Photo by Abderrahmane Meftah / Unsplash
First data transmissions
Forty years ago, at a local radio station in Bristol, host Joe Tozer and Chief Engineer Tim Lyons launched Datarama with management approval . It was dedicated to personal computers, and its feature was the transmission of programs "over the air."
Authors played cassettes on the air, and listeners recorded sounding noises with their tape recorders. Then they were connected to a computer, and the computer interpreted the cacophony of sounds as a sequence of bytes. This is how the audiotape with the Sinclair Spectrum software sounded .
As a test of the pen, the authors decided to send the audience a coded photograph of Cheryl Ladd , the star of the TV series Charlie's Angels. True, the image had a resolution of only 40x80 pixels, so it was quite difficult to recognize the American actress.
The audience appreciated this way of conveying information, and soon Joe began to share entire programs, including those written for the show. They were originally intended for the BBC and Sinclair ZX81 computers , but later expanded the list to Commodore and Dragon 32/64 .
From pictures and software to games
Around the same time, the Dutch Broadcasting Association aired a radio show similar to Datarama called Hobbyscoop. The presenters conveyed to the audience not only programs, but also computer games. The company developed the BASICODE cassette format for BASIC applications to be compatible with a wide range of computers.
BASICODE was a 1200BPS RS232 signal with FSK modulation . The zero bit was encoded with one period of the 1200 Hz baseband signal, and the one bit was encoded with two periods of the 2400 Hz signal. A similar type of modulation was used by the BBC's Acorn computers.
Mass phenomenon
Radio programs with "software distribution" existed in many European countries. From 1983 to 1986, the hosts of the Yugoslav show Ventilator 202 broadcast 150 programs in this way: from calculators to flight simulators. The project was initiated by the editor of the computer magazine Galaksija. By the way, it was one of the key resources promoting the culture of open source software and hardware throughout the country.
Photo Belinda Fewings / Unsplash
In one of the issues, the authors even published an assembly diagram for a DIY computer, which quickly became "popular". Instead of an expensive (at that time) graphics chip, the computer used a cheap Zilog Z80A microprocessor to generate graphics.
Fan 202's programs were so popular that portions of them were broadcast on national television. But with the advent of accessible storage media - in particular, floppy disks - the culture of broadcasting programs by radio quickly faded away.
Additional reading in the "World of Hi-Fi":
Where to listen to the squeak of the ZX Spectrum, PC Iskra-1030 and the sounds of old household appliances
How to turn a computer into a radio, and other ways to extract music from computing systems
How to reproduce realistic sound in computer games and VR and why it's hard
What radio listeners and radio presenters hate
Russian radio plays: from Radionyani to Solaris Radio plays
: a very well forgotten old