There's a broader area protected by a high fence with barbed wire. They had access there, cause the father is a radio engineer and have friends on various sites.
It's also in bordered by two farms, with a flood plain across the street, in a rural part of St. Charles County, in MO. Granted, home builders keep building subdivisions closer and closer, but just 10-15 years ago the closest residence was a mile or so away (outside the couple farm houses).
There's also danger/warning signage around the entire property, on all fences (including those around the towers).
Is that the KH0J transmitter? I've driven past that countless times and it seems so run-down I've often wondered if it was still transmitting. So many times I've wanted to park in the lot and take a gander... Probably for the better that I haven't!
Seeing the frequency on the sign with the FCC station ID brought back fond memories of the former licensee, KIRL. I listened to 1460 in the late 60's and early 70's when it played top 40 rock and roll. A nice alternative to the top 40 powerhouse at the time, KXOK 630.