Hams in Germany and Portugal reportedly have received signals from the US Voyager 1 spacecraft http://voyager.jpl.nasa.gov/ in March and April. On March 31, AMSAT-DL (Germany) radio amateurs at the Institute for Environmental and Future Research (IUZ) at Bochum Observatory used a 20-meter radio telescope dish to detect Voyager 1’s 8.4 GHz signal.
Using Doppler shift and sky positioning, the German team received the signal from a distance of 8.82 billion miles (14.7 billion km)–nearly 100 times the distance from the sun to Earth. This is the first recorded reception of signals from Voyager 1 by radio amateurs.
Members of the AMSAT-DL/IUZ team included Freddy de Guchteneire, ON6UG, James Miller, G3RUH, Hartmut Paesler, DL1YDD, and Achim Vollhardt, DH2VA/HB9DUN. Assisting were Theo Elsner, DJ5YM of IUZ, and Roger Ludwig of Jet Propulsion Laboratory (JPL), as well as the Deep Space Network (DSN) tracking station in Madrid, Spain.
Luis Cupido, CT1DMK, in Portugal reported April 15 that he spent “two nights without sleep” to hear Voyager I at his QTH using a 5.6-meter dish. To detect the signal, Cupido says he had to acquire and integrate spectrograms over an extended period.
“I did several acquisition periods of 15 minutes (900 s), the minimum I would expect to see something,” he said on his Web site http://w3ref.cfn.ist.utl.pt/cupido/dsn.htm noting that any longer time period would be incompatible with his Doppler-shift correction scheme. “The receiver is operated at fixed frequency, and the Doppler variation was corrected by skewing successive spectrograms in software while accumulating [images].”
He based positive identification of Voyager 1’s signal on the fact that signal is “only visible for the right skew amount that corresponds to the Doppler variation as predicted by the relative velocity calculation.”
Voyager 1 was launched in September 1977 to conduct close-up studies of Jupiter and Saturn, Saturn’s rings and the larger moons of the two planets. Designed to last only five years, the probe is expected to send back astronomical information to NASA and JPL until at least 2020. Voyager 1 will study ultraviolet sources among the stars, and its fields and particles instruments will continue to search for the boundary between the sun’s influence and interstellar space.