INTERNATIONAL AGREEMENTS OTHER THAN TREATIES [54 STAT. the transmitter should not be modulated in excess of its modulation capability to the extent that interfering spurious radiations occur and in the case of amplitude modulation the operation percentage of modulation should not be less than 75 per cent on peaks of frequent recurrence. Adequate means should be employed to insure that the transmitter is not modulated in excess of its modulation capability. A spurious radiation is any radiation from a transmitter which is outside the frequency band of emission normal for the type of trans- mission employed, including any harmonic modulation products, key clicks, parasitic oscillations or other transient effects. SECTION 5. NON USE OF 333 Kc/s. AS AIR CALLING FREQUENCY. 49 stat. 2471. Referring to Article 7, Paragraph 11 of the Madrid Radiocom- munications the frequency 333 kc/s. is not to be used as an inter- national Air Calling frequency in the American Continent, except in special cases in connection with transatlantic flights. SECTION 6. USE OF 500 Kc/s. Referring to Article 19, Section I, Paragraph 6-a of the Madrid 49 Stat. 2516 . Radio Regulations, the entire American Continent, except for Hudson Bay and Regions North thereof, shall be considered a region of heavy traffic within the meaning of said Article, therefore, except for Hudson Bay and Regions North thereof, traffic on 500 kc/s. shall be limited to the transmission of distress traffic, urgent and safety messages, signals and single short radio telegrams. SECTION 7. DEFINITIONS 1 DEFINITION OF TERMS Defintions. The definitions of terms which appear as numbers (1) to (42) inclusive of Section XII of Resolution No. 6 of the Final Act of the March 1937 Conference of Habana, are approved with the reservation that any changes which may result from the International Radio Ante, p . 1419. Conference of Cairo 1938, with respect to the wording of these defini- tions shall automatically supersede the present wording. (1) TELECOMMUNICATION: Any telegraph or telephone communication of signs, signals, writing, images and sounds of any nature, by wire, radio, or other systems or processes of electrical or visual (semaphore) signalling. (2) RADIOCOMMUNICATION: Any telecommunication by means of Hertzian waves. (3) RADIOTELEGRAM: Telegram originating in or destined to a mobile station, transmitted on all or part of its route over the radio channels of the mobile service. [Modified by the Cairo, 1938, revuson (Treaty ries 948).] 2524
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