JimThePCGuyFormerly known as schja01.Premium,MVM
Morton Grove, IL
I wanted to see if there was any indication on the enclosures at the base of the towers but I'd have to climb a fence or trespass on railroad property to get close enough. Plus even being in a decent northern Chicago suburb the area these are located in is not the best. I wouldn't be surprised if there wasn't a meth-lab nearby.
I felt a little strange even snapping these photos in light of 911 and thought doing one of the above would cause justified suspicion.
Plus being at retirement age I'm not into climbing barb wire fences any more.
PS. My guess was the middle one since it was the simplest. If Clear does use microwave for their back-haul then the leftmost would be the likely candidate as you said.
Using the Clear coverage tool I scoped out other tower locations in my area and looking at the aerial photos of stand alone towers (not water towers, not buildings and not multiple towers) every one looks a lot like the one on the left as you said because of the microwave dish antennas.