Abstract
IN the radio range-beacon system now used on American airways, it is sometimes very difficult to determine the absolute direction of the aeroplane when it is near the radio beacon. The pilot can easily pass from one quadrant to another without knowing it. When once so lost, he may wander many miles from the beacon before he can find out which quadrant he is on. Tests show that the average pilot, when flying under the hood and purposely lost, requires about an hour to find his course. In the Journal of Research of the Bureau of Standards for September, Mr. F. W. Dunmore describes aural, visual and combined methods which enable the pilot to identify the quadrant with certainty. In the aural method, directive signals are sent out; a one dot signal in a westerly direction, two dots easterly, three dots north and four dots south. Depending on which set of these signals is the loudest, a pilot can determine his general direction from the beacon. During an interval between the sending of the beacon station identification letter, the one dot and two dot signals are sent out, and during the next interval the three dot and four dot signals are transmitted; which two of the four sets of signals are heard loudest enable the pilot to determine his course. In the visual system, use is made of an indicator the reeds of which are affected by the signals, and their relative amplitudes enable the course to be determined. An advantage of the system for course and quadrant identification is that it can be readily applied to existing beacon stations as it requires no alterations to the antenna structure. Photographs of the devices and full diagrams of the necessary circuit arrangements are given.
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Guiding Aeroplanes when about to Land. Nature 132, 925 (1933). https://doi.org/10.1038/132925b0
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DOI: https://doi.org/10.1038/132925b0