Mapping the absolute brightness of the sky at low frequencies

Uncertainties in the gain and zero‐level of the existing radio and microwave frequency sky surveys often dominate the error budget in studies of anisotropies and spectral distortions of the Cosmic Background Radiation.This paper discusses our existing prototype and the planned instruments and the observation techniques which are necessary for conducting an extended observational campaign to map the total sky brightness. Some experimental difficulties are outlined, and possible solutions are given.