The Wireless Museum has several of the earliest crystal wireless sets from the 1920s which ran on electromagnetic waves with no external power source, and were easily made at home. Valve radios, which came along in the 1930s, needed electricity to heat up the valves and the museum has both mains and battery-powered valve radios on display. The collection also has some rare wartime civilian receivers — the only type of valve radio manufactured during the Second World War. This was by order of the government, because at this time most manufacturing was focused on the war effort. There are also plenty of modern day transistor radios including a collection of novelty radios dating from the sixties and seventies.