DAVIDSONVILLE, Md. – Senior Airman Justin Cahill, 89th Communications Squadron Davidsonville Communications Site radio frequency transmission systems technician, left, and Staff Sgt. Ian Bobnes, 89 CS frequency transmission systems craftsman, right, test the high frequency global communications system antenna matrix motor actuator voltage with a multimeter and technical order instruction Jan. 12. The purpose of the test is to check the functionality of the actuator motor. (U.S. Air Force photo/Bobby Jones)