Monthly Archive August 28, 2021

Avatar Bywouxuncom

What is UHF CB Two Way Radio?

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. 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.

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 (handy 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.

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.