  In this paper, we revisit Radlow's innovative approach to diffraction by a
penetra ble wedge by means of a double Wiener-Hopf technique. We provide a
constructive way of obtaining his ansatz and give yet another reason for why
his ansatz cannot be the true solution to the diffraction problem at hand. The
two-complex-variable Wiener-Hopf equation is reduced to a system of two
equations, one of which contains Radlow's ansatz plus some correction term
consisting of an explicitly known integral operator applied to a yet unknown
function, whereas the other equation, the compatibility equation, governs the
behaviour of this unknown function.
