Tape position

from Wikipedia, the free encyclopedia
Simple radio network with relay station

With the radio traffic type " two-way communication (duplex) ", each channel has two frequencies , one in the upper band (here the relay station transmits) and one in the lower band (here the mobile subscriber transmits). Radio devices equipped with a duplex switch allow simultaneous sending and receiving ( full duplex operation ), since both participants use their own frequencies. Any control center connected to the relay station via a radio link can interrupt the mobile subscriber, it has a priority circuit.

The mobile radio subscribers receive each other in ( semi or half duplex operation or conditional two- way communication or two-frequency simplex ) so that the subscribers can only send alternately , as in simplex operation .

In German BOS radio , most mobile subscribers use a duplex switch , but due to their size, the handheld radios can only work with a simple antenna switch between the transmitter and receiver. The duplex capability increases operational safety, as the radio operator can hear his echo through the relay station.

The frequency offset , also referred to as band or duplex spacing , is 9.8 MHz in the 4 meter band , for example , and the channel spacing in this range is 20 kHz .

For example, if a subscriber sends on the lower band and receives on the upper band, one speaks of "double talk lower band" (GU), but if he sends on the upper band then this is called "double talk upper band" (GO).