Measurements of a 150 to 1700 MHz low loss Eleven feed for the 42 m radio telescope at Green Bank

We present measured results for a dual polarized 150 to 1700 MHz Eleven feed for use in the 42 m radio telescope in Green Bank. The feed is manufactured from a 3 mm thick aluminium plate and located inside a steel container with a soft radome over its opening. The feed provides dual polarization and more than a decade bandwidth. The aperture efficiency in a primary feed reflector system is better than -2.25 dB over the entire band, and the input reflection coefficient is better than -7.0 dB. The losses have been computed and measured and are lower than the measurement accuracy of -0.5 dB over the entire band. The coupling between the two polarizations is lower than -29 dB across the entire band. The results agree well with computed values