Product Details:
Perhaps the only Automatic Bearing Indicators in existence today and new in the crates to boot. Made by Federal Telegraph for WWII and delivered March 31, 1942, right in the thick of it. New technology was being pushed to the edge of the envelope. I suspect they never were adopted as standard equipment. Includes prototype style handmade manual (original and marked restricted of course) with each scope.

Basic theory of operation is a small 1/8 HP 1140 rpm motor drives a goniometer directly and a set of magnetic deflection coils. A 5BP1 CRT is positioned inside the rotating deflection coils and thereby deflected. An optical system consists of an illuminated scale and a mirror so positioned that the reflection of the scale appears to coincide with the pattern obtained on the screen of the CRT.

The manual indicates the following voltages are required:  -800v DC, -650v DC, -160v DC, -135v DC, 6.3v AC and 11 5vac 60 Hz. Only four available. 120 pounds gross weight. 46" long.