UHF CB

UHF CB is a class-licensed citizen's band radio service authorised by the governments of Australia, New Zealand, Vanuatu, and Malaysia in the UHF 477 MHz band.[1] UHF CB provides 77 channels, including 32 channels (16 output, 16 input) allocated to repeater stations. It is similar in concept to 27 MHz CB Radio in the United States, Australia, and New Zealand.

Class licensing means that users do not have to apply for a licence or pay a licence fee however they must comply with the regulations of the class licence.[2]

User equipment designs are similar to commercial land mobile two-way radio except the maximum legal output power is 5 Watts. External antennas are permitted and commercially manufactured antennas have gains as high as 12 dB. Handheld transceivers (walkie talkies) are permitted and have transmit power from 500 mW to 5 W (full legal power) and are relatively cheap compared to full-sized transceivers. Operation in the band is restricted to modes F3E and G3E (FM or PM of analogue voice telephony) except for channels 22 and 23, which are data modes only.[3]

It is illegal to use non-standard radios purchased from overseas because they interfere with licensed land-mobile services. This includes overseas personal radio service devices because they do not share the same band plan, power output and channels as UHF CB. Care must be taken when importing radios from overseas to ensure they comply with local regulations. Approved radios are identified by an Australian standards C Tick usually found on the tag or sticker of the radio.

Scan

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.

Selcall

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.

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

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]

Signage

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.

Channel use

Legally restricted channels

The following channels are legislated as a part of the ACMA UHF CB Class Licence.[5]

  • Channel 5 and 35 are the designated emergency channels in Australia, Vanuatu and Malaysia, and are not to be used except in an emergency. Making an emergency call involves switching the radio to Channel 5 with duplex on, and trying again with duplex off if there's no response. In New Zealand channels 5 and 35 are not emergency channels, they are available for general use in duplex (repeater) mode. In New Zealand, if you use UHF PRS for emergency, you rely on someone listening on the same channel. Scan all channels for activity before requesting assistance.
  • Channel 9 is the designated emergency channel in Malaysia.
  • 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.
  • 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

The following channels are not legislated as a part of the class licence however are used for the following purposes by consensus.

  • Channel 10 is typically used by 4WD clubs when in a convoy and in national parks. This channel is used to avoid interfering with road safety communications on channel 29 or 40. If you are not in a convoy it is recommended that only 29 or 40 are used, depending on the road in question.
  • Channel 18 is the campers and caravan convoy channel typically used by travellers.
  • Channel 29 is the road safety channel on the M1 Pacific Motorway and Highway between Tweed Heads and Newcastle in NSW. It is used due to one transport company who travelled this road who always used this channel. Other drivers switched from 40 to 29 to talk to them and it became a custom. This custom prevails even though the original transport company no longer exists.
  • Channel 40 is the primary road safety channel Australia-wide, most commonly used by trucks including pilot/escort vehicles for oversized loads.[6][7]

Users should be aware that UHF CB channels 31 to 38 and 71 to 78 are the 'input' channels for repeaters. Users should avoid using these channels to avoid interfering with repeaters. If a repeater is to be used, switch to 1–8 or 41–48 and press the duplex button.

UHF CB band plan

Expansion to 80 channels

On 27 May 2011 the channel spacing on UHF CB was changed, allowing the band to expand from 40 channels to 80 channels.[8] Due to data channels 22 and 23 occupying 25 kHz bandwidth, the expansion effectively allows the use of 77 channels, as channels 61, 62 and 63 are reserved.

ACMA originally intended to make older 40 channel UHF radios on the 25kHz spacing illegal to use from June 2017. However, in February 2017, it reversed this decision after determining that the two systems were working well alongside each other.[9]

Current UHF CB band plan (80 Channels)

General chat channels are used in simplex mode, repeater channels must be used in duplex mode. If you are not using a repeater it is recommended to choose a "general chat" channel.

Channel Name:Frequency:Purpose:Frequency Spacing:
Channel 1476.4250Repeater Channel12.5 kHz
Channel 2476.4500Repeater Channel12.5 kHz
Channel 3476.4750Repeater Channel12.5 kHz
Channel 4476.5000Repeater Channel12.5 kHz
Channel 5476.5250Emergency Repeater Output (not an emergency channel in New Zealand)12.5 kHz
Channel 6476.5500Repeater Channel12.5 kHz
Channel 7476.5750Repeater Channel12.5 kHz
Channel 8476.6000Repeater Channel12.5 kHz
Channel 9476.6250General Chat Channel12.5 kHz
Channel 10476.65004WD Clubs or Convoys and National Parks.12.5 kHz
Channel 11476.6750Call Channel12.5 kHz
Channel 12476.7000General Chat Channel12.5 kHz
Channel 13476.7250General Chat Channel12.5 kHz
Channel 14476.7500General Chat Channel12.5 kHz
Channel 15476.7750General Chat Channel12.5 kHz
Channel 16476.8000General Chat Channel12.5 kHz
Channel 17476.8250General Chat Channel12.5 kHz
Channel 18476.8500Caravanners and Campers Convoy Channel12.5 kHz
Channel 19476.8750General Chat Channel12.5 kHz
Channel 20476.9000General Chat Channel12.5 kHz
Channel 21476.9250General Chat Channel12.5 kHz
Channel 22476.9500Telemetry and Telecommand Only (No Voice or Data)25 kHz
Channel 23476.9750Telemetry and Telecommand Only (No Voice or Data)25 kHz
Channel 24477.0000General Chat Channel12.5 kHz
Channel 25477.0250General Chat Channel12.5 kHz
Channel 26477.0500General Chat Channel12.5 kHz
Channel 27477.0750General Chat Channel12.5 kHz
Channel 28477.1000General Chat Channel12.5 kHz
Channel 29477.1250Road Safety Channel

