Real-time adaptive HF frequency management

In 1972 the United States Air Force began a program aimed at improving tactical HF communications. The approach involved measurement in real time of the important unknowns: propagation, noise, and spectrum occupancy, and adapting operating frequencies in real-time to the conditions measured. A potential problem with this approach is causing harmful interference to other spectrum users. An exercise called TROPHY DASH III was conducted to assess the ability of a particular technique to permit real-time selection of frequencies while yielding acceptably low interference. TROPHY DASH III results are viewed as significant. First, in spite of extensive notification of other spectrum users, negligible interference was reported. Based upon these results, real-time adaptive sharing of the HF spectrum in the tactical theater appeared both valid and feasible for a limited number of high-priority users, and procurement of the AN/TRQ-35(V) Tactical Frequency Management System was authorized.