Editing Low frequency (section)

===Antenna heights===
Due to the long wavelengths in the band, nearly all LF antennas are [[electrically short]], shorter than one quarter of the radiated wavelength, so their low radiation resistance makes them inefficient, requiring very low resistance grounds and conductors to avoid dissipating transmitter power.
These electrically short antennas need [[loading coil]]s at the base of the antenna to bring them into resonance. Many antenna types, such as the [[umbrella antenna]] and L- and T-antenna, use capacitive top-loading (a "top hat"), in the form of a network of horizontal wires attached to the top of the vertical radiator. The [[capacitance]] improves the efficiency of the antenna by increasing the current, without increasing its height.

The height of antennas differ by usage. For some [[non-directional beacon]]s (NDBs) the height can be as low as 10&nbsp;meters, while for more powerful navigation transmitters such as [[Decca Navigator System|DECCA]], masts with a height around 100&nbsp;meters are used. [[T-antenna]]s have a height between 50–200&nbsp;meters, while mast aerials are usually taller than 150&nbsp;meters.

The height of mast antennas for [[LORAN-C]] is around 190&nbsp;meters for transmitters with radiated power below 500&nbsp;kW, and around 400&nbsp;meters for transmitters greater than {{nobr|{{gaps|1|000}} kilowatts.}} The main type of LORAN-C antenna is insulated from ground.

LF [[Longwave|(longwave) broadcasting stations]] use mast antennas with heights of more than 150&nbsp;meters or [[T-antenna|T-aerials]]. The mast antennas can be ground-fed insulated masts or upper-fed grounded masts. It is also possible to use cage antennas on grounded masts.