A transmitter station or transmission facility is an installation used for transmitting
mobile telephone
or other purposes.
Choice of location
The location may be chosen to fit the coverage area
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 located at high altitudes. So, both the minimum distance regulations and the line of sight criteria are met.
Buildings and antenna masts
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
RRO
).
Most stations use mains electricity, but they also have standby generators or solar energy panels in case of failure.
[2] If the voltage of the mains fluctuates, a high power voltage regulator may be used.
Grounding
Like all industrial sites, the buildings, the antenna masts, the generators, and the transmitting equipment of the stations should be grounded for personal safety against electrical shocks. On the masts and roofs, lightning rods should be used. For transmitter stations working on frequencies below 30 MHz a good grounding is required for good function and sometimes excessive grounding systems are used. In most cases, it is desirable to connect the rods to each other to form a simple Faraday cage. But in high altitude stations, the ground is usually rocky and finding an appropriate point for the grounding bus may be impossible. In such cases, very long grounding connectors may be used to find a good ground at lower altitudes.
Operation
Transmitters may be operated by government (civil or military) or private industry. Many stations are unattended and controlled by remote control equipment.
Where operating personnel are required, personnel work on shifts and transportation may also be a parameter of station design. In such cases, accommodation, catering and health problems also play a part in station management. Especially in high altitude stations, snowmobiles must be used during winter.
(short wave). Since SW stations are assigned for very long distance communication (via reflections from atmospheric layers) they are usually employed for multi-language international services and there may be many SW transmitters in the same station.
UHF
). If two or more antenna systems have to be used, higher frequency antennas are mounted higher on the antenna mast. (The sequence of antenna systems on a typical TV-FM station may be from bottom to top; VHF-2, VHF-3 and UHF.)
Microwave stations are also high altitude stations. Although high altitude is desirable also in GSM, the operators may use low power intracity stations for areas of high population density.
References and notes
^European Broadcasting Union:Technical Monogram No.3104-1965 Site selection (Edited by RK.H.Kaltbeitzer),Chapter I, Brussels
^European Broadcasting Union:Technical Monogram No.3108-1967 High Altitude VHF and UHF Broadcast Stations (Edited by R.Busi),Chapter III, Brussels
