El-Tronics SGM-18A GM Survey Meter (late 1940s)

El-Tronics SGM-18A GM Survey Meter (late 1940s)

This is a GM survey meter manufactured for the Atomic Energy Commission in the late 1940s by El-Tronics Inc. of Philadelphia. The only model number on it is SGM-18A, a designation used by the Atomic Energy Commission. Volume IV of the military's Radiological Defense shows a picture of this unit and states that the El-Tronics model number is SM-3 and that the military designation is AN/PDR-26. The AEC's Radiation Instrument Catalog Number 2 (with a page date of July 1, 1950) shows the SGM-18B, but not the SGM-18A. A 1950 El-Tronics advertisement in Nucleonics for their Model PR-3, which is obviously the same as the SGM-18B, describes several "new" features. Although not stated as such, these features are in clear contrast to those of the older SGM-18A (aka the SM-3 or AN/PDR-26).

El-Tronics SGM-18A GM Survey Meter (late 1940s)

Range: 0-0.2, 0-2.0, 0-20 mR/hr

Size: ca. 4 1/2" x 9" x 6"

Output: No speaker but it has a phone jack

Batteries: This baby is packing a serious set of batteries—two 45 volt "B" cells, one 1.5 volt radio "A" cell, and three 300 volt cells


  • Atomic Energy Commission Radiation Instrument Catalog, Catalog No. 2, Part 2, page date July 1, 1950 , page SGM-18B.
  • Advertisement. Nucleonics, August 1950, page 97.
  • Campbell, D.C., Radiological Defense, U.S. Armed Forces Special Weapons Project, Volume IV, 1950.