By analysing slant path propagation events observed using the 20GHz sw
itched polarisation beacon of the Olympus satellite, it is shown that
the phase offset on transmission between the two polarisations was app
roximately 49 degrees, with the near-vertical polarisation lagging. Kn
owledge of this offset makes it possible to determine the medium trans
mission matrix with all terms properly calibrated in their relative ph
ase.