Tom Donaly wrote
So in the limit, as the number of radiators is increased to infinity,
the amount of power it would take to produce the measured sum would go to
zero.
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As the number of radiators in a given array never can reach infinity,
neither will the input power for a given peak ERP from that array ever go to
zero. Obviously there are practical limits as well.

But this does not change the realities that...

1) other things equal, the greater the number of discrete radiators in an
array, the less input power is needed for that array to produce a given peak
ERP, and

2) the peak free-space, far field produced by a given ERP is the same for
all combinations of antenna gain and antenna input power producing that ERP.

This has been proven in commercial FM and TV broadcast systems for many
decades.

RF