The general rule of thumb when it comes to RF aerials is the higher the frequency the smaller the booster antenna
A good example is the antenna size of a mobile phone, which uses nearly twice the frequency of a UHF Radio.
Good booster antenna performance is important because it can assist your reception and transmission greatly whether it be VHF radio, AM CB radio, UHF radio, cellular or GPS systems...
Booster antennas are also made to have gain, which will increase the Effective Radiated Power (ERP) of your RF radio.
The UHF wavelength of 477MHz is around 62cm and the length of the antenna is very critical. This is the main reason why many 477MHz “Whips” usually come out of the factory pre-tuned. The most basic type of whip antenna is the quarter wave ground plane, which are about 15cm in length and are made of stainless steel or wire, for more flexibility. These relatively small antennas have a naturally high angle of radiation and are best used in hilly countryside. They work well with repeaters because they are ideal for carrying the signal from a low point such as your vehicle to a high point where the repeater may be situated.