From the Wikipedia:
Microwaves are a form of electromagnetic radiation with wavelengths ranging from one meter to one millimeter; with frequencies between 300 MHz (100 cm) and 300 GHz (0.1 cm).
With that amplifier being in the 440 Mhz Ham band, at 100 watts of power, you will have the active element of a microwave oven. You want to check the safety concerns of your Ham License (you are licensed?) to see just how far you will have to be from it to avoid cooking yourself.