2. UHF (Ultra High Frequency) at 403-470 MHz. Best Suited For: Indoor applications or environments with obstructions and typically used for city two way radio systems.
UHF CB or citizen band radio is a two-way radio system that uses the 476.4250–477.4125MHz, radio spectrum for short-distance communications.
You can find the frequencies for CB radios in schedule 1 of the class licence . You can only use CB radios on designated channels in these frequencies: HF – 26.965 MHz to 27.405 MHz (inclusive) UHF – 476.4125 to 477.4125 MHz (inclusive)
UHF (Ultra High Frequency) frequency band
UHF radio signals are those on frequencies from 300MHz - 3000MHz.
27 MHz AM/SSB allocations are similar across countries though some places also allow FM. Larger differences apply on UHF. Australia and New Zealand have 477 MHz UHF CB. Europe has PMR on 446 MHz and the USA Family Radio Service on 462/467 MHz.
433MHz transmitters are legal to use in Australia without any form of licensing up to 25mW. It is why virtually every garage door opener is (legally) in this range.
Channel 40 commonly used by truck or oversized vehicle drivers: This channel is Australia's main road safety resource.
Lightweight and robust, uhf satcom provides a highly secure means of communication with extensive uses on land, at sea and in the air to meet the needs of the armed forced. satcom antenna have a monogamous relationship with satellites in that they only talk to one antenna.
UHF vs VHF – Advantages and Disadvantages
UHF, with its higher frequencies and shorter wavelengths, will penetrate structures better than VHF so it should be used any time a user needs to communicate indoors, especially when trying to talk thru reinforced concrete structures.
Since UHF transmission is limited by the visual horizon to 30–40 miles (48–64 km) and usually to shorter distances by local terrain, it allows the same frequency channels to be reused by other users in neighboring geographic areas (frequency reuse).
Two-way radios offer closed communication networks and these networks are known to be difficult for hackers to access. The networks rely on radio frequency, not an internet connection and radio frequencies can be hard to trace through GPS but it's not impossible.
The accepted 'Highway Channel' used by most truck drivers throughout Australia is Channel 40. However, if travelling on the Pacific Highway and Pacific Motorway in northern NSW and southern Queensland you may find channel 29 is used more frequently by truck drivers and others travelling in that area.
Most truckers use the unofficial channel 19 (27.185 MHz) to communicate. This channel offers highway traffic information from truckers and other drivers.
When choosing an antenna you want to make sure it's going to be effective for your UHF needs and not just look good on the bull bar. Antenna gain is measured in dBi and is simply the measure of an antenna's ability to direct or concentrate radio frequency energy in a particular pattern or direction.
VHF radio (Very High Frequency)
VHF radios offer a larger broadcast range, using radio waves from 30 MHz to 300 MHz.
There are 80 Channels of free UHF CB Two Way Radio Channels that have been set aside for the general public to use. These frequencies are in the UHF Band between 476.4250 and 477.4125 MHz. Any frequencies outside of this band are for COMMERCIAL USE ONLY and all need to be licenced.
Comparing two waves of the same wavelength, a higher frequency is associated with faster movement. Comparing two waves of different wavelengths, a higher frequency doesn't always indicate faster movement, although it can. Waves of different wavelengths can have the same frequency.
The amount of energy they carry is related to their frequency and their amplitude. The higher the frequency, the more energy, and the higher the amplitude, the more energy.
"RF [radio frequency] signals can travel through obstructions such as walls, trees and smoke, while optical and infrared imaging systems cannot," the engineers wrote.
UHF (ultra high frequency) radios operate on higher frequencies. These frequencies are able to penetrate through buildings, including materials such as steel and concrete. This makes UHF radios ideal for indoor use.
VHF radio signals are on the low end of the frequency scale when compared to UHF. Although, VHF signal wavelength is longer, allowing it to travel farther than UHF.
Both UHF and VHF radios are used in flight communication, for different aspects of flight. VHF radio is still the go-to frequency for many aspects of aircraft, with a group of VHF frequencies set aside as aircraft band frequencies, which means they are solely for use by civil aviation professionals.
Frequencies and Licensing
It is a Federal offence to transmit on any frequency without a license except for the UHF CB frequencies. All frequencies within each band are required to have licenses except the UHF CB, as these are designated for Public use.
It's not illegal to use a UHF or CB radio while driving
That means, if a police officer pulls you over for erratic driving and spotted you using your UHF or CB radio and decides that is the culprit then you can be fined for not being in proper control of a motor vehicle.