The army corp rangers will most likely use the county sheriff freq. At truman lake, they ate identified on Benton County sheriffs freq as "ranger xx" where xx is their radio number. For example, ranger 88 or ranger 27, etc. They also have their own vhf channels in the 163 mhz range but they are not repeated and therefore hard to hear unless you are close by. I cant remember the link but if i find it i will post it with the army corp frequencies they use. Hope this helps a little
Matt. N0ZOJ
former Deputy, Benton County Sheriff Department (Mo)