El-Tronics PR-5A GM Survey Meter (1955-1960)
This GM survey meter was manufactured by El-Tronics Inc. of Philadelphia sometime in the mid to late 1950s.
Unlike the Model PR-5, which had an external probe, the GM tube of the PR-5A is located inside the case—the detector window can be seen in the lower right hand corner of the case in the above photo. The glass-walled GM tube was manufactured by RCL.
Quoting a 1955 advertisement: "Three Range Portable Geiger Counter. Highly sensitive, with internally mounted G.M. tube designed for prospecting under rugged conditions! Waterproof meter. Flashlight batteries. Comes with strap. Alnico magnet earphone. Model PR-5A - $99.95."
Range: 0-0.2, 0-2.0, 0-20 mR/hr
Size: ca. 4" x 8" x 4"
Output: No speaker but it has a phone jack and a neon light the flashes of which indicate the count rate.
- Atomic Energy Commission. Radiation Measuring Instruments, RIB-8 (supplement 2). July 1, 1954. Page SGM-111A.
- Advertisement. Saturday Evening Post. July 16,1955. Page 87.