Winston wrote:

I figure a 200 W microwave amplifier should result in ca 100 KW ERP at
the feed horn of a 30" diameter parabolic dish.

You may be confusing ERP and presumably ERIP (power relative to that
radiated by a dipole or an isotropic radiator respectively) with raw
power. ERP is the amount of power you would have to feed to a dipole to
get the same energy that the directional antenna delivers to a given
area. A high gain antenna does not generate power; it puts a given
amount of power into a smaller area. If you need 200 Watts of power
coupled into something for some purpose, you will need to feed the
antenna with a lot more than 200 Watts.


Kevin Gallimore