I am an RF / microwave engineer with over 40 years experience.  I have used numerous high end VNA's and written calibration and load pull software.
I just received a NanoVNA6000-A.  I can cal the unit locally and get measurements that look reasonable (3.5 GHz bandpass filter). Cal is 3.4 to 3.6 GHz
with 201 points. When I connect the QT software the frequency sweep is stuck at 200 MHz to 1450 MHz and never updates.  I re-did the cal from the
QT software and still no change in frequency.  I flashed the latest firmware with no change.  I think I actually had the latest to start with.
Running up to date Windows 10 on a Dell notebook.  I have the dll files in the same directory with the exe file. Do they need to go to Windows
or SysWOW directory?

With the Saver software, I get the frequency sweep I set on the unit.  And I can cal from Saver and see results very similar to the local cal.
I have different questions about Saver that I will address later.

Dan
www.dgsboulder.com ( http://www.dgsboulder.com )
K0DGS