Linjesender

The typical powers used by linjesenders were between 250 watts and 2 kW. Most systems used frequencies in the longwave band or in between the LW and MW band although some used medium wave or frequencies below the standard LW band which required special receivers.

Wired broadcasting had several advantages over conventional broadcasting:[1]

1. Less susceptible to interference
2. Potentially greater number of programmes (as overcrowding on the frequency bands was less of a problem)
3. Potentially greater audio quality as wired transmissions were not subject to the same restrictions on bandwidth as terrestrial AM broadcasts.
4. In a mountainous country like Switzerland it was difficult to obtain satisfactory national coverage with conventional transmitters, particularly in the 1930s when transmissions were typically less powerful than today.

On the other hand there were practical and economic difficulties in extending such services to remote or thinly populated regions. Wired broadcasting could also be used by governments as a tool of censorship through promoting ownership of wire-only receivers which could not receive foreign stations.

Similar systems were used in Germany, where it was called "Drahtfunk" ("wire radio") and in Switzerland, where it was called "Telefonrundspruch" ("telephone broadcast"), both of these systems used domestic telephone lines. In some countries occupied by Germany during the Second World War these systems entirely replaced conventional broadcasting. In the Netherlands all standard receivers were confiscated and replaced with wire-only sets (Draadomroep) as these could receive local and German broadcasts but not enemy stations such as the BBC. Wire broadcast systems were also deployed in parts of the USSR.

In the 1930s some towns in Great Britain used wire broadcasting experimentally either over dedicated cables (sometimes as baseband audio) or through power lines. However as the coverage of conventional broadcast stations improved the popularity of these "radio relay" or "rediffusion" systems waned and local councils were often hostile to their installation.

• Drahtfunk A similar system in Germany.
• Telefonrundspruch A similar system in Switzerland.
• Draadomroep A similar system in the Netherlands.
• Filodiffusione A similar system in Italy.[4]
• Cable radio An FM based system still used in some parts of the world.
• Théâtrophone A system for disseminating opera and theatre performances over the public telephone network which predates regular broadcasting.
• Carrier current A system used in the United States and some other places for very localised distribution of radio programming over electric power cables.
• Satellite radio
• Power line communication
• Music Choice
• CRN Digital Talk Radio Networks
• Galaxie
• Max Trax
• DMX (music)

• http://www.wabweb.net/radio/radio/lw2.htm
• https://web.archive.org/web/20060524151218/http://nrhf.no/nrhf-sendere-AM.html