During the 1950s and 60s, AT&T erected numerous microwave relay towers throughout the United States. They were part of the Long Lines network, a transcontinental telecommunications system. Though these structures have long ceased serving their initial function, their imposing presence persists. One such tower stands tall in the rural landscape just south of Mt. Carmel, Indiana.
Originally, phone companies linked distant cities using costly cable connections. AT&T sought an efficient alternative and introduced an experimental microwave network called TDX in 1947. The company refined its prototype and unveiled an upgraded version, TD-2, in 1950. The technology ultimately served as the foundation of the Long Line network.
The 243-foot tower1 at Mt. Carmel was built in 19592. It relayed signals from Manchester, Indiana -twenty miles southwest- to another twenty-four miles northeast in New Hope, Ohio3.
The Long Lines program met its demise in the 1980s with the advent of geostationary satellites, enhanced fiber optics, and digital networks. Following the breakup of AT&T, a successor company sold the Mt. Carmel tower in 20034.
The structure retains its obsolete KS-15676 horn antennae, but it’s used as part of USA Mobility’s paging network today5.
Sources Cited
1 Transmitter Characteristics (n.d.). Antennasearch. Web. Retrieved November 20, 2023.
2 Franklin County Office of Information & GIS Services. (2023). Parcel ID: 24-11-23-100-002.000-019. Franklin County, Indiana Assessor. map, Brookville, IN.
3 Long Lines Map and Information (n.d.). Web. Map. Retrieved November 14, 2023.
4 (See footnote 2).
5 (See footnote 1).
