The process of radio programme transmission involves the modulation of the carrier with the programme output of the radio station. The carrier can be either a radio wave or carried on copper cables or other material - fibre is become more widespread and will become THE standard method of distribution within our lifetime. Where fibre isn't feasible, radio waves will continue to be used.
BROADCAST STUDIOS
Less than a generation ago, radio and TV studios would use very expensive equipment; a typical radio studio would cost between £20,000 and £150,000 to build. This can now be achieved for a couple of thousand pounds and the resulting studio will provide much better audio quality than previously. It will also be much easier to operate!
This section is concerned with the programme origination, at the studio part of the transmission chain. From there it is processed to match the method of distribution (FM and AM processing are each done differently.
Microphones have improved and their size and cost has plummeted. For many years, large broadcasters have insisted on using high end microphones, but these are not really required for most radio broadcasting.
A decent quality microphone will still cost between £75 and £400, but pay much more any you may be hard pushed to tell the difference in sound.
Digitisation has revolutionised radio studios and programme origination. Until very recently all sound sources in radio studios were analogue, which means they sent a contant stream of varying audio information to the user. Sound sources were traditionally quite large and they used separate cables for each source, until the point of mixing. Digital has decimated the size and cost of almost every item (except human beings; we are probably next!).
Digital audio has had some really profound effects in four distinct areas of the operation of radio stations. These are seen most in controllability, miniaturisation and especially in cost.
AUDIO PRODUCTION
Many sources have changed beyond all recognition, especially in size. The adaption of digital techniques, in particular the use of compression, renders files much smaller and make it possible to record on very small (physically) media.
Controlability of equipment has become easier, with remote operation of sources being simple to achieve.
ADMINISTRATION
These parts of a radio station are vital in tracking royalty liabilities and commercial loading, plus other revenue streams. Now all logging of music played can be done automatically, (it was previuously a manual chore).
PLAYOUT
This has become far more efficient, smaller and thus very much cheaper. The kit is also much more easily controlled, smaller, faster and cheaper too. Control is a key aspect of digital's improvements: instead of having to be adept at equipment operation or the technical parameters radio presenters are free to concentrate on programme content.
The key source of equipment for most radio stations is the item with which it all began - the microphone. In the early days of radio this was a huge contraption mounted on a trolley. To add music, the microphone would be wheeled over to an ensemble of live musicians, or placed next to a gramophone - electric pickups for turntables only came in ten years after broadcasting started.
Previously all interconnection of audio, and often of switching circuitry too, had to be in screened audio quality cable. Dozens of cables can now be replaced by a simple network of Ethernet cables, sometimes (wrongly) referred to as “Cat 5”.
An Ethernet cable is simply four pairs of twisted cable in one encapsulation, with a small modular 'RJ' connector at each end. It can carry multiple signals, but take care to select the correct one as there are some variations and its important to have the right cable correctly terminated in the right connector.