The SCR-277 was a mobile, trailer mounted radio range set for radio guidance of aircraft. It was standardized by the U.S. Army in June 1941.
K-29 trailer for SCR-277, 1944
A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, γωνία 'angle' and μέτρον
Goniometer made by Develey le Jeune in Lausanne, late 18th–early 19th century
A half-circle protractor marked in degrees (180°).
A half-circle bevel protractor
A universal bevel protractor.