Long wave transmitter
A long-wave transmitter is a transmission system for electromagnetic waves with frequencies in the long-wave range , i.e. in the frequency range between 30 kHz and 300 kHz.
Long-wave transmitters are used to transmit time signals , broadcast radio coverage, the sending of weather reports from the DWD as radio telex or in fax format , the transmission of telegraphic messages or radio navigation . A narrow frequency band at 137 kHz is also available to amateur radio . The radio transmitters for long wave are operated in the frequency range between 148.5 kHz and 283.5 kHz with outputs from 10 to 2500 kilowatts. The first commercial transmitters were often pop-spark transmitters until the introduction of electron tubes in transmitter construction , later also extinguishing spark transmitters or machine transmitters .
The definition of the transmission frequencies used, the transmission power and whether and in what form directional radiation may be used was laid down in the 1974/75 Geneva Wave Plan , which came into force on November 23, 1978. Some intergovernmental coordination of this plan has now been carried out. In Germany, the Federal Network Agency issues the current frequency plan.
For long wavelengths of one to ten kilometers, correspondingly large and sometimes very high transmission antennas are required. Some transmission antennas of long-wave transmitters (e.g. the Konstantynów transmission mast with 646 m) were among the tallest structures on earth.
As transmission antennas for omnidirectional radiation , self-radiating transmission masts isolated from earth with base feed or earthed self-radiating transmission masts with top feed , sometimes also trap or T antennas, are used.
Arrangements of several self-radiating transmission masts are used for directional radiation . In addition, vertical traps mounted on earthed towers or masts , T-antennas , Alexanderson antennas or shield antennas , which are usually stretched between two towers or masts, which are usually isolated from earth, are also used.
For radio beacons ( NDB ), free-standing tubular masts that are only about ten meters high and isolated from the ground are usually used. Occasionally, arrangements with several masts are used, either to achieve a directional effect or to enlarge the area of near fading-free reception ( fading-reducing transmitting antenna ).
Occasionally, reference is made to "novel" antennas, as in the case of cross-field antennas . In principle, these are Tesla coils . As a transmitting antenna, however, due to extremely high losses, no significant radio coverage is to be expected from these.
From this point at the latest, a very precise distinction must be made between a transmitting and receiving antenna. Another, suggestive reason can be found under antenna technology . An exception would present their use in RFID solutions, which in the near field of work of the antenna with a range of a few tens of centimeters.
Long-wave transmitters for the transmission of telegraphic messages mostly use T-antennas or self-radiating transmission masts with roof capacity (shield antennas) suspended from masts or towers that are isolated from earth . A power of up to 100 kilowatts is used.
Use long-wave transmitters for radio navigation services if they are operated with high power like the Decca and LORAN-C , self-radiating transmission masts with roof capacity as a transmitting antenna. Long-wave transmitters for radio navigation services with low power such as NDBs mostly use small tubular masts insulated from the ground, which are hardly noticeable due to their height of only ten meters.
Well-known transmission systems
Active LW transmitters
- Long wave transmitter Kenadsa (Algeria - 153 kHz)
- Roumoules transmitter (France - 216 kHz RMC info )
- Long wave transmitter Tipaza (Algeria - 252 kHz)
- Kalundborg radio station (Denmark - 243 kHz - DRM since October 2008 , now AM again )
- Droitwich long wave transmitter (UK - 198 kHz - BBC Radio 4 )
- Clarkestown transmitter (Ireland - 252 kHz)
- Long wave transmitter Helissandur (Iceland - 189 kHz)
- Transmitter Beidweiler (Luxembourg - 234 kHz - RTL (France) )
- Long wave transmitter Ingøy (Norway - 153 kHz)
- Broadcasting station Solec Kujawski (Poland - 225 kHz)
- Long wave transmitter Bod (Romania - 153 kHz Antena Satelor)
- Long wave transmitter Topolná (Czech Republic - 270 kHz Radiožurnál)
- Long wave transmitter DCF77 (Germany - Mainflingen 77.5 kHz - time signal transmitter )
- Long wave transmitter DCF39 (Germany - Burg 139 kHz - radio ripple control technology )
- Long wave transmitter DCF49 (Germany - Mainflingen 129.1 kHz - radio ripple control technology )
- Radom long wave transmitter (Poland - 55.75, 58.25, 62.45, 64.90, 76.35, 80.50, 81.35 kHz)
- Allouis transmitter (France - 162 kHz time signal, formerly AM)
Inactive LW transmission systems
- Burg transmitter (Germany - ex 261 kHz, currently DCF39)
- Long wave transmitter Lahti (Finland - ex 252 kHz)
- Raszyn transmitter (Poland - 198 and 225 kHz)
- Caltanissetta transmitter (Italy - ex 189 kHz)
- Junglinster (Luxembourg - 234 kHz)
- Long wave transmitter Motala (Sweden - ex 189 kHz)
- Wakarel transmitter (Bulgaria - ex 261 kHz)
- Transmitter Königs Wusterhausen (Germany - ex 177 kHz reserve transmitter for transmitter Zehlendorf )
- Felsberg-Berus transmitter (Germany - ex 183 kHz)
Former LW transmission systems
- Zehlendorf transmitter (Germany - 177 kHz - switched off December 31, 2014)
- Aholming transmitter (Germany - 207 kHz - switched off December 31, 2014)
- Donebach transmitter (Germany - 153 kHz - switched off December 31, 2014)
- Long wave transmitter Hamburg-Billwerder (Germany - ex 151 kHz)
- Transmitter Erching (Germany - ex 173 and later 209 and 207 kHz)
- Transmitter mast Konstantynów (Poland - ex 225 kHz)
- Long wave transmitter Orlunda (Sweden - ex 189 kHz)
Pictures of channels preserved in museums
One of the two towers of the Motala transmitter, which was shut down in 1962 (2006)
The towers of Lahti, which was switched off in 1993 (2006)
- Antenna technology
- DCF (callsign)
- Frequency band
- Shortwave transmitter
- Long wave
- Long wave broadcasting
- Medium wave transmitter
- List of known transmitters
- ↑ Радио и телевизия в Ихтиман - Предавател България. In: www.predavatel.com. Retrieved September 6, 2016 .
- ↑ a b c Deutschlandradio: press release, long wave shutdown: Deutschlandradio relies on modern distribution channels. November 28, 2014, accessed January 1, 2015 .