UHF Radios

uniden uh7760nb

Redlands 4WD Centre stocks the ever popular range of Uniden UHF’s

For more information on these units please visit www.uniden.com.au

A few things to help you get started on UHF Radios

Repeaters

Repeaters extend the range of transmission by receiving and automatically rebroadcasting a transmission using an antenna located in a high location, normally the top of a mountain, tall building or radio tower. Sometimes a transmission range of over 100 kilometres (60 miles) can be achieved through the use of a repeater. The repeater function on a UHF CB radio is normally referred to as ‘duplex’ or a ‘range extender’ function.

Channel use

Whilst some channels are legally restricted in how they may be used (such as emergency channels), there is a consensus on how some of these channels are used depending on conversations or situations, but which are not officially recognised in the class licence.

Legally restricted channels

  • Channel 5 and 35 are the designated emergency channels, and are not to be used except in an emergency. These channels are monitored by volunteers.
  • Channel 11 is the ‘call channel’ and is only to be used for initiating calls with another person, who should quickly organise another vacant channel to continue their discussion on.
  • Channel 22 and 23 are only to be used for telemetry and telecommand, packet data and voice transmission are not allowed.
  • Channel 61, 62 and 63 are reserved for future allocation and transmission on these channels is not allowed.

Channels used by consensus

  • Channels 10 & 16 are typically used for 4WD convoy, clubs and national parks.
  • Channel 18 is the campers and caravan convoy channel, typically used by travelers.
  • Channel 40 is often used for communicating with road users, including pilot/escort vehicles for oversized loads.

Users should be aware that UHF CB channels 31 to 38 and 71 to 78 are the ‘input’ channels for repeaters on channels 1 to 8 and 41 to 48, and should avoid using these channels in simplex mode where they are in range of a repeater, to avoid interfering with it.

Selective calling (Selcall)

Selective calling (Selcall) allows an individual radio to call another radio using a sequence of tones, usually presented to the user as a series of 5 numbers. UHF CB radios can be set to be completely silent until they receive a series of tones matching a pre-programmed sequence. Radios which have this feature usually indicate that a call has been received by emitting a number of beeps and by opening the squelch.

Continuous Tone Coded Squelch System (CTCSS)

Continuous Tone Coded Squelch System (CTCSS) allows a group of radios set with the same tone to converse on a channel without hearing other radios using that channel. CTCSS can be used to silence a radio until another radio with the same tone transmits. This allows monitoring of a channel for transmissions from radios set with the same tone without hearing other conversations that use different or even no tone.

The use of CTCSS is not permitted on UHF CB repeaters or the designated emergency channels.