Oscar Cabatic, 36th Maintenance Squadron Precision Measurement Equipment Laboratory technician, analyzes a signal using a transponder test set, a spectrum analyzer, and a peak power meter June 19, 2015, at Andersen Air Force Base, Guam. PMEL technicians ensure all the equipment they calibrate on a daily basis is accurate and reliable for the many units they support. (U.S. Air Force photo by Airman 1st Class Arielle Vasquez/Released)