Editorial

"All changed, changed utterly: a terrible beauty is born"
George T. Waters

A Century of Wireless

The studio
J.J. Bottom and B. Marks (628 KB)

In the embryonic days of sound broadcasting, the microphone and the transmitter were located in the same room. It was not long however before the radio studio developed as a separate entity to the transmitter.

Over the decades, tremendous developments took place in the studio but, as the first century of wireless draws to a close, the trend now – at least with local-area radio stations – is to combine the studio once more with the transmitter site, in a space no larger than most living rooms.

In this brief review, the authors have attempted to cover just some of the key technical developments which have taken place in the radio studio over the years. The topics considered include the microphone, sound mixers, recording and playback devices, stereo programming and studio acoustics.

The transmitter
R.E. Fenn (730 KB)

This article outlines the major developments which have taken place in sound transmitter equipment and techniques – from the first experiments before the invention of the thermionic valve, up to the present time.

Over the years, high-power transmitters have developed into very sophisticated systems. Their progress was initially driven by a thirst for ever-increasing power and audibility. Today, like with many other things, their development is driven by the quest to reduce capital and operating costs.

The receiver
J. Hill (565 KB)

This article reviews the major trends and developments which have taken place in the design of wireless receivers, from the crystal set of the 1920s to the arrival in the 1960s of cheap transistorised radios, manufactured in the Far East.

In the early days of sound broadcasting, a domestic wireless manufacturing industry evolved in many of the developed countries of the world. Thus, although this article relates mainly to British-made wireless sets, it is acknowledged that similar receivers were made in other countries.

International frequency regulation and planning
F.M. Woolley (2.7 MB)

At the origin of the regulation of radiocommunications was the problem of harmful interference, and the need to improve the safety of life at sea. As demand for spectrum grew, the need to use it more efficiently was a further incitation to regulation, which came to include frequency planning.

This article describes the development of the regulation and planning of the use of the radio frequency spectrum, with emphasis on those aspects of special relevance to broadcasting.

The adaptation of ITU structures to the changing requirements of this task is described, including the changes adopted in 1992, and the current moves to simplify the Radio Regulations.

From the coherer to DSP
M. Lemme and R. Menicucci (xxx KB)

This article reviews the development of electronic devices used over the last century in wireless communication. It looks at early receiving devices such as the coherer, the magnetic detector and the cat's whisker, progressing to the thermionic valve, the semiconductor, the microchip and digital signal processing.

On the transmission side, the early devices discussed include the spark-gap generator, the voltaic-arc generator and static frequency multipliers. This is followed by a brief description of more modern power devices, including thermionic valves and electron-velocity control tubes.

A century of trust in Mother Nature
R. Levey (156 KB)

The 100th anniversary of Marconi's first long-distance wireless transmissions is inevitably a pretext for many to claim their share of the credit for inventing sound broadcasting.

While interest is centred on the pioneers and their creative experimentation, it is important to reflect also on the uses that have been made of this revolutionary technology, and perhaps to ponder on the last great mystery of wireless transmission.

Six great pioneers of wireless
M. Meyer (403 KB)

As stressed elsewhere in this issue, no one person was responsible for "inventing" wireless. It is broadly agreed that the works of Faraday, Maxwell and Hertz where vital in laying the foundations for Guglielmo Marconi, who was the first to exploit the practical applications of electromagnetic waves.

To complement the portraits given here of these four great pioneers, the experimental works of Lodge and Popov are also reviewed. Some authorities feel that Lodge's important contribution to the history of wireless has been sadly neglected over the years while, in Russia, Popov is regarded as the inventor of radio communication.

To complete this review, a brief chronology of important events in the history of wireless is given, from the discovery of static electrical charges around 600 B.C. to the European and International adoption of a single standard for tomorrow's wireless system – Digital Audio Broadcasting (DAB).