for the high quality wideband FM transmissions. The long wave band is not available for broadcasting in all areas of the world, although the medium wave band is a worldwide allocation. In view of the quality which can be attained this modifies the nature of the broadcasting. In areas where the stations are competing with FM services the medium wave tends to have a high percentage of speech-based programming. However, this does not mean that music programming is Broadcasting 205 not present, although stations using the medium wave band are finding that listeners are migrating to the high quality FM broadcasts. A variety of transmitter powers are used. In the UK, for example, the BBC operates a number of national networks. There are also independent national networks as well. Transmitters for these run many kilowatts and can be heard over large distances. In addition to these there are many local stations. These are only intended to have a relatively small coverage area and the transmitters may only run 100 watts or SO. In North America it is normal for transmitters to be reduced in power at night when propagation via the ionosphere is possible. In recent years the broadcast bands have been standardized SO that stations transmit on particular channels. The channel spacing on the medium wave band is 9kHz in Europe and kHz in the USA. This reduces the amount of interference because the number of annoying heterodynes from stations 1 or 2 kilohertz away from one another are eliminated. Although many new forms of broadcasting are available these days short wave broadcasting is still very popular. It is cheap to receive the transmissions as short wave radios are widely available for reasonable prices and many people, especially those in remote areas, still use this means for reception. In countries in Europe and North America other forms of broadcasting are more widely used and short wave reception is mainly by enthusiasts. On the short wave bands stations are almost exclusively used for international broadcasting. Becau