Future high frequency radio (HFR) deployments proposed as part of the Pacific Islands Ocean Observing System (PacIOOS) ten-year build-out plan (2011-2021). HFR operates in coastal networks to map surface currents, observe waves, and detect vessels. Requires U.S. Federal Communications Commission (FCC) approval to transmit radio waves near the 5, 13, 25, and 48 MHz bands. The radio waves propagate over the horizon along the conductive ocean surface, limiting freshwater applications. Transmitted radio waves scattered by ocean waves and surface vessels are then observed by the HFR receivers. HFR operating in the lower frequency bands provide more range with less resolution while those operating in the higher frequency bands provide more resolution at shorter ranges.