Caravan, c. 1935, fitted with public address equipment by Cecil Clarabut, c. 1938,

This caravan was owned by Cecil Clarabut, who was the founding Chairman of the Association of Public Address Engineers, and a pioneer in the public address field. The first outside broadcast was probably by Peter L Jensen and Edwin Pridham in December 1915 with something they called the Magnavox, and in 1919 United States President Woodrow Wilson used a Magnavox system to address a crowd in San Diego. In the twenties the technology started to come over to Britain and was championed by the Marconi Company. In 1925 this technology received massive publicity when King George V used it to address 90,000 people at the opening of the Wembley Exhibition.