I'm trying to upgrade my fission reactor power microwave network to fusion reactor power and I have a problem to maintain plasma heating of transmitting station. I define designs in sandbox mode (interstellar mod is very complete and sometimes very hard to understand and sandbox helps me) but the problem happens even in career mode. On a transmitting station, I designed my transmission station with a 3.75m fusion reactor connected on each side to a electrical generator (KTEC on a side and Direct conversion on the other side)(a KW is a KW ^^). A docked 2.5m fission reactor and 2.5m electric generator is used to start fusion reactor and perform orbital maneuvers (with a thermal rocket nozzle). At the Deployable Phased Array Microwave Transceiver transmit mode activated, a warning is displayed "Fusion Reactor plasma heating cannot be guaranteed, reducing power requirements is recommenced". As piority value on Megajoule demand on plasma heating is lower than microwave transmitter, I was hoping that everything remain stable. Unfortunately not ... Returning to space center shut off fusion reactor (not the case when vessel is maintained focused). Someone can explain me where I failed ? Or a way to limit beamed power ?