Weiskirchen transmitter

Former medium wave transmitter 2005

Basic data

Place:

Weiskirchen ( Rodgau )

Country:

Hesse

Country:

Germany

Altitude :

120 m above sea level NHN

Coordinates: 50 ° 3 '21.6 " N , 8 ° 51' 50.4" E

Use:

Broadcasting station

Demolition :

April 11, 2012

Data on the transmission system

Number of towers / masts:

2

Height of the towers / masts :

126.5 m

Construction time:

1967

Operating time:

1967-2010

Waveband :

AM station

Radio :

MW broadcasting

Position map

Weiskirchen transmitter

The Weiskirchen broadcaster of the Hessischer Rundfunk was located in the north-western district of the Hessian town of Rodgau near the Autobahn 3 . For cost reasons, the Hessischer Rundfunk has ceased broadcasts on medium wave from January 1, 2010, thus also the operation of the Weiskirchen station.

On April 11, 2012 at 12:30 p.m. both transmission masts were laid down by detonating guy ropes.

Frequency and radiation

Guy wires of the western transmitter mast with the grounding coils

From 1967 to 2012, the Rodgau district of Weiskirchen was the location of a medium-wave transmitter for the Hessian broadcasting company for the frequency 594 kHz . Until the switch to frequencies divisible by nine as part of the Geneva Wave Plan in 1978, the transmission frequency was 593 kHz. Until 1994 the transmission power was 400 kW . From 1994 only 300 kW were used for transmission. The Weiskirchen transmitter had a directional antenna, which consisted of two 126.5 m high self-radiating transmission masts in a steel frame construction, isolated from the ground . In contrast to other medium-wave transmission masts, the guys used were not subdivided with insulators, but rather grounded via coils, which were located directly next to the anchor block. In this way, maintenance work on surge arresters was avoided on intermediate insulators that were difficult to access. The Weiskirchen transmitter worked with the transmitter on the Hoher Meißner in single- frequency operation . Here, too, medium wave operation ended on January 1, 2010. The directional diagram of the Weiskirchen transmitter had a maximum in the north-west and two minima in the north-east and south-east direction. By regulating the feed-in power for each transmission mast, the directional diagram could be changed, in cooperation with the Hoher Meißner transmitter, the maximum was even to the east.

business

The program was fed in via cable, alternatively via a radio link from the Großer Feldberg. The first transmitter, from 1967, was a tube transmitter with water-cooled tube power amplifiers . The entire transmitter was designed twice so that when a tube was changed, only a short transmission failure was generated, which was announced by the radio announcer with the words There will be a short pause in switching . The station was later modernized with a semiconductor transmitter that only had a water-cooled end tube. This modern transmitter then no longer had a reserve transmitter and worked with the energy-saving dynamic amplitude modulation (DAM) method . The energy supply was normally provided by the local power grid, in the event of a power failure by a diesel generator that starts within 10 to 20 seconds . Compressed air from bottles was used to start the generator (marine diesel). It started automatically in the event of a power failure. In emergency mode, the transmission power was reduced to around 100 kW. Since the switch to computer-aided error detection, the transmitter has also been automatically monitored from the Großer Feldberg.

building

Former residential and service building

Immediately next to the remote transmitter is the former service and residential building of the transmitter operator, the roof and outer walls of which are protected from electromagnetic radiation by an earthed copper jacket . The buildings were heated in winter by the waste heat from the tube cooling. The residential building was lived in by the station manager until the station was shut down. The actual transmitter building is also sheathed with earthed copper plates so that all measuring systems could work without interference despite the close proximity to the antenna mast.

Program supply

First, the Weiskirchen and Hoher Meißner transmitter combination supplied mobile receivers (car radios) with the VHF HR1 program without frequency switching, which was transmitted via a radio link, later via telephone cable, and converted to the medium wave frequency. Until the turn of 1989, this program was broadcast mainly to the east due to the large range in the night hours by changing the directional diagrams of both transmitters. Until the shutdown, the radio program hr-info , the program for foreigners from 7–10 p.m., as well as broadcasts of state parliament and Bundestag debates or major events were broadcast.

Dismantling

The transmitter masts were blown up on April 11, 2012

On Wednesday, April 11, 2012, at 12:30 p.m., three tension cables of the antennas were detonated. As a result, the two masts, which shaped the landscape for decades, fell in a controlled manner towards their final end.