Lunar Radio Echoes

Abstract

High-power radars at the Naval Research Laboratory have been used to study the reflecting properties of the earth's moon. Experimental work over the last six years at frequencies in the 30-mc to 3000-mc band has revealed a lunar surface phenomenon which produces a "highlight." Measurements made at 198 mc have shown that more than 50 per cent of the echo energy is reflected in the first 50 microseconds after the leading edge of a short incident pulse contacts the moon. This fortunate situation permits many interesting astronomical observations and suggests the use of wideband communication signals in a circuit using the moon as a passive relay. Many types of modulation have been successfully passed over the lunar circuit, including amplitude modulation by voice.