That the right to use such stations for any of the purposes named . . . shall terminate and cease as between any countries or localities or between any locality and privately operated ships, whenever privately owned and operated stations are capable of meeting the normal communication requirements between such countries or localities or between any locality and privately operated ships, and the Secretary of Commerce shall have notified the Secretary of the Navy thereof . . .During 1920 the commercial companies established stations at principal U.S. ports to provide ship-shore radio communication facilities. There were numerous locations where the anticipated revenues were not sufficient to interest them, and the Navy continued to provide the required facilities as well as those for isolated localities which required point-to-point radio communications in a volume insufficient to warrant commercial interest. Additionally, Public Law No. 264 prohibited commercial radio operations within the Canal Zone. Many of these circuits were provided by the Naval Communication System on a scheduled basis.
In 1924 the commercial companies commenced the use of higher frequencies which allowed coverage of larger ocean areas by their coastal stations, and from that time there was a gradual diminution of the assistance needed from naval radio stations.
Tutuila. Apia, British Samoa.
Cavite. Hanoi, French Indochina.
Malabar, Dutch East Indies.
Balboa. Puerto Barrios, Guatemala.
Limón, Costa Rica.
Bragman's Bluff, Nicaragua.
Cape Gracias, Nicaragua.
Belize, British Honduras.
Santa Marto, Colombia.
San Juan. Curacao.
Port-au-Prince. Santo Domingo. Guantanamo. Kingston, Jamaica. St. Thomas. Curacao.
High-powered stations, capable of transmitting at least 3,000 miles, located at strategic points in the United States and its possessions to insure communications with the fleet in any part of the world and for intercommunications with similar adjacent ones. They were not normally used for direct communications with ships, but transmitted messages to fleet units by broadcasting, utilizing either the intercept or the no-answer method.4 These stations were equipped with arc equipments emitting only waves.All stations were connected with their own district centers either by landline or radio. In many cases the transmitting stations were keyed by landline and the receiving done at the district center via monitor stations and tone channels. Each high-powered station included a medium-powered one and, likewise, each medium-powered station included a low-powered one to insure a completely integrated system.
Medium-powered stations, capable of transmitting at least 1,000 miles, for the purpose of connecting adjacent naval districts and to provide long-distance ship-shore service. These stations also used the intercept and no-answer broadcast methods and were equipped with medium-powered arc equipment emitting only continuous waves.
Low-powered stations, with transmission ranges of less than 1,000 miles, situated along the coast to provide close-in ship-shore service and communications with the naval district headquarters, the location of the district communications center. These stations were normally provided with low-powered arcs equipped with choppers, or with spark transmitters.