Here is a first day cover from the International Telecommunications Conference of 1938 held in Cairo, Egypt. It was at this conference that the shortwave broadcasting bands were expanded, resulting in the authorization of shortwave broadcasting on these familiar frequencies: 6.0-6.2, 7.2-7.3, 9.5-9.7, 11.7-11.9, 15.1-15.35, 17.75-17.85, 21.45-21.75 and 25.6-26.6 megacycles.