UHF CB

Many UHF CB radios allow the user to scan channels to find a conversation. Several different scan modes may be provided:

Open Scan scans all 80 channels to find an active conversation. Some radios allow skipping selected channels when scanning.

Group Scan scans a small number of selected channels. For example, a caravanner travelling around the country may choose to group scan Channel 40 (Road Channel), 18 (Caravan Channel) and 5 (Emergency Channel) so they will hear any conversations relating to their travels.

Priority Scan allows selection of a "priority" channel whilst scanning a handful of selected channels. This could be useful in a convoy of cars where vehicles can set their own convoy channel as a priority channel whilst scanning the designated road channel for traffic updates, if a member from their convoy speaks, the radio will always switch back to the priority channel even if someone is speaking on another channel.

Selective calling (Selcall) allows a 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. The popularity of selcall has dropped since the introduction of 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.

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. Repeaters are on channels 1–8 and 41–48 and the duplex button should be pressed to access the repeater.[4]

It is common practice to install signs at the rear of camper vans and caravans, worksites, roadworks, regional highways, national parks and heavy vehicle checking stations to advertise a UHF channel to communicate on. For example, during the widening of the M1 Pacific Motorway between Sydney and Newcastle, contractors installed "UHF 29" signs at the entry point to each worksite.

New Zealand offers a similar PRS service. New Zealand's Personal Radio Service (PRS) and 26 MHz Citizens Band radio are very similar to Australia's UHF Citizens Band and 27 MHz Citizens Band services.

The New Zealand Government's Ministry of Commerce introduced the UHF PRS in 1996 to allow for freely available short-range wireless communications outside the 26 MHz CB band. The UHF (but not VHF) band was selected due to its ability to withstand atmospheric and groundwave interference unlike the existing 26 MHz allocation.

NZ PRS channels

• http://www.uhfcb.com.au/NZ-PRS-Channels.php

• Citizens band radio
• VMB4 Newcastle - An example of an Australian UHF CB Repeater

• Radiocommunications (Citizen Band Radio Stations) Class Licence 2015 - The Australian official licence under which UHF CB operates
• Australian Communications and Media Authority - The Australian regulator of the radio-frequency spectrum
• Tropinet UHF CB Repeater Database for a listing of repeaters in Australia.