ARRL

Arkansas VHFer Claims “Mathematically Impossible” AO-7 Mode B Distance Record

02/17/2016

Dave Swanson, KG5CCI, of Arkansas has achieved another distance milestone on the venerable AO-7 satellite using Mode B (70 centimeters up/2 meters down).

On February 10, Swanson, on Shinnal Mountain west of Little Rock (EM34st), completed a scheduled contact with Eduardo Erlemann, PY2RN (GG66lw), a calculated distance of 8030.895 kilometers (approximately 4979.2 miles), which Swanson said was “way beyond the theoretical range AO-7” and a feat that “the math said shouldn’t be possible.”

The tricky part was that, given their respective locations in the Northern and Southern hemispheres, the window allowing both to access the satellite at the same time was on the order of 5 seconds. After several attempts, they agreed to use quick call sign/grid square reports.

“At 2009 UTC, both stations clearly heard the other’s call and grid, completing the contact,” Swanson said. “It was extremely rapid and very weak, but clear…I think this is approaching the limits of what can be done on AO-7.” PY2RN has posted his side of the contact, which Swanson called “by far the hardest sked I’ve ever attempted.”



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