Radio Amateurs Receive Rosetta Spacecraft Signals from Deep Space
James Miller, G3RUH, was among a small handful of Amateur Radio operators to receive the X band signal January 21 from the European Space Agency’s Rosetta spacecraft, some 500 million miles from Earth. Miller used the 20 meter dish at the Bochum Amateur Radio facility in Germany, run by AMSAT-DL and IUZ Bochum Observatory. In an AMSAT-BB post, Miller noted the frequency at the spacecraft was 8421.786900 MHz, and the signal was 14 dB below that of the STEREO A/B spacecraft. Perhaps more astonishing, Bertrand Pinel, F5PL, was able to track Rosetta 65 kilometers from Toulouse using his “home-rigged” 3.5 meter dish and receiver. Viljo Allik, ES5PC, a member of Estonian Student Satellite Program team reported his group was able to detect the satellite’s signal using a slightly smaller dish.
“We have recently established our own small ground station for mostly educational purposes to get more interested students into space technology,” Allik said in a reply to Pinel’s European Space Agency blog post. The Estonian group used a 3 meter dish. Allik said the signal-to-noise ratio was in the range of 3 to 5 dB in a 1 Hz bandwidth. “So it was really exciting to see the signal from such large distance with our very simple receiving station. The elevation of the Rosetta spacecraft at our location was only about 4° during the reception.”
The equipment used was “a kind of amateur design,” he said. “We detected signals from other spacecraft like Gaiaand STEREO A/B too, but the signal from Rosetta is the most-distant signal we have detected so far.”
Launched in 2004, Rosetta will both orbit and land on a comet, which it will reach this August, and send data back to Earth. The spacecraft consists of the Rosetta space probe and the Philae robotic lander.