Jitt wrote:

Only in theory. It is possible to write an expression
which relates an increase in Tx power to Rx antenna power at
the remote site, but I doubt if it would agree with observed
values in the field.

And this is one place (of pretty much all in RF) where theory absolutely
matches reality. Your doubts are misplaced.

Could you please give us an example, with all relevant data, where they
did not agree?

tom
K0TAR