WASHINGTON — Boeing Network & Tactical Systems of Huntington Beach, Calif., recently completed a series of demonstrations with a lightweight communications payload aboard an unmanned aerial vehicle (UAV) that could provide better connectivity to deployed forces, a company official said.

The U.S. Defense Department has bought hundreds of thousands of hand-held line-of-sight radios to keep troops connected on the battlefield. Mountainous regions such as Afghanistan are an impediment to these kinds of radios, and essential communications generally travel over expensive satellite links, which are in short supply these days.

Boeing developed a narrowband communications payload that can fly on widely deployed small UAVs such as the ScanEagle, Shadow and Raven without disrupting the primary surveillance mission of the aircraft, said Dick Paquette, Boeing’s program manager for command, control, communications, computers and intelligence programs.

For an internally funded demonstration Boeing conducted in June, the communications payload was attached to a Boeing-built ScanEagle UAV. The aircraft flew over Washington and Oregon at altitudes from 500 meters to 4,000 meters for a total of about 10 hours, Paquette said in a July 29 interview. Several hand-held radios were able to communicate with one another as they were driven in cars around the states’ hilly terrain, Paquette said.

Boeing also conducted a successful demonstration July 28 at Fort Huachuca, Ariz., in which the aircraft flew at altitudes as low as 150 meters through rain and lightning, he said.

Other companies have built communications payloads for UAVs, but they have generally been for use on larger UAVs such as the Predator, Paquette said. Thales Communications of Clarksburg, Md., and Harris Corp. of Melbourne, Fla., each offer payloads that weigh 2 to 3 kilograms and draw about 120 watts of power, he said. The Boeing payload weighs less than a kilogram and draws 14.7 watts of power, he said.

Boeing came up with the idea for its payload based on conversations with U.S. Space and Naval Warfare Systems Command, or Spawar, which expressed interest in a lightweight UAV relay that could connect troops anywhere within a 160-kilometer radius of the airborne craft. Paquette would not be specific but said the Boeing model exceeds Spawar’s distance requirement.

The Navy operates a narrowband satellite system called the UHF Follow On, but that constellation has become depleted over the years while its replacement system has been delayed, resulting in a capacity shortage.

In addition to San Diego-based Spawar, Boeing has discussed the possibility of conducting additional demonstrations with other potential customers including U.S. Special Operations Command and the Navy Expeditionary Combat Command, Paquette said.