A portable tester verifies the operational status of a satellite-based navigation ground facility. Also disclosed are polymer composite baseball bats where the polymer composite material includes between 85% and 100% fiberglass reinforcement fibers, andor where the central cavity is filled with a damping material such as polymeric foam or a low-density granular material, andor where the bats are constructed of multiple layers of intertwined tubular braid forms using a precision molding process. The speed of the peripheral device may be adjusted in response to one or more predetermined conditions.