Public air-ground telephone service trial

While radio communication to airplanes has been in everyday use for many years, until September 15, 1957, the only public telephone service available to aircraft has been that furnished through coast stations which have been established for the provision of telephone service to ships. Approximately 600 aircraft are registered for service through coast stations operating in the 2-mc (megacycle) frequency range. The service is not satisfactory in many respects. It is not available in many inland areas and due to the crowded conditions on the marine channels fast-moving aircraft are frequently unable to receive any service before landing at their destination. In addition, atmospheric noise at these frequencies seriously limits the range and reliability of the service. Even with these limitations the service has grown as shown in Fig. 1.