AT&T built thousands of microwave relay towers as part of its Long Line communications network. Although they haven’t been used as part of it in nearly forty years, many towers remain standing across Indiana. An early concrete example, the tower near Laporte rises 197 feet into the sky1.
The Long Line tower in LaPorte was built in 1950 as part of an inaugural route from New York to Chicago. Originally, it relayed signals from from Mishawaka, twenty-nine miles east, to another tower in Valparaiso sixteen miles southwest2.
After the Long Lines program ended, a successor to AT&T sold most of the towers around the year 2000. Today, a successor still operates LaPorte’s tower for paging services4. It leases the tower to other companies as well.
Sources Cited
1 Transmitter Characteristics (n.d.). Antennasearch. Web. Retrieved March 23, 2024.
2 Long Lines Map and Information (n.d.). Web. Map. Retrieved March 23, 2024.
3 Transmitter Characteristics (n.d.). Antennasearch. Web. Retrieved February 24, 2024.
4 (See footnote 4).
Is this the oldest one you have found?
One of them. From what I can find, all the concrete towers were built about the same time.