Surface-wave data acquisition and dissemination by VHF packet radio and computer networking

Abstract

Waverider buoy data are normally transmitted on a 27 MHz analog radio link to a shore station a few miles away, where the buoy data are plotted on a paper strip-chart recorder or logged digitally for later computer processing. Instead, we have constructed a relay station on Martha's Vineyard island that retransmits the received Waverider data over a digital, 148 MHz packet-radio link to a personal computer in our laboratory on Cape Cod, where the data are edited, processed, spectrally analyzed, and then sent over an Ethernet line to our Institution mainframe computer for archiving. Telephone modem access of a special wave-data file on the mainframe permits unattended data dissemination to the public. The report describes the entire system, including Waverider buoy mooring hardware, computer programs, and equipment. The purpose of the project was to learn what difficulties are involved in the automated acquisition and dissemination of telemetered oceanographic data, and to gain experience with packet radio techniques. Although secondary to these purposes, the long-term surface-wave monitoring off the southwest shore of Martha's Vineyard has its own scientific, engineering, and environmental benefits.