|man_made = communications_tower|
|A huge tower for transmitting radio applications|
|Used on these elements|
|Tools for this tag|
A man_made=communications_tower is a huge tower for transmitting radio applications like television, radio, mobile phone or officials radio. It is often made from concrete and usually a far visible landmark. An indication could be a height greater than 100 meters.
- 1 Functions
- 2 Note
- 3 Distinguish between other kinds of communications towers
- 4 Examples
- 5 Possible tagging error
Radio towers can either carry antennas or act directly as antenna. In latter case one speaks from mast or tower radiators. Most transmission antennas for VLF, LF and MF are mast or tower radiators. Usually mast and tower radiators are insulated against ground, but there exist also grounded structures, at which the power to be radiated has to be fed in the tower at a certain height.
For towers used as radiator, one should use
for towers and masts insulated against ground, one should use
There are two basic types of radio towers carrying antennas: such carrying antennas for transmitters whose wavelength is small to the size of the tower and those whose wavelength is in the size of the tower or greater. In the first category belong all towers carrying antennas for transmitters in the VHF/UHR/SHF-range, these are for example FM-radio-, TV-, cellphone or radio relay transmitters, in the second category belong towers carrying L-, T- or triangular antennas for VLF, LF and MF-transmissions and towers carrying shortwave transmission antennas. Towers of the first category are always grounded, while towers of the second category may be insulated against ground in order to get a better effiency.
A radio tower can serve simultanously as antenna and as antenna carrier. This is realized at towers used simltanously for FM- and AM-broadcasting. Also a tower can carry as well antennas for transmitters with wavelengthes greater than the tower height and for transmitters with wavelengthes much smaller than the tower height, which is also realized at towers transmitting AM- and FM-radio simultanously.
Please, keep in mind, that neither this page nor any other source gives a clear verifiable way to distinguish between the objects, supposed to be tagged with man_made=communications_tower and man_made=tower tower:type=communication respectively. "Huge" or "really big" are relative non-verifiable characteristics - using it contradicts the fundamental OSM principle. Many regional broadcasting towers (supposedly meant to be tagged as man_made=communications_tower ) in hot climate or less wealthy countries have the access ladders outside and have no elevator, while many "conventional" towers with tubular design have a ladder inside it. Height greater than 100 meters can be seen even in some longwave transmission masts. So, these two features are non-distinctive.
Distinguish between other kinds of communications towers
First question: Is it a mast or a tower?
Second question: What kind of services are being provided?
No mast any more, but a tower
Really big communications towers >= 100 m: