Lithuania Army Junior Sergeant Andrejus Alimovas, High Frequency (HF) SENIOR Operator adjusts the frequency on an HF mobile radio prior to a test during Exercise COMBINED ENDEAVOR 2000. The Exercise is a Partnership for Peace (PfP) exercise hosted by Germany and is the largest information and communications systems exercise in the world which focuses primarily on Command, Control, Communications, and Computers (C4) interoperability testing and documentation