what are uhf repeater channels?
Channels 1 to 8 (and 31 to 38) are for repeaters. (these are sometimes called DUPLEX use) Each repeater needs a pair of channels to work. When on channel 1 repeater, channel 31 is also used up, 2 uses 32 – and 3 uses 33 – etc. Avoid channels 31 to 38 for general use.