A SURVEY OF LOW REFLECTION COEFFICIENTS FOR VARIOUS TYPES OF LAND AND FROZEN SEA FOR NORMAL INCIDENCE AT 1600 MC/S
CENTRAL RADIO BUREAU LONDON (UNITED KINGDOM)
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During development on radio terrain clearance indicators, work was done to measure the reflection coefficients from terrains expected to have the lowest values. The measurements were made at 1600 mc. They depended upon the reception in an aircraft flying over the terrain, of a signal transmitted vertically downwards from the aircraft and reflected back to it. The reflection coefficient of desert sand, 0.15 for an assumption of 0.85 for sea, was in agreement with a previously reported value at 400 mc and was considered to be the lowest reflection coefficient to be found from any natural terrain. Measurements over barren, frozen, arctic terrain or sea covered by several feet of ice produced reflection coefficients equal to those from desert sand. However, over terrain deeply frozen and covered by deep snow and vegetation, appreciably smaller reflection coefficients were measured.
- Flight Control and Instrumentation