Telephone slogan

The telephone broadcast was from the end of 1931 in Switzerland in use wire broadcasting method for transmitting radio programs via telephone lines , initially in low frequency technology, from 1940 through trägerfrequenter vibrations in the long-wave range.

The telephonic message was particularly important in the mountain regions, which were poorly served by the regional broadcasters Beromünster , Sottens , Monte Ceneri and Savièse , until the advent of VHF broadcasting. The three domestic channels of the SRG as well as three other channels were broadcast.

At the end of 1997, the telephone broadcast was discontinued with the introduction of ISDN , as the harmonics of the ISDN interfered with the telephone broadcast signals. In Italy , the Filodiffusione system , similar to the telephone slogan , which was introduced in 1958, is still in operation.

history

Junction box type G model 66 for the telephone announcement

1931

The radio programs were initially only broadcast terrestrially via medium wave . However, especially in the mountain valleys, the reception was disturbed due to the few transmitters. Therefore, from 1931, the PTT introduced the telephone broadcast. The PTT operated the transmission systems (medium wave, short wave, VHF) for the broadcasting companies until 2002, so the connection between telephone and radio was obvious. After the PTT was split up into Post and Swisscom , Swisscom Broadcast AG took over the operation of the transmission systems.

1940

With the introduction of the HF-TR high-frequency telephone broadcast, it became possible to transmit several programs over the telephone line independently of an ongoing telephone call. Previously, the radio reception was interrupted when you picked up the receiver to make a phone call.

1956

Telephone broadcast receiver Sondyna Hawaii 7003 with six preset buttons (1970)

The following six programs were broadcast:

• The first program from Schweizer Radio DRS
• The first program from Radio de la Suisse romande
• The first program from Radio della Svizzera italiana
• "Classic"
• «Light»
• "International", compiled from contributions in English specially produced for the TR and contributions from Schweizer Radio International (SRI)

1969

There are more than 400,000 phone broadcast recipients in Switzerland.

1998

An annual deficit of CHF 10 million and the lack of a legal basis for cross-subsidization mean that the telephone broadcast is discontinued. But also other services such as ISDN and ADSL technically prevent the continuation of telephone broadcasts. In future, reception via satellite will be possible in areas with no terrestrial coverage or abroad.

The technology

The NF-TR low-frequency telephone slogan, introduced in 1931, simply worked: Instead of a telephone call, the radio program was transmitted over the telephone line. However, the low possible transmission power of a few milliwatts required an amplifier at the receiver. In addition, the telephone announcement was interrupted during a telephone conversation.

That is why the HF-TR high-frequency telephone slogan was introduced around 1940. With this multiplex process it was possible to transmit six programs at the same time without these having to be interrupted during a telephone call. The technology has a systemic similarity to the DSL introduced later ; However, due to expanded frequency bands, digital transmission and a different modulation method, this cannot be directly compared with the telephone broadcast.

The programs were transmitted amplitude-modulated on the following frequencies:

• Channel 1: 175 kHz
• Channel 2: 208 kHz
• Channel 3: 241 kHz
• Channel 4: 274 kHz
• Channel 5: 307 kHz
• Channel 6: 340 kHz

The receiver was connected to a special junction box. A well-known manufacturer of telephone broadcast receivers was Biennophone. Since these devices were specially manufactured for Switzerland, they often also had Swiss names, for example the Weggis 5860 model from 1958. However, reception was also possible with any radio set that was designed for the long wave range. Since the channel grid was defined as 33 kHz, instead of 9 kHz, as is usually the case with long-wave broadcasting , the audio signal could be used with the special HF-TR devices with a higher bandwidth. In the case of standard long-wave receivers, which were also designed to receive terrestrial transmitters, only a bandwidth of less than 9 kHz was transmitted. Due to this fact, the pure HF-TR devices were popular with audio enthusiasts at the time.

Web links

• Information about telephone broadcast

Individual evidence

1. ↑ Hawaii 7303. In: radiomuseum.org. Retrieved May 27, 2020 .