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.

18:09 video

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.

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Terry Lee posted three photos with the comment: "I've been looking at this 1950's AT&T Long Lines Microwave tower my entire life!  This is one of 49 concrete towers AT&T built and this one is located in NW Ohio.  Research shows the radio room at the top level, next down is a 130/250v battery room, third level down is a 12v filament battery room and a generator room is at ground level."

[There are many comments providing photos and locations of other towers. And some comments provided some interesting links:

long-lines

some internal photos

a book

Valparaiso Tower (I need to check out this one.)

]

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Robin Griffin commented on Terry's post
Before fiber I worked for AT&T Long Lines in "non located construction" on an iron gang. We modified these towers, changing out antennae, upgrading the structure, running "wave guide", patching antennas when they got shot and rebuilding them when they got hit by tornadoes. Yours truly chilling on the back of a "KS horn" somewhere in Missouri in the winter.

Hansika Mittal posted
Growing up in Northern Indiana, I remember seeing these every 32 miles or so and never knowing what they were. These are microwave towers that were part of AT&T's Long Lines network. Towers like this were built to withstand a nuclear war to ensure communications across the country. They could be manned and often had an adjoining bunker. With the end of the Cold War and other means of communication, many of these towers were abandoned or repurposed for other uses.

Doug Barden: I worked for at&t in Evansville at before microwave was made obsolete by fiber. The fail safe facilities were underground L cable "coax" with underground buildings and shock mounted equipment.

Mark Thompson: The tall, poured concrete towers you see in northern Indiana, often with "horn" antennas, are remnants of AT&T's Long Lines microwave communication network, primarily built in the 1950s and 60s.

Key aspects of their history and purpose:

Long Lines Network: These towers were part of AT&T's nationwide network designed to transmit telephone and television signals long distances using microwaves. Microwave signals, unlike lower-frequency radio waves, travel in a straight line ("line-of-sight").

Need for towers: Because microwave signals don't follow the curvature of the Earth, AT&T had to build a network of relay towers roughly every 32 miles or so to send and receive the signals over long distances.

Nuclear Hardening: Many of these towers were built with reinforced concrete walls to withstand a nuclear war, ensuring critical communications could still function during a national emergency.

Early stations: Early towers, like the one near Valparaiso, were built of concrete to minimize signal loss, housing the electronics mid-way up the tower.

Decommissioning: The Long Lines program ended as fiber optic cables became the preferred method for long-distance communication in the late 20th century. A successor to AT&T sold many of these towers around the year 2000.

Current status: While many were abandoned or repurposed, some still stand and are used for various communication services, such as cell phone service or private microwave transmissions. The LaPorte tower, for example, is still operated for paging services and leased to other companies. The tower near Goshen is still used by AT&T for cell service and by AQ2AT, LLC for microwave transmissions.

Northern Indiana specific examples:

Angola: The tower near Angola was built in 1950 as part of the first transcontinental route from New York to Chicago. It measures 26 feet square and rises 210 feet.

LaPorte: The tower near LaPorte, also part of the original New York to Chicago route, was built in 1950 and rises 197 feet.

LaGrange: Another early tower, built in 1950, is near LaGrange and is 26 feet square.

Goshen: Built in 1950, the Goshen tower is 26 feet square and 133 feet tall.

Plymouth: This tower, built in 1967, is 188 feet tall.

Leo: Built in the 1950s or 60s, this tower rises 274 feet.

Anderson: Built in 1966, the Anderson tower is 345 feet tall and served as a hub, relaying signals to multiple locations.

These structures stand as a reminder of a bygone era in long-distance telecommunications history.

Dennis DeBruler commented on Mark's comment
These towers were not intended to be nuclear bomb resistant. As Doug Barden's comment explained, the nuclear resistant network was constructed with underground coax cables and underground switching stations. And that network bypassed major metro areas. The reason the towers for the first transmission route between New York and Chicago were built with concrete was that waveguides and the folded horn antenna had not yet been developed. The radio equipment was on the top floor right next to the antenna. I include an image of the initial antenna design, https://long-lines.net/tech-equip/radio/BSP402420100/9.html. They soon developed the waveguide and folded horn antenna so that they could use a steel tower with a building at the base. The steel towers made concrete towers obsolete in the 1950s.
[My comment is grey with no explanation.]

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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) (TedShideler)

Satellite

Ontario, IN

Update:

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Satellite

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.

Dennis DeBruler

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.

https://www.google.com/.../@41.6580826,-89.../data=!3m1!1e3

Casey Walters

Dennis DeBruler

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. (Satellite) 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.

Indiana?

I don't know the location, but it is worth saving because it still has some horn antennas.

Joe Boals posted
Growing up in Northern Indiana, I remember seeing these every 32 miles or so and never knowing what they were. These are microwave towers that were part of AT&T's Long Lines network. Towers like this were built to withstand a nuclear war to ensure communications across the country. They could be manned and often had an adjoining bunker. With the end of the Cold War and other means of communication, many of these towers were abandoned or repurposed for other uses.
[I disagreed that these were designed to withstand a nuclear attack. AT&T did have underground bunkers, but they were for switching equipment and they were deep underground. I'm sure the "hard network" stuck with buried coax cables instead of microwave towers.
Several comments indicate the locations of other concrete towers.]
Tom Bevins shared

Attica, NY

 

Sam Thornton posted, cropped
Odd question, but does anyone know what this is? Approximate location included.

Dennis DeBruler: Found it: https://maps.app.goo.gl/c2BBumJh8Rwov1V48

When Bell Labs developed microwave communication in the 1950s, they had yet to develop waveguides. So the first microwave towers were built to hold all of the electronics up in the air by the antennas. And we are talking vacuum-tube electronics. I know there are several of these towers along US-20 in northern Indiana because one of the first microwave routes built was between New York and Chicago. If you can still find a metal microwave tower, the electronic equipment is now in the little building at the base of the tower. In these more modern towers you will see rectangular tubes that go up the tower from the building to the antennas. Those are the waveguides that made building concrete towers obsolete.

Comments on Sam's post