Pacific Hwy/Mwy between Brisbane (QLD) and Sydney (NSW)

12.5 kHz
Channel 30477.1500General Chat Channel12.5 kHz
Channel 31477.1750Repeater Input12.5 kHz
Channel 32477.2000Repeater Input12.5 kHz
Channel 33477.2250Repeater Input12.5 kHz
Channel 34477.2500Repeater Input12.5 kHz
Channel 35477.2750Emergency Repeater Input (not an emergency channel in New Zealand)12.5 kHz
Channel 36477.3000Repeater Input12.5 kHz
Channel 37477.3250Repeater Input12.5 kHz
Channel 38477.3500Repeater Input12.5 kHz
Channel 39477.3750General Chat Channel12.5 kHz
Channel 40477.4000Road Safety Channel Australia Wide12.5 kHz
Channel 41476.4375Repeater Channel12.5 kHz
Channel 42476.4625Repeater Channel12.5 kHz
Channel 43476.4875Repeater Channel12.5 kHz
Channel 44476.5125Repeater Channel12.5 kHz
Channel 45476.5375Repeater Channel12.5 kHz
Channel 46476.5625Repeater Channel12.5 kHz
Channel 47476.5875Repeater Channel12.5 kHz
Channel 48476.6125Repeater Channel12.5 kHz
Channel 49476.6375General Chat Channel12.5 kHz
Channel 50476.6625General Chat Channel12.5 kHz
Channel 51476.6875General Chat Channel12.5 kHz
Channel 52476.7125General Chat Channel12.5 kHz
Channel 53476.7375General Chat Channel12.5 kHz
Channel 54476.7625General Chat Channel12.5 kHz
Channel 55476.7875General Chat Channel12.5 kHz
Channel 56476.8125General Chat Channel12.5 kHz
Channel 57476.8375General Chat Channel12.5 kHz
Channel 58476.8625General Chat Channel12.5 kHz
Channel 59476.8875General Chat Channel12.5 kHz
Channel 60476.9125General Chat Channel12.5 kHz
Channel 61476.9375Reserved for Future Expansion-
Channel 62476.9625Reserved for Future Expansion-
Channel 63476.9875Reserved for Future Expansion-
Channel 64477.0125General Chat Channel12.5 kHz
Channel 65477.0375General Chat Channel12.5 kHz
Channel 66477.0625General Chat Channel12.5 kHz
Channel 67477.0875General Chat Channel12.5 kHz
Channel 68477.1125General Chat Channel12.5 kHz
Channel 69477.1375General Chat Channel12.5 kHz
Channel 70477.1625General Chat Channel12.5 kHz
Channel 71477.1875Repeater Input12.5 kHz
Channel 72477.2125Repeater Input12.5 kHz
Channel 73477.2375Repeater Input12.5 kHz
Channel 74477.2625Repeater Input12.5 kHz
Channel 75477.2875Repeater Input12.5 kHz
Channel 76477.3125Repeater Input12.5 kHz
Channel 77477.3375Repeater Input12.5 kHz
Channel 78477.3625Repeater Input12.5 kHz
Channel 79477.3875General Chat Channel12.5 kHz
Channel 80477.4125General Chat Channel12.5 kHz

New Zealand

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

gollark: If it was federated and open, people would be able to move off it more easily.
gollark: That would reduce their ability to data-mine this like crazy, which I assume is how they aim to monetize it eventually.
gollark: I've looked at XMPP, but I'm not sure if that works for chatroom-type things or just person/person messaging.
gollark: I would really prefer to be using some sort of open federated messaging service, but that would be more annoying for people to use I guess.
gollark: Curse Discord and being required by the ToS to only use their kind of awful clients!

See also


References
  1. Jim Sinclair Radio Signal Finding McGraw-Hill Professional, 2000 ISBN 0-07-137191-5 page 281
  2. http://www.acma.gov.au/Citizen/TV-Radio/Radio/Marine-and-Amateur-Radio/citizen-band-radio-service-cbrs-fact-sheet
  3. https://www.legislation.gov.au/Latest/F2015L00876
  4. http://www.uhfcb.com.au/CB-Radio-History.php CB radio History
  5. https://www.legislation.gov.au/Latest/F2015L00876
  6. https://www.mainroads.wa.gov.au/Documents/Final%20PDF%20version%20-%20OSOM%20Loads%5E2C%20Pilots%20and%20Escort%20vehicles%20brochure.RCN-D13%5E23398873.PDF
  7. http://www.police.qld.gov.au/Resources/Internet/rti/policies/documents/Circular%202-2014.pdf
  8. http://www.acma.gov.au/WEB/STANDARD/pc=PC_287
  9. Claughton, David (3 February 2017). "Peak communications body ACMA reverses decision ruling thousands of CB radio sets illegal". ABC Rural. Australian Broadcasting Corporation. Retrieved 8 June 2020.
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