History, present status, and future directions of HF surface-wave radars in the U.S

HF surface-wave radars (HFSWRs) offer two distinct advantages when used over the sea: with vertical polarization, they see beyond the horizon, and the interaction of their signals with ocean waves is simple and well understood. As a result, many HFSWR research test programs were conducted in the U.S., beginning 35 years ago. This author was fortunate to have been immersed in these programs from the beginning. Early projects by the Defense Department focused on military target surveillance: ships, aircraft, and missiles. In the mid-70s, their potential was explored for environmental measurements: surface currents and sea state. Why after 35 years of testing and evaluation are none found in operational service today, except those made by CODAR for environmental monitoring? I discuss this question in the present paper.