Technology : Signals from Space

Clive Glover investigates the future of satellite radio in the UK

One section of the Government's Green Paper on radio suggested that the future could see the development of a Direct Broadcasting By Satellite (DBS) Radio Service for the UK. However, it completely failed to mention the more likely use of satellites — for distributing national or regional radio networks.

DBS television will shortly become a reality in Europe. Within the next year or so, DBS satellites will be launched for West Germany, France, Sweden and Luxembourg. Others -for Italy, Ireland and the UK — will be in orbit by the early 1990s. These satellites will broadcast TV directly to small (30-60cm) dish antennas placed on individual houses like existing TV aerials. Each satellite has four or five high-powered (250 watts) transponders — satellite jargon for channels. This means that each satellite is capable of transmitting four or five TV channels directly into homes across Europe. Luxembourg's satellite is different, with 16 lower powered (50 watts) transponders, which will therefore need a larger receiving dish.

CD Quality Radio

In theory, anyone of the TV transponders on one of these satellites could be used for radio, allowing perhaps twenty radio channels instead of just one TV channel (sounds a bargain!). So far, only the Germans plan to use a satellite and their TV-SAT will broad- cast 16-20 channels of digital (i.e. CD style, high quality) radio. So far, so good. However, the catch is that you will need some kind of receiving equipment for satellite radio as you do for TV — a dish on the roof, a decoder and an expensive Hi-Fi to make the most of the quality signals. It is unlikely that even the cleverest Japanese electronics companies will be able to produce a DBS car radio system for many years, let alone a portable radio or 'Walkman' for DBS. Even if they did, it would probably be so expensive as to ensure it would never become a mass-marketed product.

But do not despair I there is a much better way of using satellites for radio: distribution of networks. The French Telecom 1 satellite is already used extensively to distribute the new private radio networks, such as Skyrock and NRJ all over France at a fraction of the cost of building a complete network of terrestrial transmitters. There are also a number of networks covering the whole of the United States using satellites. Even the universities' radio stations have their own satellite transponder.

Glossary

DBS: Direct Broadcast by Satellite. More powerful transponders are used so that a much smaller satellite dish is needed to receive them.

DOWNLINK: The signals from the satellite, which you pick. up with your satellite dish.

SUB-BAND: An area of frequencies set aside for a particular purpose. e.g. Radio 1/2 between 88 and 90 on the VHF band.

TRANSPONDER: A device which takes one channel from the uplink and rebroadcasts it on another frequency.

UPLINK: The signal from the satellite earth station to the satellite transponders.

Network Radio

So, if you want to set up a complete national network, all you have to do is build a studio, rent a transponder and contract with British Telecom or Mercury to uplink your signals to the satellite. Then, you set up receiving stations which re-transmit the signal locally on VHF/FM in all the major population centres around the country: London, Birmingham, Manchester, Bristol, Glasgow... Only 20 to 25 stations will give you coverage of 65 to 70 percent of the UK's population. This way you can do without a whole sub-band of frequencies (like the existing BBC networks), without a vast and expensive network of land-Iines to carry the signals between transmitters, without huge, high powered transmitters outside the major cities (you can use small, low powered ones in the city centres — like the pirates) and without a vast engineering workforce -just a few people to maintain your studios and regional transmitters.

Commercial Suicide

Sounds wonderful doesn't it? Unfortunately, you can't actually do anything like this legally in the UK at present and the Green Paper didn't suggest it as a future possibility either. However, by the time the new Broadcasting Act is finally force in 1991/92, satellite distribution will be the normal way to do it throughout Europe and the idea of any any national networks being constructed in any other way will seem both old-fashioned and a sure route to commercial suicide.

In the next issue of Radio Today, I will look at existing and planned satellite networks In Europe and the USA which are or will be receivable in the UK whether the Government likes it or not!