Yes that frequency term is precisely the sketchy bit. Because of that the equation doesn't conserve energy which is normally considered a bad sign. On the oth

Yes that frequency term is precisely the sketchy bit. Because of that the equation doesn't conserve energy which is normally considered a bad sign. On the other hand to do it properly you have throw out the 'reciprocity' of sending and receiving antennas. They are not really the same at all.