Abstract: A multichannel correlation receiver at an earth station is provided for determining the depolarization effects of atmospheric conditions on satellite communications. The receiver provides a first co-polarized signal and a second, relatively weak, cross-polarized signal indicative of the depolarization effects, and uses a phase locked loop demodulator to produce a noise free replica of the relatively strong co-polarized signal. This co-polarized signal is highly correlated with the second cross-polarized signal and is mixed therewith to provide a relatively noise free, narrow band signal which has a level indicative of the cross-polarization signal strength for both up-link and down-link propagation paths. The relative signal strengths are recorded on a digital storage means and provide an accurate measure of the depolarization effects of the existing atmospheric conditions. A programmable local oscillator also provides multiple channel capability.