A 1200 watt microwave is essentially like a 1200 watt bar heater if you're outside the oven cavity. To a person, it will feel pretty warm at a distance of a few feet as the energy is basically unfocused as it exits through the open door.
But to a drone, it's 1200 watts of RF noise near a receiving device that's tuned to listen for signals that are typically around 0.00000001 watts. It would be like trying to hear a pin drop at a rock concert.
Do need to make sure you point it upwards though as it will cause havoc with microwave motion sensors and a bunch of other sensitive listening stuff. Also, good luck getting wifi within a hundred metres of it.