I have talked with the Shawnee County EM and he said something about Blue Valley Public Safety comming and taking the old sirens down, and putting new ones up. So i imagine thats where we get ours...but where does your town/county get theirs from? I do know Johnson County, KS Also gets theirs from Blue Valley
Here is Blue Valley's Website:
http://bluevalleypublicsafety.com/index.html