Applying the Radio Range to the Airways

In pursuance of the program of radio aids to flight undertaken by the Department of Commerce, experimental and installation work has progressed in the application of the radio range (directive radiobeacon) along the airways. To date, only the aural type has been put into routine daily operation, and it is the only type of beacon considered in this paper, which discusses methods of adjusting the space pattern of the beacon system in order that the courses may align with the fixed airways. These beacons also need to be readily distinguished from one another, and so designed that a minimum of interference is met. By using a vertical wire antenna in addition to the loop antennas and varying the relative power in the two loop antennas it was found possible to secure practically any array of courses desired. The radio ranges at Hadley Field, N. J., and Bellefonte, Pa., were employed in the experimental work with excellent results. The field-intensity measurements made gave space patterns which checked very well with the theoretical patterns for such antenna systems. Careful spacing of the radio ranges within the frequency band, as well as distinctive coding of each beacon, solved the problem of interference. In selecting the proper coding for the beacons a study of the physiological effects of various sound groups was made, and the final coding chosen was such as to give a signal of equal time duration on each side of the course.