2532 INTERNATIONAL AGREEMENTS OTHER THAN TREATIES [54 STAT. f) the standardization which therefore seems desirable in order to facilitate international flying by coordination, and, as far as pos- sible, standardization of equipment and operating procedure; g) that it is possible for a single ground station such for instance as the radio range beacon to simultaneously give navigational guid- ance to a practically unlimited number of aircraft; h) the grave responsibility of radio aids to air navigation for rendering reliable service to aircraft which, under certain circum- stances, may be entirely dependent for their safety upon uninter- rupted reception of satisfactory navigational signal; and i) the short period of time that has been available for engineering study since the September 1937 Inter-American Technical Aviation Conference at Lima; 3. The Inter-American Radio Conference resolves: a) That in accordance with the recommendations of the Lima Convention the countries participating in this conference should prepare and exchange not later than June 1, 1938 all pertinent data which may be of value in the drafting of the following tables which may serve as a guide in connection with the application of the engineer- ing principles herein set forth. Table I listing various types of radio aids to air navigation which have been approved for service operation; Table II establishing minimum signal intensities required for satisfactory reception of the various types of radio aids to air naviga- tion, such data to be used as a basis for determination of normal service areas; Table III establishing permissible values of interfering signal strength for the various types of radio aids to air navigation expressed in ratios of desired to undesired signal at the minimum service signal contour (a) on the same frequency, (b) 3 kc/s removed in frequency, and (c) 6 kc/s removed in frequency. b) that radio aids to air navigation, especially those which are of a one-way or broadcast nature, such as radiobeacons, should be expected to maintain the highest possible standards of reliability, stability, and quality of emissions: c) that in the interests of economy of frequencies the limited num- ber of channels suitable for the use of radio air navigational aids should be assigned with the closest practicable separation, considering the type of service and class of emission, and that, as far as possible, all nations should reserve the same bands for similar types of service in order to simplify receiver design and through standardization extend the geographical limits of usefulness. d) that the sharing of frequencies to provide facilities within the authorized bands might be arranged by regional agreement between the countries within whose borders lie portions of the interference area of existing stations as determined by the table of interference ratios and service signals;
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