Saturday, February 14, 2015

Concrete Microwave Towers

Reenforced concrete does make the study of Industrial Archeology easier. On one trip I was able to spot both of the concrete microwave towers that I remember from my childhood. So the concrete core of those towers are still standing. The trip was to Ohio using the Indiana Toll Road and returned using US-20 most of the way.

As explained in Long-Distance Phone Microwave Towers, when the first trans-continental microwave relay line was built in the late 1940s, waveguides had not been invented. The towers were big and made of concrete to hold all of the electronics at the top of the tower and they used the KS-5759 Delay Lens Antenna. I found a 1951 image of the 191 foot Chicago Heights tower that still had the Delay Lens Antenna. After waveguides and the KS-15676 Horn-Reflector Antenna was invented, the concrete towers were upgraded with this equipment. A 2009 image of the Goshen, IN tower still has these horns. The economic driver for installing this equipment was long distance calls and network TV. These towers helped distribute the TV signals for ABC, CBS, and NBC across the country. The New York - Chicago segment of the transcontinental service began service Sept. 1, 1950.

Angola, IN

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While driving west on US-20 as I approached Angola I could catch glimpses of a concrete tower south of town. So when I got to town, I went around the circle and headed south. I could not find a side road to take me further west to the tower, so I ended up finding a spot along the state road that did not have any trees in the foreground to grab a picture.

Thanks to the magic of digital zoom, I can get a better picture. The picture at the left is at the camera's resolution. After looking at the satellite image obtained from the Long-Lines site, I'm glad I didn't drive around anymore trying to get closer to the tower. This 191-foot tower is surrounded by trees so a clear shot of the tower is not possible.

La Porte, IN

I missed a turn off IN-39 to get to this tower.  So I went with plan B -- my wife taking pictures from the van as I drove west on the toll road. One of the shots came out relatively tree-free. It looks like maybe AT&T is letting the local ham radio club use this 162-foot tower. Glenn Peters has saved me the effort of trying again for the side road because he took several close up pictures in 2009. It looks like the ham radio club has added some more antennas since 2009. (see below)


Ontario, IN

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Bird's Eye View

Carol Stream, IL

Jason Jordan shared
Note the first generation concrete microwave tower and a much more modern (and higher) steel tower. Since this is 1978 and fiber optic cables were still being inveted, both towers have horn antennas.

At Facebook resolution
I new the first generation towers were used for the original link between Chicago and New York City. I wonder what link this tower was in. Note that it is on top of a local hill for maximum height above the horizon.

When I compared the picture to a satellite image, I could not believe how much the area has changed. Not only is all of this land now occupied by suburban sprawl, the curve in the track has been removed. I'm sure these towers are long gone.
Steve McCollum commented

Collins, IA

Steve's comments concerning some grain elevators:
I really like those slipformed concrete structures, both round and square elevators. I also like the square concrete former AT&T Long Lines microwave towers.
Like this one, at Collins, IA.
From long-lines, which has more info.
Steve McCollum commented "The first TD2 links were turned up for production 9/1/1950. The concrete towers were built in the late 40s. Follow this link for more. There are three separate articles."

Sublette, IL

Gus Rubio commented on a post
Sublette, IL, tower, just outside of Woodhaven Lakes, a private campground my family used to visit weekly many years ago. Always wondered what it was for back then.
Is this still standing? I looked for it on a satellite map. I did find a Tower Road. But the only tower I saw is a cell phone tower.
Good chance the cell tower is in the same spot the original tower was.

Plato and Tower Roads, Hampshire, IL

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My picture is towards the Northeast. This streetview is towards the Northwest. This Google Photo caught the tower with a blue sky and a little different angle.

South Chicagoland

3D Satellite

Several more photos are in the trip report.


  1. Great pictures Dennis! The LaPorte site is actually owned by a ham friend of mine! Another nearby site, Valparaiso, is owned by another friend of ours and I have been up inside of it and on top of it numerous times, including last month. They truly are wonderful pieces of history.

    73 Bill AD8BC

    1. Do you have any pictures of the inside? I would love to see those? Apparently, there were several floors and rooms where equipment was once held.

  2. The concrete & steel tower pair is the Cloverdale station - one hop west of Chicago-2. The steel tower was built to accommodate a North-South link. Cloverdale was also equipped as a cell-site for Bell Labs' late 1970s Chicago field trial of the Advanced Mobile Phone System (AMPS - the prototype for American cellphone).
    A total of 49 square concrete radio-relay towers were built: 28 on the NY - Chicago TD2 initial route, 12 between Chicago & Des Moines for transcontinental TD2, 4 between Syracuse & Albany, NY, 4 between Columbus & Cincinnati, Oh, and one on the route between Buffalo & Syracuse. That last single tower at Vernal, NY represents the transition from concrete to steel construction; the three other towers on this route were steel.
    The concrete towers initially had only four floors: a ground floor for electrical service and generator, one floor for tube filament battery, one floor for 130/250-volt plate battery, one floor for radio bays.
    The radio room was located as high as possible in the towers to keep waveguide echo paths as short as possible but no higher than about 100' so that the maintenance techs would not be too worn out to work on the radio gear. After Bell Labs developed the ferrite isolator as a means of suppressing waveguide echos it became possible to put the antennas on tall steel towers with a ground-level radio building - waw -

  3. There’s a few visible along the north side of the Ohio turnpike.

  4. I live on Long Island outside NYC around 60 miles from where the empire state bldg and we had the steel versions of the at&t towers all around since we just out into the Atlantic ocean away from the mainland 100s of miles on the nassau and Suffolk county line which is the highest point on Long island we had a huge steel tower even on a sunny day it had a grey shade to it like a foreboding dark tower and it had the biggest what I guess is the directional horns on it they were very large and were removed in the late 80s for smaller dishes and arrays but we used smaller towers in the communities heading away from the county line Suffolk and nassau are one of the most populated urban areas in the US and you cannot leave long island without going into NYC so everything was beamed south east in Patchogue the tower was right in town along the main drag and the one that was committed to 1950s civil defense and FAA TRACON at Islip airport that handles the NY air traffic corridor was hidden in a industrial park and had signs stating the tower was for Civil Defense and National Emergencys on the outside and it had the distinction of winning a national contest by the Department of Defense office of Civil Defense for Industrial Fallout Shelters since it was built in the early 60s and included a hardened Fallout Shelter to keep technicians onsite to keep the tower online post nuclear attack as Islip Center Coordinated communications for Air Defense of NYC and Long Island which was a huge military Aviation Mfg hub
    And included the people who detonated Nuclear Weapons across the pacific at Brookhaven National Lab
    Funny another winner of the fallout shelter design was a high school the same distance as the AT&T tower from the National Lab.the concrete towers have been becoming of great interest to me since they also were important channels of information during the cold war and I am going to find some of these towers that were abandoned and visit some sites next summer great article.

  5. I came here as a Plato Center resident wondering what this is about. :)

  6. There used to be a tall concrete microwave tower outside of Mutual, Ohio years ago. It was owned and operated by the USAF and it had a set of the horns at the top like most of these concrete towers. Sadly, in 1989 the USAF demolished the tower because they switched to modern technology. The method they used to demolish it was explosives and it fell in a big hole where they buried the tower after demolition. Today there is just a standard cell tower where it stood. Great pieces of history.