This communication proposes a compact, high performance, quadruple-ridged flared horn operating from 8 to 50 GHz. A prototype fed by two coaxial connectors has been designed and fabricated based on the combination of a four-petal structure and a back plate. Measurements show that the input reflection coefficients are below −10 dB over more than 6:1 frequency range. Radiation patterns were measured in an anechoic chamber, and good agreement was found with the simulation results. Physical optics calculations predict an average of 68% aperture efficiency with the feed installed on the square kilometer array shaped offset Gregorian reflector. The horn is a good demonstration at very high frequencies of a wideband feed for radio telescopes.