The Coast Guard announced Monday a change to the marine radio frequency that mariners must use to activate fog signals on navigable waterways of the Great Lakes.
Until the change takes effect on July 1, mariners are advised to use both the new and the old frequency.
Since the 1990s, mariners encountering decreased visibility have been able to activate fog signals on certain aids to navigation by tuning their marine radios to VHF-FM channel 79A (156.975 MHz) and keying their microphone five times.
The channel used for this purpose is being changed to channel 83A (157.175 MHz).
This change is being made to shift radio traffic from channel 79A, a commercial channel, to channel 83A, a frequency owned and operated by the Coast Guard.