The UK channels that were legalised on 2 November 1981 were on two blocks of frequencies: 40 channels on the 27 MHz band and 20 channels on the 934 MHz band, both of which used FM (frequency modulation) and both unique to the UK. The 27 MHz band frequency allocation and related information is shown here. In 1987 40 additional frequencies were added, which were the same as the US allocation – but again using FM. This additional band is often referred to as the CEPT or EU band. As with the original 40 channels, this band is affected by the same atmospheric characteristics, especially towards the maxima of the 11-year sunspot cycle.