Two years ago I wrote an article for Fusion under the heading ‘How many programmes?’ I ended that article by saying that it is most important that on a short-term basis everybody in the United Kingdom, wherever he may live, should be able to see the two main television programmes as soon as possible, and that, at all costs, we should avoid creating a badly planned chaos similar to that which exists in medium wave sound broadcasting.
I still believe we should aim at these two objectives. Further, I believe that if we are to succeed in avoiding technical chaos in television broadcasting, we cannot have additional programmes for another 10 years.
By international agreement the following wavebands are at present available for television broadcasting in Europe, including the United Kingdom:
|Band No.||Frequency mc/s||No. of channels|
|Band IV||470-585||23 (approx.)|
|Band V||610-960||70 (approx.)|
(Band II – 87.5-100 mc/s – is used for VHF sound broadcasting and provides about 100 channels if used with frequency modulation).
All five channels in Band I are used to distribute one BBC television programme which is available to about 98 per cent of the population. Four of the eight available Band III channels are used to distribute the ITA programme which is available to about 95 per cent of the population. The remaining four Band III channels allocated to television are used at the moment for various communication services but are being vacated and should soon become available for television.
There has been some talk about the possible extension of Band III to give facilities for additional television channels at the expense of other communication services. Such an extension of Band III would need International agreement, the likelihood of which appears remote at present.
Band IV and Band V channels – the UHF or ultra high frequency bands – are not yet used operationally in the United Kingdom but more than 100 transmitters in Europe and the U.S.A. use channels in these bands for television broadcasting. Receivers for UHF require somewhat more expensive valves and components than VHF – Bands I and III – receivers. The additional cost is likely to be about £5-£8 [£120-£190 now, allowing for inflation] for mass-produced UHF sets. An extra UHF aerial is also required costing between £2-£6 [£48-£143]. Most manufacturers in the United Kingdom would need a year or more to get into production of UHF receivers.
The desirable improvements which prompt us to reexamine the whole of the technique of television in the United Kingdom may be summarised under the following four headings:
Better definition of picture
Greater flexibility in world television exchanges
More channels for more programmes
The first two are inter-related. At present the United Kingdom operates on a 405-line system. If we adopted the 625-line system, programme exchanges would be possible with nearly the whole world, the main exceptions being North America and Japan (525 lines) and part of France (819 lines). Theoretically the 625-line system should give a picture with almost twice the definition of that received today in the United Kingdom. However, it must be remembered that in practice the 625-line system does not necessarily give the same improvement in quality in the home as one can get in the laboratory. This is because the higher definition system requires more careful maintenance of the transmitting and receiving equipment.
It should also be remembered when considering whether or not to adopt the 625-line system, that for the same cost in band width and at a lower capital expenditure, one could go to a 405-line colour system. Further, the adoption of 405-line colour would give a higher performance (inasmuch as colour adds to performance) while continuing to give compatible monochrome pictures at the present standard.
The addition of colour is an obvious development and would be welcome if the initial cost and the expense of maintenance can be brought down to reasonable levels.
The last point – more channels for more programmes – is an obvious requirement for a wider range and greater choice of programmes.
As things are at present it might be possible to squeeze one additional programme into Band III but this third programme would only be available to about 80 per cent of the population, mainly in thickly built-up areas, and would also limit the existing ITA programme to about 98 percent of the population, leaving about a million people with BBC programmes only.
Any additional programmes beyond the third would have to be transmitted in Band IV and V and unless these programmes are very attractive, the 80 per cent of the population who already have Band I and III receivers will not buy new sets to obtain Band IV and V facilities.
If it is thought that the required improvements in television services in the United Kingdom can be covered under the three headings of better definition, colour and more programmes, it seems quite clear that all these three are almost impossible to meet by utilising only Band I and III for television, a total of 13 channels for which sets in this country are equipped.
There are then three alternatives for future technical development:
- That by international agreement Band III and possibly Band I can be extended to give more channels. This, however, would be a very long international operation, the success of which is doubtful. Only a relatively small addition to existing sets would be needed for reception of the extra programmes, provided the 405-line system were maintained.
- If the extra channels under point 1 cannot be obtained, it would be necessary to use channels in Band IV and probably Band V if the three headings of better definition, colour and more programmes are to be achieved. This would necessitate new transmitters, receivers and aerials. But whether we adopt points 1 or 2 the technical effort involved in the change-over and an overlapping duplication – to enable programmes to be received on present receivers and which, therefore, would have to last for probably 10 years until they are replaced – would be so great that additional programmes would be out of the question until after the 10 years needed for this project to be completed.
- The alternative is to develop a system where more programmes can be squeezed into the present channel space and to introduce additional programmes, colour and higher definition at the same time as such a new system is brought into use.
I think that the desirable line of development is that outlined in point 3. The way in which this development could take place is for the four vacant television channels in Band III to be used to duplicate the BBC and ITA programmes through a new system to be developed which would include colour and higher definition. The next stage would be for preparations to be made for the introduction of additional programmes to be opened in 10 years time.
If the new system to be developed allows for twice as many channels as at present, then eventually we could either have a total of six programmes with the present coverage, or four or five programmes with really 100 per cent coverage of the country.
One cannot help but observe that as our various sound and television broadcast systems have been rushed into service without sufficient planning, we have technical systems which do not result in the best utilisation of the available resources.
It is thought that rather than rush in once again with higher definition and colour developments, it would be better to start out quite deliberately for the type of development that is mentioned above.
Only after such a system is successfully developed will it be possible to provide additional programmes, higher definition and colour within the limits set by the present international channel allocations.
The Times reported on March 17 Mr Hugh Carleton Greene, Director-General of the BBC, as saying that instead of the unallocated television channels in Band III being used for a third service, they would be better employed filing the gaps in both the BBC’s and ITV’s national coverage.
He is stated to have said that this would provide television to the one per cent of the population of the United Kingdom still outside the range of any transmitter. Thus there would be no need for Parliament to make a choice between the BBC and ITV and national coverage would be completed.
The consistency of his views and those expressed in the above article is interesting. — Editor.