I have a Coast guard station nearby that often has their system "lock up" VHF Marine Channel 16 for the local area. They are using Raytheon ACU1000 units, and my Standard Operating Procedure as Frequency and Spectrum Manager years ago, was to reboot these each shift to prevent this from happening. That was a decade ago, and yet, I still notice it taking place, even now....and probably several radio administrators later.
With Automatic Link Establishment (ALE) and computer control, many legacy frequencies seems to be in use across the country, with no real check of usable quality. On the other hand WSPR (Weak signal Radio Propagation) is also used by many to predict the prorogation quality of an HF signal too.
As for the Coast Guard itself and their radio use, they always have their budgets cut, even though they have a "real and viable" mission that benefits many more than people tend to know. (I am retired Air Force, but worked with the Coast Guard while I worked in the oil industry for a decade). The Coast Guard often gets old gear, a lot less budget, and ships held together by paint, and told to go do something like maintain buoy markers or manage the clean up of an oil spill.
