GcMid1960s

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GcMid1960s

A relic from the Cold War nuclear jitter, a Geiger Counter's manual

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An escalatorhi.com web page by Jim Cline.


Background: Circa 1980 I bought an old surplus Geiger Counter. Although the over-hundred-volt batteries for it were no longer available, I was able to create a virtual battery for the high voltage for the vacuum-tube instrument by stacking 15 of the conventional 9 volt batteries together, and was able to use the instrument to measure the radiation in my environment. There seemed to be a high energy source of some kind occasionally toasting my immediate environment, source or type unknown. Unfortunately I was not able to have the Geiger Counter running at any time and place when the "energy beam" was toasting things including parts of me, so was not able to confirm its nature re nuclear energy sourcing or misuse of a structural inspection X-ray generator.


I recall using a similar instrument during my training to be a Radiation Monitor back in the mid-1960's. The training taught how to use the instrument to locate areas of lesser radiation in case of a nuclear blast nearby that one had happened to survive. Part of training graduation was for all trainees to share in eating from a can of beans that had been subjected to severe radiation from our radiation sample used in the training course, to show we were confident of the edibility of contents of sealed canned goods, an important bit of knowledge in case things have been smashed all around your area. If I can find my copy of handouts of how to build a fallout shelter depending on circumstance material and time availability, I will add it to these Historical Items pages. People nowadays do not usually have the sense of any moment being bombed by a nuclear weapon, and how to deal with it rationally to optimize long term survivability of self and others. 


The instrument is still in my possession (as of April 25, 2008; the world has gotten weird again, so who knows of tomorrow here) although the old GC instrument is not currently working. Perhaps its manual's pages would be of historical interest to others, however; and so below are some representative pages from the manual and other related written material. Enjoy.


pdr27Cover.jpg

Cover of the manual for the "Radiac Set AN/PDR-27F" Geiger Counter.


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First page of the Table of Contents


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Contents of the instrument's waterproof case.


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pdr27picturep1-5.jpgpdr27picturep1-7.jpgpdr27picturep1-8.jpg


pdr27theoryopn2-1.jpgpdr27theoryopn2-2.jpgpdr27theoryopn2-4.jpgpdr27theoryopn2-10.jpg


pdr27operation4-2.jpg

pdr27maint7-13.jpgpdr27maint7-15.jpgpdr27maint7-16.jpgpdr27maint7-17.jpg

pdr27parts8-27.jpg

pdr27mfgrlist8-37.jpgpdr27mfgrlist8-38.jpg


pdr27schematic.jpg


pdr27wiringDiagram.jpg



pdr27colorCodes.jpg

Color codes used on parts in the instrument.


pdr27calibration1966.jpg

Original calibration card, showing calibration in 1966.

pdr27addendum&jedcCalib.jpg

Overlay of my personal first calibration note, on top of an addendum sheet of the type used back then for a field change, T-2 to NAVSHIPS 91856, dated 29 March 1954. And my calibration overlay shows that my glowing-hands night-readable wristwatch, which I had worn day and night for decades, was producing between 1.5 to 3 mr/hr.


Copyright © 2008 James E. D. Cline. Permission granted to reproduce providing inclusion of a link back to this site and acknowledgment of the author and concept designer James E. D. Cline.