U.S. Air Force Tech. Sgt. Larry Knoll programs radio frequencies to a PRC-117 in Houston, Texas, Sept. 13, 2008. Knoll is assigned to 14th Air Support Operations Squadron on Pope Air Force Base, N.C. U.S. Air Force Tech. Sgt. Larry Knoll programs radio frequencies to a PRC-117 in Houston, Texas, Sept. 13, 2008. Knoll is assigned to 14th Air Support Operations Squadron on Pope Air Force Base, N.C. SHARE: Download: Full Size (1.5 MB) Tags: photo essays Credit: VIRIN: 330246-E-WER41-966.jpg Photo Gallery