The military has turned to a directed energy frequency jammer mounted on an assault rifle-type frame to deal with the growing threat of small drones to military bases and troops in the field.Officials of Battelle, the non-profit research and development organization based in Columbus, Ohio, said Monday the Defense Department and the Department of Homeland Security had signed off on buying 100 of its “DroneDefender,” billed as the “safe” solution to warding off intruding unmanned aerial vehicles. Battelle officials at the Navy League’s 2016 Sea-Air-Space Exposition at National Harbor in Maryland outside Washington, D.C., said they could not discuss the unit cost or the total cost of the sales to the departments.“It’s a portable solution to stop portable drones,” said Rich Granger, a Battelle business development director for Mission and Defense Technologies. The DroneDefender has two triggers — a “command and control” trigger to sever the link between the pilot and the UAV, and a second trigger to jam GPS links to the drone. The device can intercept drones out to 400 meters. Once the drones are disabled, they are programmed to hover safely to the ground, said Kim Stambler, a Batelle business development and sales leader.Stambler said the Pentagon bought the DroneDefender for use in the U.S. and overseas.