Epperson TV Coverage Calculator

According to the instructions received with the object, as long as one knows a TV station's published power and antenna height, this slide rule "quickly shows the approximate 'Grade A,' 'Grade B' and 'Principal City' Coverage for all VHF and UHF Television Stations. In addition, it readily gives the approximate field strength in microvolts-per-meter for distances up to 100 miles from the television transmitter."

This one-sided wooden instrument is painted white on the front. A plastic indicator is in a metal frame. The top of the base is marked: EPPERSON TV COVERAGE CALCULATOR. It is also marked: COPYRIGHT 1952 (/) J. B. EPPERSON. The bottom right corner of the base is marked: ADLER COMMUNICATIONS LABORATORIES (/) NEW ROCHELLE, N.Y. The back of the rule has charts for converting decibels above one microvolt-per-meter to microvolts-per-meter and for identifying FCC required field intensities. Values from these charts are used in making calculations on the front of the rule.

Adler built numerous television and radio stations, including the first commercial UHF station, located in Portland, Ore. Founded by Benjamin Adler in 1947, the company changed names to Adler Electronics, Inc., in 1955 and remained in business at least through 1964. It probably distributed this rule as a promotional item. The rule was manufactured by Engineering Instruments of Peru, Ind., the successor firm to Lawrence Engineering Service. Compare to 1983.0042.01 and 1980.0097.02.

Joseph Bolen Epperson (1910–1995), the designer of this rule, studied at the University of Tennessee from 1927 to 1929 and with the Capitol Radio Engineering Institute (now Capitol College in Washington, D.C.) in 1932. After gaining experience as a chief engineer and supervisor of building and transmitter installation at radio stations in Knoxville, Tenn., and Huntsville, Ala., he joined Scripps-Howard Radio, Inc., of Cleveland, in 1937. He remained with the company until his retirement in the 1970s, leading the construction of several television stations and rising to vice-president for engineering in 1956. Pioneer and Headley-Reed also distributed his rule, sometimes called a "signal range calculator."

References: Rene Brugnoni and Ben Adler, "Television—What and How," Broadcast News 72 (January-February 1953): 12–25; Adler Communications Laboratories, "Wherever Superior Engineering and Performance Are Demanded," Broadcasting, 1952 Yearbook, 425, http://www.americanradiohistory.com/Archive-BC-YB-IDX/50s-OCR-YB/1952-YB/1952-BC-YB-for-OCR-Page-0423.pdf; Joan Cook, "Benjamin Adler, 86, An Early Advocate of UHF Television," New York Times, April 18, 1990; David G. Rance, "The Unique Lawrence," Proceedings of the 17th International Meeting of Slide Rule Collectors (September 2011), 97, http://www.sliderules.nl/index.php?p=papers; "Joseph Bolen Epperson," Who's Who in Engineering (New York and West Palm Beach: Lewis Historical Publishing Company, Inc., 1964), 537–538; The Billboard (December 27, 1947), 15.

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