Thank you for the quick reply! It is much appreciated. I am simulating the scattered power from a small, extremely high Q resonant scatterer, which is resonant near 1 GHz. Because it is so high Q, it will take a long time for the fields in the resonator to decay, which means the autoshutoff time is already fairly long. However, I am wondering if I will need to run the simulation for perhaps a longer time in order to obtain the spectrum of the scattered power with high frequency resolution near the scatterer resonance.