The Secretary of State to the Ambassador in Mexico ( Daniels )

No. 603

Sir: The Department is informed by the Federal Communications Commission, in a letter dated January 22, 1935,69 that recent reports [Page 807] received by the Commission, as well as independent observations made by the Commission’s Monitoring Station at Grand Island, Nebraska, make it evident that a very serious problem is developing in relation to interference in the amateur frequency bands 3500–4000 kilocycles, 7000–7300 kilocycles, and 14000–14400 kilocycles, as a result of the operation in these bands of amateur radiotelephone stations in Mexico.

The Commission states that inasmuch as the interference in question is sometimes so severe as to blanket large portions of the frequency bands mentioned, the effectiveness of amateur radio in North America as a whole, and particularly in the United States in which there are approximately 46000 licensed amateur radio operators, is seriously impaired.

Under the provisions of the Washington Radiotelegraph Convention, 1927,70 and the General Regulations annexed thereto, to which both the United States of America and Mexico are parties, as well as under the provisions of the Madrid Telecommunication Convention, 1932,71 and the General Radio Regulations annexed thereto, the frequency bands above mentioned may be used by all classes of amateur stations. The Commission states, however, that because of the large number of stations in the world using these frequency bands, primarily for long distance communications, it has become a general practice in North America for amateur radiotelephone to use the frequency bands 1800–2000 kilocycles, 3900–4000 kilocycles, 14150–14250 kilocycles, 28000–28500 kilocycles, 56000–60000 kilocycles, and 400000–401000 kilocycles. In the United States this practice has been made mandatory under sections 376 and 377 of the Rules and Regulations of the Federal Communications Commission,72 which read as follows:

“376. The following bands of frequencies are allocated for use by amateur stations using radiotelephony, type A–3 emission:

1,800 to 2,000 kilocycles 56,000 to 60,000 kilocycles
28,000 to 28,500 kilocycles 400,000 to 401,000 kilocycles

“377. Provided the station shall be operated by a person who holds an amateur operator’s license endorsed for class A privileges, an amateur radio station may use radiotelephony, type A–3 emission, in the following additional bands of frequencies:

3,900 to 4,000 kilocycles 14,150 to 14,250 kilocycles.”

It is considered that a similar practice in Mexico, restricting amateur radiotelephone to the frequency bands last mentioned and permitting only type A–l emissions in the frequency bands 3500–3900 kilocycles, [Page 808] 7000–7300 kilocycles, 14000–14150 kilocycles, and 14250–14400 kilocycles, would be desirable with a view to preserving the effectiveness of the amateur bands and preventing interference conditions in these bands from becoming intolerable.

It is contemplated by the provisions of the conventions referred to above that the contracting Governments shall undertake to aid each other by supplying information concerning means of improving the various services and of preventing or eliminating radio interference. It is requested, therefore, that you bring this matter to the attention of the appropriate authorities of the Mexican Government, and that you ascertain and inform the Department of the attitude of the Mexican Government in this connection.

Very truly yours,

For the Secretary of State:
R. Walton Moore
  1. Not printed.
  2. Foreign Relations, 1927, vol. i, p. 288.
  3. Ibid., 1932, vol. i, p. 873.
  4. U. S. Federal Radio Commission, Rules and Regulations (Washington, Government Printing Office, 1934), p. 128.