> Pathloss(in dB) = 36.6 + 20*Log(F) + 20*log(D)
>
> where D is in statute miles and F is in MHz.

OK, Jim, I'm not an RF expert like you, but this just seems contrary to the
laws of physics to me.

The 36.6 term is a scale factor to account for the specific units chosen.
I'll trust you figured this out correctly.  The 20*Log(D) term says the
signal is attenuated a fixed multiple for each unit distance.  I was
expecting the inverse square law here.  The 20*Log(F) term says that there
is an additional fixed attenuation multiple for each unit increase in the
frequency.  That makes no sense at all.

Did you perhaps copy the equation for something like signal loss in a
transmission line or resistive media?  The original poster was asking about
RF communication which I took to mean propagation between antennas.  I was
expecting equations for the propagation of electromagnetic waves in free
space.  What am I missing here?


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