Transmitter station

A transmitter station or transmission facility is an installation used for transmitting radio frequency signals for wireless communication, broadcasting, microwave link, mobile telephone or other purposes.

The location may be chosen to fit the coverage area and for VHF-UHF-applications line of sight consideration. For lower frequencies a location with good ground conductivity is required. In case of microwave link chains, stations should be in observable ranges of each other. (see Earth bulge) Computer programmes for the terrain profile and abacs are used in addition to on site observations. Avoidance of industrial noise is also taken into consideration. Another parameter may be the government regulations concerning public health requiring a minimum distance to human habitation. The distance depends on the power and the frequency of the transmitting signal. Low power stations may be in cities; higher power stations are always in rural areas. Most of the stations (especially high frequency stations) are at high altitudes. So, both the minimum distance regulations and the line of sight criteria are met.

Stations may be housed in several buildings or a single building. In some cases the station is nothing but a small container.

They all have masts or towers to install antenna systems. In most cases the mast is a passive structure to support the antennas. But in low frequency stations (such as AM radio) the mast itself may be the active antenna element. In such cases, the mast is isolated from the ground.(See Monopole antenna). If the mast itself is an active antenna element the ground can be covered by a mesh of wires or metal elements to create a reflecting ground. Most of the stations also have facility to receive microwave signals from a microwave link or a telecommunications satellite, (TVRO or RRO).

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