Statistics on bridge-to-bridge frequency usage at selected sites in the Eighth Coast Guard District

Equipment was assembled and tested to record the time of occurrence and the duration of transmissions on the vessel bridge-to-bridge radio frequency, VHF-FM Channel 13. The input to this equipment was provided by magnetic tape recordings previously obtained at each site over a 24 hour period or by directly connecting the equipment to a VHF-FM monitor receiver. Message length histograms indicated that about 50 percent of all transmissions were of less than 3 seconds in duration and that about 95 percent of all transmissions were of less than 10 seconds in duration. The sites for which data was obtained include Port Allen, New Orleans, Harvey Locks, Venice, Houma, Berwick, Berwick Locks, and Intercoastal City, LA, and Galveston, Port Arthur and Orange, TX.