Introduction by George Kupczak of the AT&T Archives and History Center
Seven Hilltops was an interstitial in the film Rehearsal: The Bell Telephone Hour, which was released to theaters in 1947. The animated interstitial film traces communications via hilltop-to-hilltop from its earliest origins — Native American smoke signals and 1800s mirror signaling.
In 1947, microwave radio relays had just been developed (during WWII), and were being rolled out across the United States. Dependent on terrain, this method of radio-relaying telephone conversations and television signals was only useful in certain geographic areas, and within a certain range. In 1951, the first television signal made its way across the United States using a combination of microwave radio relay and coaxial cable.
By the time more powerful microwave transmitting towers were designed — 1980s — the microwave television/telephone signals were beamed from city to city across the United States, rather than just hilltop-to-hilltop, with a few exceptions. Most cities throughout the East and Midwest had microwave relay arrays at the top of the tallest building in the city, usually concealed by the building's architecture, but occasionally on display. And even though microwave relays are rarely in use today, their distinctive shovel-shaped antennae can still be seen.
Footage courtesy of AT&T Archives and History Center, Warren, NJ