A conically-scanning antenna is described which consists of a scanner mechanism, rear feed, and 8-foot diameter parabololoid producing a pencil beam having equalE-andH-plane beamwidths. The polarization may be quickly changed from linear to circular to vertical polarization. The sense of the polarization is readily changed from left-hand to right-hand. The replacement of one section of transmission line by a half-wave plate changes the unit from a nutating polarization scanner to a twice-scan-speed rotating polarization scanner. The scanner incorporates some novel features such as a symmetrical rear feed having equalE-andH-plane patterns, high-power quarter-wave and haft-wave plates, and an orthogonal mode absorber. This paper describes the techniques which were employed to obtain the above mentioned performance. The problems encountered and their solutions are described.