Extragalactic radio sources polarization

The excellent telescope optics of the Effelsberg 100 m telescope at this wavelength, combined with a matrix method we applied for calibrating out all components of the instrumental polarization enables us to achieve better than average accuracy in the determinations of linear polarization degree and position angle.

In the absence of thermal noise errors, these are repeatable to better than 0.2% and 0.1{deg} respectively, for the prime calibrator, 3C 286.