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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 impedance of the radio to the antenna's feedline. Antenna tuners are particularly important for use with ...
The most widely used types of feed line are coaxial cable, twin-lead, ladder line, and at microwave frequencies, waveguide. Particularly with a transmitting antenna, the feed line is a critical component that must be adjusted to work correctly with the antenna and transmitter. Each type of transmission line has a specific characteristic impedance.
The radio frequency current from the transmitter is supplied to the antenna through a cable called the feedline.The antenna tuning hut contains a matching network made of high wattage capacitors and inductors (coils) that in combination match the antenna's impedance to the feedline, to efficiently transfer power into the antenna.
FTTA architecture has enabled lower power requirements, distributed antenna sites, and a reduced base station footprint than conventional tower sites. The use of FTTA will promote the separation of power and signal components from the base station and their relocation to the top of the tower mast in a Remote Radio Head (RRH).
A diplexer allows two transmitters on different frequencies to use one antenna, and is common in installations where one repeater on 2 m and a second on 440 MHz share one feedline up the tower and one antenna. Most repeaters are remotely controlled through the use of audio tones on a control channel.
The antenna elements fed by a Butler matrix are typically horn antennae at the microwave frequencies at which Butler matrices are usually used. [4] Horns have limited bandwidth and more complex antennae may be used if more than an octave is required. [5] The elements are commonly arranged in a linear array. [6]
Remote electrical tilt is abbreviated as RET and it is part of the Antenna Interface Standards Group's open specification for the control interface of antenna devices. [ 2 ] Occasionally, mechanical and electrical tilt will be used together in order to create greater beam tilt in one direction than the other, mainly to accommodate unusual terrain .
In the 1950s and 1960s, remote control systems were introduced to allow an operator at the studio to power the transmitter on or off. [1] At the same time, an early remote control system, the Automon, was developed by RCA engineers in Montréal that included a relay system that automatically detected if the transmitter was operating outside of ...