Since today the HiQSDR or the original N2ADR frontend might be used as a vector network analyzer for the shortwave range.
Jim wrote a simple tool that displays amplitude and phase between TX port and RX port and can handle some calibration.
Currently it is quite simple and i do not have provisions to measure reflections yet, so i can just measure S21 at the moment.
But for the future it will be a nice feature to have the antenna analyzer built into the transceiver itself.
The picture below shows a simple ugly-style lowpass filter.

HiQSDR as VNA