Direction finding (DF), or radio direction finding (RDF), is the measurement of the direction from . They built groups of five DF stations, so that bearings from individual stations in the group could be combined and a mean taken. Four such
3310 D Double row angular contact ball bearing with a two-piece inner ring; K 40×45×17 D Polymer ball bearings with a component made of Ceramic ZrO2.
Angular contact ball bearings are non-separable type bearings of series 79, 70, 72, 72B, 73 and 73B. The line connecting the contact points of the steel ball and
This document is an exhaustive analysis of RDF bearings from various sources, by Bob Brandenburg. The paper is mounted on this site in several sections; the