Although I posted out of memory, I think the essence of the 'area rule' is pretty much captured. I never asked the antenna to be mounted reversed.
The antenna is really fat and chopped flat at the trailing face. this is not really good aerodynamically. If that face were smooth rounded, it would indeed be better to mount it backwards. That is demonstrated clearly in
this thread by Craig Vetter, the motorcycle aeromodder. The thread initiator did not just pull that question out of his hat.
It is good to note that the 'compressibility' factor that makes the real difference about applicability of the area rule though. Thanks for pointing it out.
So the slow moving down to earth car should really be moving through a
compressible fluid, rather than incompressible, right? Its the shockwave that makes it incompressible.