Abstract: A high frequency, high speed data communication system for providing electronic mail, file transferring, Internet access, weather forecasts and other database and communication options to remote HF/MF users, such as vessels at sea. A conventional, multi-featured, land-line bulletin board system is employed at a central communication facility for the provision of data communication services. A remote computer accesses an HF/MF link at the central communication facility via an HF/MF modem coupled to an HF/MF radio and antenna. The HF/MF link includes an antenna, HF/MF radio, HF/MF modem, and an interface computer for performing protocol and interface conversion between the land-line BBS and the HF/MF modem. Multi-user capability is provided through the simultaneous employment of multiple HF/MF links at the central communication facility. Multi-frequency operation of each HF/MF link is provided through the scanning of each HF/MF radio in conjunction with an antenna tuning system.