a number of open days, we had about four in all, the most successful we had 10,000 people walking through this very spot to see what we did.. There was real magic in television in those days. For example the equivalent of todays domestic video recorder would have taken up a whole room in those days, it is amazing how much we have some on."|
|Do you think it is a bit sad that television is not so much of a novelty today and
that people are not quite as fascinated as they were then?
"Naturally I do, I still find theatre as a novelty against cinema, because of the discrete performance, and the fact that we switched it on every day we seemed to have a much greater personal interest in everything that goes on. Although we have nothing to do with the programming, we had a great affinity for those that did. In fact Noele Gordon came here and had tea here in the days of "Tea with Noele Gordon", and that dates one because that was 1956/57."
|In 1969, all ITV studios switched over to 625 line production. Standards convertors were installed at the transmitters, each one using more than 2000 transistors. The 405 line network had been extended to 47 transmitters covering 98.7% of the population. But the start of colour on UHF in 1969 signalled the eventual demise of the 405 system. But even though UHF coverage is now up to 99.5%, what about the few who still watch 405? Brian Rhodes:|
|"We have had very few letters, I dont think we have had ten letter I think. We have been telling them that 405 line is being switched off since about September."|
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Last Updated 01 Apr 98