Abstimmhaus Reservesendeturm Beromuenster1

An antenna tuning hut or helix house is a small shed at the base of a

longwave In radio, longwave (also spelled long wave or long-wave and commonly abbreviated LW) is the part of the radio spectrum with wavelengths longer than what was originally called the medium-wave (MW) broadcasting band. The term is historic, dati ...

mediumwave Medium wave (MW) is a part of the medium frequency (MF) radio band used mainly for AM broadcasting, AM radio broadcasting. The spectrum provides about 120 channels with more limited sound quality than FM stations on the FM broadcast band. Duri ...

radio transmitting antenna. It contains

antenna tuner An antenna tuner, a matchbox, transmatch, antenna tuning unit (ATU), antenna coupler, or feedline coupler is a device connected between a radio transmitter or receiver and its antenna to improve power transfer between them by matching the imped ...

— radio equipment for coupling the power from the

feedline A radio transmitter or receiver is connected to an antenna which emits or receives the radio waves. The antenna feed system or antenna feed is the cable or conductor, and other associated equipment, which connects the transmitter or receiver w ...

to the antenna. Alternative names include ''antenna tuning house'', ''coupling hut'', and ''dog house''.

Equipment

The radio frequency current from the transmitter is supplied to the antenna through a cable called the

. The antenna tuning hut contains a

matching network In electrical engineering, impedance matching is the practice of designing or adjusting the input impedance or output impedance of an electrical device for a desired value. Often, the desired value is selected to maximize power transfer or ...

made of high wattage

capacitor In electrical engineering, a capacitor is a device that stores electrical energy by accumulating electric charges on two closely spaced surfaces that are insulated from each other. The capacitor was originally known as the condenser, a term st ...

s and

inductor An inductor, also called a coil, choke, or reactor, is a Passivity (engineering), passive two-terminal electronic component, electrical component that stores energy in a magnetic field when an electric current flows through it. An inductor typic ...

s (coils) that in combination match the antenna's impedance to the feedline, to efficiently transfer power into the antenna. The

s, made of large

helix A helix (; ) is a shape like a cylindrical coil spring or the thread of a machine screw. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is for ...

es of wire, give the name ''helix house''. The powerful

radio wave Radio waves (formerly called Hertzian waves) are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths g ...

s near the antenna can be a hazard for workers, so the interior of the antenna tuning hut is typically shielded with copper or aluminum sheeting or wire mesh, in order to reduce radiation from the tower. In operation the components can have a voltage of several hundred thousand volts. The building may also contain lightning protection devices and power transformers for

aircraft warning light Aviation obstruction lighting is used to enhance the visibility of structures or fixed obstacles which may conflict with the safe navigation of aircraft. Obstruction lighting is commonly installed on towers, buildings, and even fences located in ...

s on the tower. The

radio transmitter In electronics and telecommunications, a radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna with the purpose of signal transmissio ...

which generates the radio frequency current which powers the antenna is generally located away from the antenna, to prevent the powerful radio waves from interfering with the sensitive transmitter circuits.

References

Radio technology {{radio-comm-stub

Equipment

See also

References