Crossband (cross-band, cross band) operation is a method of

telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

in which a radio station receives signals on one

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...

and simultaneously transmits on another for the purpose of full duplex communication or signal relay. To avoid interference within the equipment at the station, the two frequencies used need to be separated, and ideally on different 'bands'. An unattended station working in this way is a

radio repeater A radio repeater is a combination of a radio receiver and a radio transmitter that receives a signal and retransmits it, so that two-way radio signals can cover longer distances. A repeater sited at a high elevation can allow two mobile stations, ...

. It re-transmits the same information that it receives. This principle is used by

telecommunications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...

s and

terrestrial mobile radio Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

systems.

Uses

Crossband operation is sometimes used by

amateur radio Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communic ...

operators.Crossband Repeater Operation, C. LaBarge (WB3GCK) http://www.qsl.net/wb3gck/cbr.htm Rather than taking it in turns to transmit on the same frequency, both operators can transmit at the same time but on different bands, each one listening to the frequency that the other is using to transmit. A variation on this procedure includes establishing contact on one frequency and then changing to a pair of other frequencies to exchange messages. Crossband operation is also used in communication between ships (intership) with a HF installation. Frequencies that may be used can be found in the 'Manual for use by the Maritime Mobile and Maritime Mobile-Satellite Services'. Usually intership communication is simplex only (VHF or MF), HF gives the possibility to work duplex but usually the transmitter and receiver are so close to each other that this may cause problems. The solution is to work on frequencies that are far apart e.g.: sending on 8 MHz and receiving on 12 MHz.

Uses

See also

References

Further reading