Part of the secret shame of being a two way radio guy (and infrastructure in general) is the constant opportunity to view new and exciting antennas just out on the street. Once viewed, I can anguish and obsess over identification of the details to later point out to uninterested companions :smack:
I pass this tower on my commute. It is directly in front of a United Airlines facility which is itself on O’Hare Airport grounds (or at least the border). The tower is on Touhy Avenue at Interstate 90 (The Jane Addams) near Rosemont and Des Plaines, Illinois.
Wide shot (under the yellow sign) shows scale WRT to the surrounding area. It’s literally right up to the airport and cannot be too tall.
Some detail. Not a bad shot for zoomed in and at 65mph.
Right now, I have to think its just an observation deck. The top is pretty large, maybe 18’x18’. There’s no apparent antennas or comm gear. There is a structure at the base but there’s no outward signs of the contents. The airport is in the early stages of a major expansion and maybe they wanted to get a high vantage point during construction…?
I have no guesses for the tower, but please tell me that you were merely a passenger in the car taking these shots and not driving/taking pictures at the same time.
I’d assumed those were for lightning protection and to mount flashing red airport proximity lights. Why build a massive tower with staircase and top floor parking for 4 spindly antennas?
I cannot, I’m afraid. Shame on me. I guess I let my guard down on familiar drives.
Looks like antennas on the corners for sure, may also be something else in the center there. One wonders if the antennas have to be separated the 20’+ for some reason, perhaps for directional purposes. Also, for a simple antenna tower there is a pretty secure – and expensive – stairway to a platform, with railing, on the top. Must be some reason for humans to go up there on a routine basis. Maybe a weather station of some sort?
I noticed it back in December or January, I’m pretty sure. No idea if it had been up for 10 years and I just didn’t notice it before that, though. But it did make me go, “Bwhuh?” as I drove past.
My husband (fir fighter for a large aircraft manufacturer) says its a radar tower, either newly built, waiting for its complement of equipment, or one that’s been decomissioned.
Looks like a phased array to me. A bit out of my depth, but I gather that you can vary the phase of the signals going to each antenna to direct the strongest lobe of radiation in any direction. Likewise, you can compare the phases of received signals to find the direction of a transmitter, reflected signal, or (most likely, given the location) aircraft transponder.
I think it could very well be used for radar just as it is, no dish needed. I’m not sure how accurate you could make this particular rig, but I know the military gave up radar dishes for phased arrays long ago, in some applications.
Or it could be some sort of radio marker tower with redundant antennas, spaced apart to keep them from interfering with each other.
