Live Radar Audio Feed--how do we do it? It's simple. The Air Force Space Surveillance Radar transmits a 216.98 MHz signal into the heavens 24 hours a day, 7 days a week. Meteors, satellites and spacecraft passing overhead reflect those signals back down to Earth. The radar's primary antenna is located near Lake Kickapoo, Texas. A few hundred miles away in Roswell, New Mexico, radio engineer and long-time spaceweather.com associate Stan Nelson picks up the echos using a yagi antenna on his roof: photo.

Stan offers these details: "I'm currently tuned to 216.97927 MHz. using (USB) Upper Side Band on a ICOM R8500 receiver. The antenna is a 13 element yagi pointing east with a 15 degrees upward tilt. The receiver audio is sent to a ACER PC (Vista Windows) line input. The audio is encoded running Edcast using AAC at 16Kb. I have a 20 db. pre-amp at the antenna feeding about 50 ft of RG8." [photo]

Other ham radio operators in the southern USA may wish to try picking up the signals themselves. Sample reflections and observing tips may be found at these web sites:

Ghosts of Fireballs Past (Science@NASA)

Listening to Satellites on a Shoestring Budget (Tom Kneisel)

More about the radar: Formerly known as NAVSPASUR, the Air Force Space Surveillance Radar transmits 800 kW of continuous-wave (CW) radio power into an east-west oriented fan beam at 216.98 MHz. The radar's primary mission is to track satellites and space debris for the US Space Command. It can detect objects as small as 10 cm orbiting 15,000 km above the earth's surface.