HAM RADIO SIGNALS FROM MARS: Ham radio operators are doing something that until recently only big Deep Space Networks could do. ”We’re monitoring spacecraft around Mars,” says Scott Tilley of Roberts Creek, British Columbia, who listened to China’s Tianwen-1 probe go into orbit on Feb. 10th. The signal, which Tilley picked up in his own backyard, was ”loud and audible.”
The signal Tilley received from Tianwen-1 is dominated by a strong X-bandcarrier wave with weaker side bands containing the spacecraft’s state vector (position and velocity). Finding this narrow spike of information among all the possible frequencies of deep space communication was no easy task.
”It was a treasure hunt,” Tilley says. ”Normally a mission like this would have its frequency published by the ITU (International Telecommunications Union). China did make a posting, but it was too vague for precise tuning. After Tianwen-1 was launched, observers scanned through 50MHz of spectrum and found the signal. Amateurs have tracked the mission ever since with great accuracy thanks to the decoded state vector from the probe itself.”
So far, Tilley has picked up signals from China’s Tianwen-1 spacecraft, NASA’s Mars Reconnaissance Orbiter, and the United Arab Emirates’ Hope probe–all orbiting Mars approximately 200 million kilometers away. How is such extreme DX’ing possible? Läs mer
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