Using Dislords firmware, the LiteVNA supports I think unlimited harmonics, or at least way beyond what is useful. If I wanted to measure S11 directly rather than using the frequency extender, at least for the X-band and my particular versions of hardware, we can't. Using the supplied cables, short, open and sorted mini-circuits load to calibrate the VNA from 1M to 9GHz. Plot showing the return loss with the standard attached. Even at 9GHz, the return loss is basically 0.