To the North 

10 May 2021 tbs.pm/72829

THE INDEPENDENT TV NETWORK

How the Post Office is Helping to Build up the ITA Service

 

 

Television Annual cover

From The Television Annual for 1957, published in late 1956

AN elaborate network of vision and sound circuits has been set up by the Post Office to enable the ITA to operate its independent television service. This network is routed through the main Post Office repeater stations, and links the ITA transmitters at London, Lichfield and Winter Hill (Lancashire) to the various contractors.

Vision and sound circuits in the London network radiate from the Post Office Television Control at the Museum Telephone Exchange near Tottenham Court Road. Television House in Kingsway, which accommodates the master control of Associated-Rediffusion Ltd. and also Independent Television News, is linked by two balanced cables to Museum, yielding ten vision circuits.

The master control of Associated TeleVision Ltd, at Foley Street, is linked by two coaxial cables to Museum Exchange, yielding eight vision circuits. Further vision circuits link Museum Exchange to the London ITA transmitter and to a number of London studios and theatres, some as far distant as Wembley. Vision circuits have also been provided to sites on high ground at Kensington and Highgate, which serve as radio reception points for the longer-distance outside broadcasts.

The extension of the independent television service to Birmingham necessitated the provision of vision and sound circuits from London to the Post Office Television Control at Telephone House, Birmingham. This in turn was extended to the new transmitter at Lichfield, and to the master control of the two programme companies at the Astoria Cinema, Aston. The London-Birmingham vision link consists of a two-way radio circuit, and is being reinforced by the addition of a second vision circuit working in the north-going direction. The second circuit will cover the distance in four hops, using three intermediate relay stations. The vision link to the Lichfield transmitter also provides a two-way circuit.

 

A diagram showing links between London, Birmingham and Manchester, the studio centres, and the transmitters

 

The extension of the new network to Lancashire involved the provision by the Post Office of a two-way vision link between Telephone House, Birmingham, and Telephone House, Manchester. The signals are amplified at approximately six-mile intervals between Birmingham and Manchester.

The two Manchester programme contractors, Granada Television Network Ltd. on weekdays, and Associated British Cinemas (Television) Ltd. at weekends, have established independent master controls at Quay Street and the Capitol Cinema, Didsbury, respectively. Each master control in linked to Telephone House by vision and sound circuits.

 

The following section is commentary from Transdiffusion's expert writers

Kif Bowden-Smith writes: This article, which has been simplified for the layman, shows just how complicated the ITA’s television service was. In many countries, the transmitters opened and only later, sometimes many years later, was thought given to networking – and even then it was usually from a central point to a distant affiliate with no facilities to send pictures and sound back.

But the ITA’s young network was designed from the beginning for competition between, at the very least, the four contractors operating in the three major regions of England. They would need to not only take pictures from a central hub – London – but also send pictures back. And they would need to have the ability to send something to only one of the other contractors allowing another to opt out, so that, say, Granada could send a programme to be seen live on Associated-Rediffusion without ATV Midlands having to take it; meanwhile, A-R in London could be sending a programme on delay for ATV Midlands to show in place of the Granada programme.

 

A map of the UK, showing the three English TV regions

These are the areas (including the so-called “fringe” areas) which have been covered by ITA transmitters up to the autumn of 1956. The new Scottish station is planned to start operating during 1957, with its transmitter in the Kirk O’ Shotts area.

 

This infrastructure had to be built in parallel with the first 4 transmitters, which required the ITA and the Post Office to think carefully about where to put their transmitters to maximise coverage of a region whilst also making sure each transmitter could be linked to the Post Office’s network by a reasonable and cheap route.

To rewind time, this meant that extensive surveys of each region had to be done to find an ideal site. Once the options were narrowed down, tests were needed to ensure that there were no pockets of poor reception in unexpected places – the idea of co-siting of the Northern region transmitter with the BBC’s pan-north mast at Holme Moss was abandoned early on for many reasons, one of them being that it left Liverpool, a good 30% of the potential income base for the new contractors, terrifyingly near the edge of reasonable reception.

 

ABC Weekend TV’s earliest daily start-up routine.

 

These tests were done by the use of transmitters in a caravan attached to an aerial on a balloon (later the ITA would invest in a ‘zip-up’ temporary transmitter on the back of a lorry), and Post Office vans drove around the area checking reception; to make doubly sure they were sampling everywhere, radio hams (amateur radio broadcasters and listeners, also licenced by the Post Office) were asked to tune in and report reception back using the QSL postcard system that was already in use between amateurs and between long-distance reception enthusiasts (DXers) and shortwave radio stations. Once all the data was in and analysed, it was then possible to find a single site to start building a mast.

 

A recreation of ABC Weekend TV’s 1956 ident by Dave Jeffery.

 

Once the mast was built, more testing was required – not just of the location but also of the aerial equipment itself. A failure to do this early enough leads to unexpected results; the Scottish Television transmitter at Black Hill worked perfectly in the lab, but once the aerial was hoisted into place on the mast, it was discovered that an odd interaction between the aerial and the mast itself produced a signal that was polarised incorrectly and service pattern far different from that intended. The mast had to be expensively replaced quite quickly.

 

G9AED test card

From ‘Practical Television’, May 1956

 

The tests were done using a portable transmitter, under the Post Office licence of G9AED (the last three letters were assigned in order of applications, so mean nothing), attached to the aerial on the newly built mast, whilst the transmitter equipment was being installed in the buildings below.

These tests, which were only done this way for the main transmitters and not for later booster and in-fill sites, consisted of a mixture of sound-only, vision-only and sound-and-vision broadcasts. Sometimes there was no picture, but a range of tones could be heard. Sometimes it was a test card with a request that dealers seeing it report reception difficulties back. Sometimes it was recorded announcements.

 

A recreation of Granada TV’s daily start-up sequence from 1958 by Dave Jeffery.

 

At other times, a neighbouring region was output in short bursts, often less than an hour. Even then, the handover announcement at the start of programmes, mentioning the broadcaster and the original transmitter or channel number were not carried. The service was also blanked when the adverts came on, as G9AED, and indeed the new permanent transmitter that would succeed it, were not yet licensed to carry commercials. I saw this process twice: once on holiday in Newquay in 1961, where I watched Southern Television go out on what would, days later, become Westward Television, and at home at the end of 1962 where the new Moel-y-Parc transmitter carried bursts of Granada’s output in the run up to the opening of Wales (West and North) Television on that transmitter.

With thanks to Darren Brian Renforth

You Say

2 responses to this article

Pete Singleton 11 May 2021 at 10:20 pm

Dave Jeffery’s superb recreation of the Granada start-up sequence just brings back so many memories. Even though this piece is no longer heard, I can hum every single bit of the tune as though I only heard it today at 4.45 pm! Such is the impression this made on me at the time. I do SO miss start-ups!

Leonard Carghill 14 May 2021 at 6:16 am

What frequencies were, (or even just frequency band was) used by the General Post Office for the radio circuit links?

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