Use transport theory we have calculated the radar cross section of an underdense turbulent wake in the limit when the scale size of the turbulence is larger than the signal wavelength. We have found that for bistatic scatter the first Born approximation is valid, even if the wake is many photon mean-free paths in extent. However, neither the Born approximation nor the modified Born approximation is valid for the nonostatic radar cross section when the wake is many photon mean-free paths in extent. In this case a modified result, derived in this report, must be used.