According to a Spaceweather.com report, Scott Tilley, VE7TIL, in British Columbia, Canada, received a signal from the NASA Mars Reconnaissance Orbiter (MRO), flying just 274 kilometers (about 170 miles) above the red planet’s surface. The signal was an X-band carrier containing no data or telemetry.
“Its purpose is to allow for Doppler tracking,” Tilley explained. “The rapid change in pitch of the signal is caused by the relative motion of the satellite and the observer.” He used a homemade satellite dish to hear the orbiter.
Read more – via American Radio Relay League | Ham Radio Association and Resources http://www.arrl.org/news/view/british-columbia-radio-amateur-hears-mars-reconnaissance-orbiter