Let a monochromatic plane wave impinge on a collector of area A, delivering power P. Let the average photon rate of arrival on the collector be B. Now make the collector move toward the source at velocity v. By the Doppler effect, the frequency, and hence the energy, of the photons will increase by a factor r = 1+v/c. This increases the collected power by the factor r. So far, so good. However, the photon rate of arrival is also increased by r, making the total power increase r^2. That can't be right. I suspect the problem is that the photon interception rate does not really increase, probably because their velocity relative to the collector is still c, but don't understand this. If the wave packets get squashed, why doesn't the photon spacing?