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Communication Electronics, Inc

Bethesda and Rockville, Maryland

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CEI SM-8512-6 Signal Monitor

Front Inside With R-390A Provisioning information
SM-8512 data sheet   R-390x modification instructions to tap 455 kHz IF before the IF filters

This is a Communications Electronics, Inc SM-8512-6 signal monitor (SM). It was designed for surveillance use with the Collins designed R-390(A) series of radios. It came with instructions for modifying the R-390(A) for wideband IF output. This unit has a 455 kHz IF and can display 5, 20 or 50 kHz of the spectrum. It uses nuvistors throughout the signal chain and a few early germanium transistors in the power supply.

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To properly use an R-390 radio with this analyzer, a pre-IF filter output must be installed. CEI provided detailed instruction in the SM instruction manual. It makes a wonderful addition to the R-390 radio and is probably one of the rarer accessories.

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Construction on early CEI equipment set new standards in radio design elegance. From the gold subchasses and minaturized circuits using nuvistors to the clean layouts and efficient designs, CEI equipment broke the "heavy iron" mold that characterized most radio equipment produced for governmental agencies. This quality of construction of elegance of design continue to this day under the WJ name.

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The government purchased an unknown quantity of these SMs for three branches.

CEI model Nomenclature NSN Buyer Contract Notes Date
SM-8512 IP-861/URR 5820-00-105-3064 Air Force F41621-73-C-0075   2-73
SM-8512-1         IF changed to 5.94 MHz  
SM-8512-2         input for two receivers  
SM-8512-3         special color front panel, rack slides  
SM-8512-4 IP-866/URR 5820-00-933-7909 Navy NOM73611 modified for use with R-390A, quick disconnect power connector, input for three receivers 7-66
SM-8512-5 none none NSA DA18-119-AMC-03432 gray front panel, input for two receivers, built for Sylvania 1-67
SM-8512-6         zero span push button added  
SM-8512-7         IF changed to 370 kHz  
SM-8513         dual 8512 designed for use with R-390  

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