Skew is a term used in
antenna engineering. It is a technique to improve the horizontal
radiation pattern
In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the ''directional'' (angular) dependence of the strength of the radio waves from the antenna or other source.Constantine A. Balanis: " ...
of a high power
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.
Choice of location
The location may ...
.
In a high power
VHF or
UHF
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...
station, usually the antenna system is constructed to broadcast to four directions each separated 90° from each other. So the directivity of the antenna system resembles a
four leaf clover. While settlements within the
main lobe
In a antenna (electronics), radio antennas, the main lobe or main beam is the region of the radiation pattern containing the highest Power (physics), power or exhibiting the greatest field strength.
The radiation pattern of most antennas shows ...
receive enough energy, the energy received by the settlements between the main lobes may be 6 dB less.
One popular method to solve the problem is to skew the antenna panels symmetrically around the central axis of the mast.
[R.Busi: ''High altitude VHF and UHF Broadcasting stations'', EBU technical center, Brussels, 1967 p 25] Usually a skew of λ/4 gives the desired almost-uniform horizontal radiation pattern. But in cases where more than one
RF signal is applied to antenna system (via
combiner
Power dividers (also power splitters and, when used in reverse, power combiners) and directional couplers are Passivity (engineering), passive devices used mostly in the field of radio technology. They couple a defined amount of the electromagne ...
), the improvement in the horizontal radiation pattern may be inadequate for some signals.
References
{{Analogue TV transmitter topics
Antennas (radio)
Broadcast engineering