Transmitters and Antennas
LORAN-C transmitters operate at peak powers of 100–4000 kilowatts, comparable to longwave broadcasting stations. Most use 190–220 metre tall mast radiators, insulated from ground. The masts are inductively lengthened and fed by a loading coil (see: electrical lengthening). A well known-example of a station using such an antenna is Rantum. Free-standing tower radiators in this height range are also used. Carolina Beach uses a free-standing antenna tower. Some LORAN-C transmitters with output powers of 1000 kW and higher used supertall 412 metre mast radiators (see below). Other high power LORAN-C stations, like George, used four T-antennas mounted on four guyed masts arranged in a square.
All LORAN-C antennas are designed to radiate an omnidirectional pattern. Unlike longwave broadcasting stations, LORAN-C stations cannot use backup antennas because the exact position of the antenna is a part of the navigation calculation. The slightly different physical location of a backup antenna would produce Lines of Position different from those of the primary antenna.
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