Wire radio

from Wikipedia, the free encyclopedia

Wire radio refers to the spread of radio broadcasting over the telephone network , both in baseband and RF-modulated. Both amplitude and frequency modulation are used.

technology

Wire radio broadband amplifier with tubes in a central office
Nameplate of the above wired broadband amplifier with tubes

Most of amplitude-modulated or after the carrier frequency method processed (because of disturbing interference , for example, in the late 1930s / in the early 1940s. Berlin applied) Cable radio programs in long wave - and occasionally in the medium-wave band are in a central headend via special transformers ( transformers ) in the Telephone lines fed in.

At the receiving end, the signals are decoupled from the network again. When using the transmission method over the telephone network, an antenna splitter is connected between the telephone line and the antenna input of the receiver .

The systems operating in the long wave range for transmission over the telephone network were disturbed by the harmonics of the ISDN , which are in the same frequency range. This is why wire radio had to give way to ISDN in many networks.

history

Instructions for the makeshift reception of wire radio from 1942

In Germany , amplitude-modulated wire radio used to be widespread in some cities. There were switches like the DWt 52 and the changeover switch DDa 38 to receive the wire radio with the people's receiver like the VE 301 G.

During the Second World War , wire radio transmitters were operated in Berlin, but also in other parts of Germany (e.g. Gau Hessen-Nassau , Ruhr area, Emden area) to inform the population about the air situation during attacks by enemy aircraft. The regular (terrestrial) radio transmitters were switched off during this time so that they could not be used by the enemy bombers for navigation using radio direction finding . The Reichssender Wien showed z. B. with a "cuckoo call" to the imminent shutdown. After that, reception was only possible via wire radio. Here, the ticking of the clock served as an indication of the interruption of the normal program, and the listeners could also tell from the ticking that the wire radio was in operation and their system was working even if no announcements were being made over the wire radio. Instructions to the population came after the announcement “This is the wire radio speaking. We give an air situation report ... ".

During the war years, apart from the German broadcaster, only the unified Reichsrundfunkprogramm was initially fed in via wire radio. After 1942, the Reichspost put all three channels into the service of air warning. From this point on, the signal was not only fed into the telephone lines officially connected to the wire radio, but was also sent across the entire network to disseminate the air situation reports. So anyone could connect the receiver to the phone using a simple wire, as the instructions for makeshift reception shown opposite explain.

After the Second World War, the US Headquarters Berlin ordered the resumption of wire radio in December 1945 in the absence of its own medium and long-wave transmitters in the American sector, and the later RIAS began its activity in Berlin under the name DIAS (= wire radio in the American sector).

The wire radio was available in northern Germany in the cities of Hamburg, Kiel and Lübeck. The program of the Nordwestdeutscher Rundfunk ran on 250 kHz, while the BFN (British Forces Network, British soldier broadcaster) program was broadcast on 160 kHz.

Wire broadcasting ceased in West Germany on June 30, 1963 and in West Berlin in 1966.

The Switzerland operational until early January 1998, a cable radio network with six programs ( Swiss telephone broadcast ). However, this long-wave system did not get along with the harmonics of the ISDN, which interfered with the signals of the telephone broadcast. The telephone slogan therefore had to be discontinued with the introduction of ISDN.

In Austria , three programs could be received by wire radio (long wave) over the telephone network, which was used before coverage with VHF transmitters in areas with poor reception quality in the medium wave range.

In Italy , wire radio called filodiffusione was introduced in 1958 to enable coverage of the entire country. Even today, the larger cities, such as the main towns in the provinces, are still supplied, and there are still around 300,000 recipients (as of 2005).

In Hungary , the engineer Tivadar Puskás established what was ultimately a commercially successful (similar to today's pay radio ) wire radio system in Budapest at the end of the 19th century . The telephone Hírmondó (literally: telephone (pre-) messenger ) started in 1893 26 years before the first regular wireless broadcast of programs by Hanso Schotanus à Steringa Idzerda and was discontinued between 1924 and 1930. The maximum line length in Budapest was around 1200 km with 9107 participants. Tivadar Puskás was honored for his services with a bust in the entrance hall of the International Telecommunication Union in Geneva .

Wire radio was widespread in the Soviet Union , since wire radios could only receive Russian stations fed into the network; this should limit unwanted listening to foreign stations. Some wire radio networks in the former USSR are still in operation today. In Moscow and Zelenograd is currently a project in the pipeline, which is to convert the existing analog cable radio network in an affordable narrowband cable connection.

Wire radio is still used in some other countries. In addition to public service, wire radio also served as a means of communication in hospitals and nursing homes. However, with the advent of VHF broadcasting, it quickly lost its importance and was gradually discontinued. Cable television and web radio are the modern successors to wire broadcasting .

See also

Individual evidence

  1. ↑ http://www.rkk-museum.ru/vitr_all/713_e.shtml
  2. ↑ http://www.maz-online.de/Lokales/Potsdam/Blindgaenger-in-Potsdam/Die-Nacht-von-Potsdam/Potsdam-Timeline-der-Bombardierung-am-14.04.1945 The night of Potsdam. Allied air raid on April 14, 1945 destroys the city center. The minutes of the bombing night in Potsdam. maz-online.de, April 14, 2015, updated April 15, 2015; accessed November 12, 2015. - Renate Jungmann hears sirens and over the radio: "Major attack on Potsdam (imminent)"
  3. ↑ "This is where the wire radio speaks ..." In: Kleine Volks-Zeitung . July 25, 1944, p. 4 ( ANNO - AustriaN Newspapers Online [accessed May 27, 2020]).

Web links