An 80-watt failure in 1940<\/h2>\n\n\n\n
DeWitt first tried on the night of May 20, 1940, with equipment from WSM, the Nashville radio station where he was chief engineer. His 80-watt transmitter sent 138-MHz waves toward the Moon, but the receiver was not sensitive enough to catch a return.<\/p>\n\n\n\n
“It occurred to me that it might be possible to reflect ultrashort waves from the moon,” he wrote in his notebook. By 1945 the Army had a reason of its own, since the Chief Signal Officer wanted radars that could detect Soviet missiles. No missiles were available for tests, so the Moon stood in for them.<\/p>\n\n\n\n
The open question was the ionosphere, the layer of charged particles that bends and reflects radio waves. According to the IEEE milestone record<\/a>, the project settled doubts about whether long-range radar signals could pass through it.<\/p>\n\n\n\n In September 1945, DeWitt assembled Harold Webb, Herbert Kauffman, King Stodola and Jack Mofenson. Walter McAfee, of the laboratory’s theoretical group, calculated how much signal the lunar surface would reflect.<\/p>\n\n\n\n The team designed no major components for the job. It used equipment already on hand, including a crystal-controlled transmitter and receiver designed by radio pioneer Edwin Armstrong.<\/p>\n\n\n\n Wartime radars sent bursts lasting a few millionths of a second. That suited aircraft, not a target about 238,000 miles (383,000 kilometers) away. DeWitt’s group stretched the pulse to about a quarter of a second and worked at 111 MHz.<\/p>\n\n\n\n Two “bedspring” antennas from SCR-271 radars went side by side on a 100-foot (30-meter) tower. The mount could turn only from side to side, so the crew could try only when the Moon was rising or setting.<\/p>\n\n\n\n Motion shifted the returning signal by as much as 300 Hz, the same Doppler effect that changes the pitch of a passing siren. Operators had to retune the narrow receiver each time. The first tests, in December 1945, brought burned-out vacuum tubes and failed circuits.<\/p>\n\n\n\n The crew saw the echo on a nine-inch cathode-ray tube and heard it as a 180-Hz beep. The trace showed clear deflections at about 238,000 miles, which matched the distance to the Moon<\/a>.<\/p>\n\n\n That run ended at 12:09 p.m., when the Moon moved out of the radar’s range. The Signal Corps repeated the experiment on each of the next three days and on eight more days that month.<\/p>\n\n\n\n General Van Deusen, who ran Signal Corps research in Washington, feared embarrassment and wanted outsiders to confirm the story first. George Valley and Donald Fink of the Radiation Laboratory came to watch a moonrise test run by Stodola. Nothing appeared.<\/p>\n\n\n\n “Shortly, a big truck passed by on the road next to the equipment and immediately the echoes popped up,” DeWitt wrote in a 1977 letter. He suspected a crystal that had not been oscillating or a loose connection that fixed itself.<\/p>\n\n\n\n “Everyone cheered except the General who tried to look pleased,” he added. The War Department announced the result on the night of January 24, two weeks after the first echo.<\/p>\n\n\n\n On July 24, 1954, the Navy reflected voice off the Moon from Stump Neck, Maryland, to Washington. Satellites made that system obsolete in the later 1960s.<\/p>\n\n\n\n Radar astronomy grew from the same experiment, because scientists could now send a signal at a planet and read what returned. One recent case is the radar search beneath the south pole of Mars<\/a>. The IEEE’s 2019 plaque says Project Diana “marked the beginning of radar astronomy and space communications.”<\/p>\n\n\n The InfoAge Space Exploration Center<\/a> at the New Jersey site still has a TLM-18 dish that once tracked TIROS weather satellites. The center says the dish still completes Earth-Moon-Earth transmissions at about 1,296 MHz when the Moon is available.<\/p>\n\n\n\n NASA’s Goldstone radar applies the same principle to asteroids passing near Earth<\/a>. On July 28, 2025, it imaged asteroid 2025 OW<\/a> about 400,000 miles (640,000 kilometers) away, resolving features 12 feet (3.75 meters) wide.<\/p>\n\n\n\n NASA’s history puts moonrise at 11:48 a.m., ten minutes before the first echo, while the IEEE’s history site gives 11:58 for moonrise itself. The IEEE plaque names an SCR-270\/1 radar, and NASA and the Army describe SCR-271 hardware.<\/p>\n\n\n\n DeWitt himself supplied the lunch and the truck more than 30 years later, so both rest on memory. The claim to be first is firmer. The IEEE found no earlier documented success, and Zoltan Bay, whose Hungarian team detected lunar echoes on February 6, 1946, acknowledged the American result.<\/p>\n\n\n\n The fullest official record appears in NASA’s 1996 history by Andrew Butrica, published as SP-4218.<\/p>\n\n\n\n Photo: U.S. Army CECOM<\/p>\n","protected":false},"excerpt":{"rendered":" A US Army Signal Corps team bounced radar off the Moon on January 10, 1946, from a laboratory near Belmar, … <\/p>\nBedsprings and a quarter-second pulse<\/h2>\n\n\n\n
Eleven minutes on a nine-inch screen<\/h2>\n\n\n\n
![\"Oscilloscope](\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/11\/osciloscopio-eco-luna.jpg\")
The truck that rescued the demonstration<\/h2>\n\n\n\n
From moonbounce to asteroid 2025 OW<\/h2>\n\n\n\n
![\"Aerial](\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/11\/sitio-diana-camp-evans.jpg\")
Archives disagree on that morning<\/h2>\n\n\n\n