Antenna Tuning

Some articles on antenna, antenna tuning, antennas:

Antenna Tuner - Sample Application: Multiband Shortwave Transmitter
... One of the longest lasting applications for dedicated antenna tuners is in high power shortwave broadcasting transmitters (50 kW+), where antenna tuning is a must due to frequent waveband changes ... Most antennas used in high power shortwave broadcasting are HRS type antennas, where the radiating elements are of a fixed length and the resonance of the antenna is optimized for only one or two bands ... It typically takes about one minute for a modern antenna tuning unit to adapt to a frequency change in a broadcast band, and about two minutes to adapt to a ...
Fractal Antenna - Antenna Tuning Units
... Antenna tuning units are typically not required on fractal antennas due to their wide bandwidth and complex resonance ... However, if a transmitting antenna has deep nulls in its response or has electromagnetic structural issues that require equalization then an antenna tuning unit should be used, per the definition of required ...