Dual Watch; Using Repeater Channels - Uniden UH7760NB Owner's Manual

Operation

DUAL Watch

Dual watch will continuously monitor the Instant channel no matter what
other channel is on (see Programming the Instant Priority Channel above).
Press and hold [DCS/CTCSS/DUAL]. DUAL icon appears and a short
tone beep is heard.
To cancel DUAL Watch press and hold [DCS/CTCSS/DUAL]. DUAL icon
disappears.

Using Repeater Channels

UHF CB repeaters are used to retransmit or relay your signal. Repeaters
will extend the range of your radio and overcome the shielding effect
caused by solid obstructions. In normal Simplex operation, your radio
transmits on one particular frequency and receives on that same
frequency.
If there is a barrier that partially blocks your transmitted signal, the
probability of another radio receiving the signal is very slim. Hills, tall
buildings, metallic structures,...etc tend to act as a screen between radios.
Standard Operation without the aid of a Repeater station.
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UNIDEN UH7760NB UHF CB Transceiver