Thanks for the info. I don't think that siren is active anymore, since Bellevue and Dayton merged their fire departments years ago.
Also, I found 3 more MOD4016s in Campbell County while playing around with the new Google Maps Engine Light (Google now has 45-degree-angle satellite view in many areas

):
Highland Hills Park, Mayfield Avenue, Fort Thomas
Tower Park Hall, Caramel Manor Drive, Fort Thomas (in the parking lot here - should be visible from River Road as well)
NKU softball field, Softball Road north of Johns Hill Road, Highland Heights
I know there are several others around the NKU campus, but I don't know how many of those are part of the county system. The one by the softball field fills in a nice hole in coverage so that one probably is.
Edits:
I sent an email to the Campbell County Office of Emergency Management asking about that siren in Bellevue. It's possible it might still be active...
Also, for those who are interested, here's an updated map of Campbell County sirens:
https://mapsengine.google.com/map/edit? ... YXn7xUmRjw