John H. DeWitt, Jr.
John Hibbett (Jack) DeWitt Jr. ( born February 20, 1906 in Nashville, Tennessee, † January 25, 1999 ) was an American electrical engineer. He proved the permeability of the ionosphere for radio waves by he used the moon as a reflector. This principle use Earth - Moon-Earth radio links.
Life
DeWitt was the son of the judge at the Court of Appeals of the State of Tennessee John Hibbett DeWitt. Very early he started to be interested in electrical engineering and especially the wireless technology. At age 16, he founded the first commercial radio station Nashville, which he sent from his parents' living room.
He took on an engineering degree at Vanderbilt University in Nashville, left this in 1929 but initially not finish order at Bell Laboratories in Washington, DC to work. In 1932 he went back to Nashville to become chief engineer at the station WSM. In the same year he started with his brother Ward DeWitt to experiment with homemade telescopes.
After the beginning of World War II, he returned to Washington to work for the U.S. military at Bell Laboratories and the Evans Signal Laboratories on improvements of the radar. He held the rank of Lieutenant Colonel.
Shortly before the end of 1943 he was appointed director of the Evans Laboratories. Here he headed from 1945, the " Project Diana".
1946, after his retirement there, he worked for a year as an advisor to Clear Channel Broadcasting Service, who tried to get approved higher transmit power for their transmitters.
The following year he became president of WSM in his hometown of Nashville. There he met the astronomer Carl Keenan Seyfert know who taught at Vanderbilt University. DeWitt helped him out with his self-built 30 - cm reflecting telescope because the university had only a 15 -inch refracting telescope, which also stood in the middle of the city. He designed for Seyfert also photometer for photoelectric photometry. His telescope is now on the roof of Vanderbilt University.
In 1968 he left WSM and went into retirement.
He was a radio amateur with the callsign N4CBC. DeWitt was "Life Fellow" of the IEEE for his contributions to the field of broadcasting and showing of radar reflections from the Moon. For his contributions to the development of radar proximity fuze he was awarded the Order of the Legion of Merit.
He was married twice and had a son, a daughter and a stepdaughter. He died at home in Nashville.
Project Diana
During his time at the military research laboratory at Fort Monmouth Evans signal Laboratory, New Jersey, John DeWitt was appointed as Head explore whether radio waves can penetrate the ionosphere. This was militarily interesting to locate missiles that fly above it. DeWitt was planning the moon as passive reflector to use, so he named the project after Diana, the Roman goddess of the moon.
On January 10, 1946 at 11:58 clock, the research group had success, they heard the faint echo of its signal from the moon. For this, they used an antenna with 64 interconnected dipole antennas and a transmitter with an output power of about 4000 watts, the used frequency was 111.5 MHz.
By demonstrating that the ionosphere for radio waves can be penetrated, the foundation stone was laid for radar astronomy. Also was this realization for the incipient space of meaning, because it means the communication had proved with satellites and space vehicles as possible.