AM or Medium Wave was invented in the 1920s. Many will have heard grandfathers recall the excitement of making crystal sets to receive early broadcasts pioneered by enthusiasts. 2LO was one of the leading broadcasters to emerge which later formed the BBC. News reports on developments in World War 2 were just one of the factors that made radio an essential part of daily life. Early British drama and comedy is still much revered today and the BBC has been largely responsible for creating a wealth of musical talent from the big bands to pop stars ever since.

Grandfathers scoffed as crystal sets were replaced by valves. Then with the emergence of television in the 30s, critics said "radio was dead". Nonetheless, radio had already become too important a part of life for a generation to quit the habit! Rather than die, radio blossomed - helped by its portability. Radio operators were concerned, though, that the UHF channels used by television provided better sound quality than AM radio broadcasts. As a result, FM radio was invented during the 40s although transmission of FM on VHF channels did not become commonplace until the late 50s.

The fact that a radio set could be unplugged and carried to work or to a friend's home and plugged in there had always been an advantage over early TV. However, the big break really came with the silicon chip or, should we say, the early transistors. Another generation scoffed at the tinny sound of transistors by comparison. Yet, over a decade, the benefits of transistors became recognised and it was realised that the quality was actually far superior where decent loudspeakers were actually utilised. More importantly, though, a transistor radio could be operated by batteries adding to its portability.

At around about the same time a famous radio station in Luxembourg started playing something called rock 'n' roll and pop music. A generation of younger radio fans was born. This was followed in the early 60s by a further surge of the new pop culture broadcast by the pop radio pirates such as Big L and Radio Caroline. The BBC and the government came to recognise that pop was also here to stay. As a result Radio One was born in 1967 followed by the first 16 commercial radio stations in 1973.

By the mid 80s the majority of radio listening had transferred to FM and stereo broadcasts were commonplace bringing about a boom in the hi-fi retail sector. During the 80s yet another generation scoffed at the birth of the CD and digital audio. Just over ten years later, try buying vinyl! The CD has brought about a demand for the highest quality sound. Yet radio broadcasters are still transmitting a technology which is, at least, 70 years old. The 90s has also seem the emergence of digital sound sampling on PC computers and the advent of a new form of entertainment provided by the internet. The human race never tires of wanting more entertainment and an easier lifestyle!

1998 has brought about an overdue need for radio to evolve once again. There are now more than 200 commercial radio stations in the UK and the BBC has expanded too. Frequency spectrum on FM has simply become 'clogged up' and finding alternatives has also been a further important factor pushing development. The new radio revolution is about to happen for another new generation of radio listeners seeking digital sound quality, multimedia accessibility but with the same portability as traditional radio. In a nutshell, the time is right for DAB. The audience demands it and the technology is ready.

The almost universally accepted DAB standard has been developed by the Eureka 147 Consortium. Only the USA has currently opted for a different system (Japan is undecided) and American technicians openly confess Eureka is superior - but their choice is largely based more on cultural logistics. Eureka offers interference-free reception for stationary, portable and mobile sets; superior coverage; easily selectable services, wider choice of programmes, possibilities for encrypted services; associated text, pictures and multimedia applications.

The DAB transmission system is also more economically efficient and friendly as lower power levels are required than traditional broadcasting. The system is fully specified, tested and evaluated by independent authorities and regulatory bodies. Nonetheless, the transfer of this exciting and exceptional new technology has taken nearly ten years to reach the marketplace. As the world evolves, creating a single standard for anything becomes increasingly difficult - look at the different formats for video discs and the emerging plethora of concepts for higher capacity data discs to replace CDs. It is a tribute to the World DAB forum that all but the USA look set to follow one path. Speculation also surmises that America may well eventually be forced to 'jump horse'. Even Japan, often so closely associated with American consumer demands, is seriously considering Eureka for its domestic market.

The good news is that the consumer will actually benefit from the 'time lag' political debate has created. As a result, DAB technological development has become extremely advanced and sophisticated and consumers can be assured that even early domestic sets will be extremely advanced and robust in design. Initial receivers are likely to be aimed at the in-car market, but hi-fi, portable and Walkman (or will they be called DABman) sets will swiftly follow. PC Card DAB receivers are also reaching the advanced development stage - ready to embrace high speed data delivery alongside the latest songs from The Verve and live broadcasts of concerts by the London Symphony Orchestra.

Technical development of DAB has been undertaken since 1987, largely in the context of the Eureka initiative of the EU. The Eureka-147 system applies to both terrestial and satellite systems and has been accepted as a world-wide standard by the International Telecommunications Union (ITU).

The DAB standard is capable of operating at any frequency from 30 MHz to 3 Ghz and above, the real consideration being the allocation of spectrum for such use rather than technical issues. Internationally, frequencies have been agreed in the L-Band (1.4 GHz) and S-Band (2.3 GHz) and more recently VHF Band III (217 to 230 MHz) which the UK will initially use. L-Band allows for 9 multiplex frequency blocks but its allocation will not be available in the UK until 2007. Until that time just 7 frequency blocks can be utilised within VHF Band III.

DAB receivers were officially unveiled in Berlin at the International Consumer Electronics Fair in September 1997. A second phase of cheaper and more sophisticated DAB sets are expected to be launched by a large number of major manufacturers during the summer of 1998. It is likely DAB car receivers will be the most prevalent initially. Hi-fi sets and PC card tuners are likely to follow swiftly afterwards with portable DAB radios hitting the market early in 1999.

In 1994, the DTI announced the first allocation of spectrum for DAB in the UK : 217 - 230 MHz in VHF Band III. The available spectrum is divided into 7 multiplex blocks, each provides capacity for a minimum of 6 stereo programme channels plus some data services. Of these, one block is reserved for BBC National Radio and another for National Commercial Radio services. This means that there will be capacity for at least three other national commercial services. The remaining 5 blocks will carry BBC and commercial local/regional services. Metropolitan areas will have 2 multiplex frequency blocks (12 or more programme services), so that most areas will have capacity for new services along with simulcasts. There are likely to be 3 multiplexes in London, where there are already 17 analogue services.

Source : BBC DAB Web Site

The BBC led the field in building out its DAB transmission network. Its DAB services began in London in September 1995, operating from 5 transmitters in a single frequency network. The next phase increased the number of DAB transmitters to 27 which provides coverage for 60% of the UK population. This phase extended BBC DAB transmissions to major metropolitan areas like Belfast, Bristol, Birmingham, Edinburgh, Glasgow, London, Liverpool, Manchester, Newcastle and the main motorway routes of England.

After 2 short term tests in London and Birmingham, long-term commercial radio pilots were operated in London by National Transcommunications Ltd (NTL) and British Telecom (BT). Both commercial trials involved simulcasting as well as experiments with new services.