With my SolarEdge inverter I have ferrites on the solar panels and the optimizers where they join loop to the inverter.I also have an EMI filter in the AC line to the main breaker box.
All of that to try to keep the interference FROM the solar system to a minimum.
The post from Ron is correct in that the RF from the transmit antenna is getting into the inverter control system.
I suggest that you try adding filters to the control inputs and the power inputs and outputs.
You did not say what power levels you are working with, but I found a 60 amp EMI filter for the AC output that installed in a 6" X 6" X 4' trough from the inverter to the main box. There is room there to add some more ferrite chokes if necessary.
I suspect that if the solar panels feed the inverter their wiring is the most likely source of the problem. When I installed mine I kept the wiring for the + and - twisted together to make a differential power line like an RF transmission line to limit radiation which would also limit pickup of RF interference much better than a loop from panel to panel as is often done. Looping a single power wire from panel or optimizer to the next and then back to the inverter creates a very nice loop antenna operating in common mode.
More information is necessary to decide what would be the best course of action.
JD
KE4MD
