Ismaning radio transmitter
The Transmitter Ismaning was a large radio transmitting station near Ismaning, Bavaria, Germany. It was inaugurated in 1932.[1] From 1932 to 1934 this transmitter (which replaced the Stadelheim Transmitter at Munich-Stadelheim) used a T-antenna as transmitting antenna, which was spun between two 115-metre-high free-standing wooden lattice towers, which were 240 metres apart. As this antenna had an unfavourable vertical radiation pattern, which produced much skywave resulting in a too small fading-free reception area at night, in 1934 a new antenna was installed. Therefore, one of the towers was dismantled and rebuilt on a 39-metre-high (128 ft) wooden lattice base. While this work took place, an L-Antenna was used, which was spun between the other tower and a small auxiliary wooden tower. It became defunct in 1977 and was destroyed in 1983.
Wooden broadcasting tower
After completion of the new wood tower, which was 156 metres high without the arms carrying the antenna (with these arms its height amounted to 163 metres),
Services transmitted
Bavarian Broadcasting Company
The transmission facility Ismaning is used for transmitting the first program of the Bavarian Broadcasting Company on the medium wave frequency 801 kHz (transmission power 600 kilowatts until 1994, now 100 kilowatts) and for all programmes of the Bavarian Broadcasting company in the FM range. Until 1994 there was also a transmitter of the American Forces Network (AFN), with its AFN Munich station, at Ismaning.[3][4]
For the AM transmissions a 171.5-metre-high[5] guyed steel tube mast[6] is used. This mast is insulated from the ground and is designed as a fading reducing transmission aerial with multiple feeding. Therefore, it is separated at 56 metre and 117 metre heights by insulators.
Restrictions of the
As back-up aerial a 105-metre-high, guyed steel framework mast was built in 1947[3][4] close to the transmitter building. This mast, which was originally used for transmitting the program of AFN was until 1969 126 metre high and carried from 1958 to 1969 aerials for FM transmissions.
Restriction by the waveplan of Copenhagen had the result, that the mediumwave transmitter of the Bavarian Broadcasting Company had to work with directional radiation with minimum toward Northeast after 1951 at nighttime. This type of radiation was not possible with the aerial on the wood framework tower and a directional aerial consisting of two insulated guyed radio masts with a height of 94 metres had to be built.[9][10][11]
This aerial was until 1969 for transmitting the program of the Bavarian broadcasting company during nighttime in service. After 1969 it was used until its shutdown in 1994 for transmitting the program of AFN on 1107 kHz. In difference to the time before 1969 omnidirectional radiation was used. One mast was used and the other one was a spare unit.
As aerials for shortwave transmissions of the Bavarian broadcasting company there are a dipole aerial, built in 1976, which hangs on two guyed steelframework masts with a height of 35 metres and a winkle dipole which hangs on three guyed steel framework masts with a height of 55 metres. The winkle dipole aerial went in service in 1980.
For FM broadcasting transmission, there is a silvery grey guyed steel framework mast with dipol arrays on its top near the station building. This mast, which was built in 1977, has a height of 100 metres and is the only mast at the transmitter Ismaning, which is grounded.[12][13]
Voice of America
The
In 2010, a 210-metre-tall (690 ft) new guyed mast for FM broadcasting was built.[19][20]
See also
- List of towers
- List of masts
- List of famous transmission sites
References
- ^ "Sendeturm Ismaning (Ismaning, 1934)".
- ^ "Drawings of Sendeturm Ismaning - SkyscraperPage.com".
- ^ a b "Drawings of AFN-Sendemast Ismaning - SkyscraperPage.com".
- ^ a b "AFN-Sendemast Ismaning (Ismaning, 1947)".
- ^ "Drawings of MW-Sendemast Ismaning - SkyscraperPage.com".
- ^ "MW-Sendemast Ismaning (Ismaning, 1969)".
- ^ "Reflektormast Ismaning (Ismaning, 1978)".
- ^ "Drawings of Reflektormast Ismaning - SkyscraperPage.com".
- ^ "Drawings of Richtantenne Ismaning, Mast Nordost - SkyscraperPage.com".
- ^ "Drawings of Richtantenne Ismaning, Mast Sudwest - SkyscraperPage.com".
- ^ "Richtantenne Ismaning (Ismaning, 1951)".
- ^ "Drawings of UKW-Sendemast Ismaning - SkyscraperPage.com".
- ^ "UKW-Sendemast Ismaning (Ismaning, 1977)".
- ^ "Drawings of Sendemasten der Voice of America 1 - SkyscraperPage.com".
- ^ "Drawings of Sendemasten der Voice of America 2 - SkyscraperPage.com".
- ^ "Drawings of Sendemasten der Voice of America 3 - SkyscraperPage.com".
- ^ "Drawings of Sendemasten der Voice of America 4 - SkyscraperPage.com".
- ^ "Sendemasten der Voice of America (Ismaning, 1949)".
- ^ "Drawings of Neuer UKW-Sendemast Ismaning - SkyscraperPage.com".
- ^ "Ismaning VHF Transmission Mast (Ismaning, 2010)".