the computer transmitter being used. Reserved frequencies Many countries reserve specific frequency bands (ranges) for radio-control use. Due to the longer range and potentially worse consequences of radio interference, model aircraft have exclusive use of their own frequency allocation in some countries. USA and Canada reserved VHF frequency bands 72 MHz: aircraft only (France also uses US/Canada channels 21 through 35). 75 MHz: surface vehicles. 53 MHz: all vehicles, only for older equipment on 100 kHz spacing, with the operator holding a valid amateur radio (FCC in the USA) license. The 53 MHz band began to become vulnerable to amateur radio repeater stations operating on the 53 MHz area of the 6-meter band during the early 1980s. The 53 MHz bands can still be used with relative safety for ground-based (cars, boats/ships) powered modeling activities. 50.8 to 51 MHz: on the 6-meter band for all vehicles at 20 kHz spacing, with the operator holding a valid amateur radio (FCC in the USA) license. Added in the 1980s as the amateur radio repeater interference problem on the earlier 53 MHz bands in the United States began to manifest itself. 27 MHz: first band opened for RC use in the United States and shared with CB radio users: as with 53 MHz for Hams, nowadays preferable for use on ground-based RC models only — also used for older RC toys before 1991. USA and Canada reserved UHF frequency bands 2.400-2.485 GHz: 13-cm UHF Spread Spectrum band for general use (amateur radio license holders have 2.39-2.45 GHz licensed for their general use in the USA) and using both frequency-hopping spread spectrum and direct-sequence spread spectrum RF technology to maximize the number of available frequencies on this band, especially at organized events in North America. US frequency chart available at , Canadian frequency chart available at European reserved VHF & UHF frequency bands 35 MHz: aircraft only. 40 MHz: surface vehicles or aircraft. 27 MHz: general use, toys, citizens band radio. 2.4 GHz 13-cm UHF band spread spectrum: surface vehicles, boats and aircraft. Within the 35 MHz range, there are designated A and B bands. Some European countries allow use only in the A band, whereas others allow use in both bands. United Kingdom reserved frequency bands 458.5–459.5 MHz: low-UHF band for surface vehicles or aircraft. (Non-Ham-frequencies 70-cm amateur band in the UK covers 430-440 MHz) Singapore reserved frequency bands 72 MHz: aircraft only