Bell Telephone - Microwave Relays
July 1959 Electronics World

July 1959 Electronics World Table of Contents  Wax nostalgic about and learn from the history of early electronics. See articles from Electronics World, published May 1959 - December 1971. All copyrights hereby acknowledged.

Bell Telephone Laboratories was largely responsible for designing and building a communications system that was the envy of the world. Innovation on the part of Bell engineers, manufacturing staff that produced the equipment, and technicians who serviced the systems deserve the credit as do management types who made funds and opportunity available to the aforementioned. As the number of telephone service subscribers grew and reliability became even more vital to business, law enforcement, and national defense, new methods had to be devised. In the late 1950s, Bell introduced the concept of wireless microwave links at 11 GHz (X band), which at the time X band was primarily used (at 10 GHz) by precision approach aircraft radar. This advertisement in a 1959 issue of Electronics World magazine promoted Bell's achievement.

Bell Telephone Ad

"Packaging" Microwaves for Higher Mountaintops

In Arizona, the telephone company faced a problem. How could it supply more telephone service between Phoenix and Flagstaff - through 135 miles of difficult mountain territory?

Radio offered the economical answer: a new microwave radio-relay system recently created at Bell Telephone Laboratories. Operating at 11,000 megacycles, it was just right for the distance, and the number of conversations that had to be carried.

But first other problems had to be solved: How to house the complex electronic equipment; how to assemble and test it at hard-to-reach relay stations way up in the mountains; and how to do it economically.

On-the-spot telephone company engineers had some ideas. They worked them out with engineers at the American Telephone and Telegraph Company and at Bell Telephone Laboratories. The result: A packaged unit.

The electronic equipment was assembled in trailer-like containers at convenient locations and thoroughly checked out. The complete units were then trucked up the mountains and lifted into position.

The system, now operating, keeps a watch on itself. When equipment falters, a relay station switches in stand­by equipment, then calls for help over its own beam.

The new Phoenix-Flagstaff link illustrates again how Bell System engineers work together to improve telephone service. Back of their efforts is the constant development of new communications systems at Bell Telephone Laboratories.

"TJ" radio-relay station at Black mesa, Arizona

Bell Telephone Laboratories World center of communications research and development

Posted August 28, 2023
(updated from original post on 6/20/2018)