[vna] VNA User Observations

[Christopher Smith]

I should say from the outset that I love having this VNA available at
such a reasonable price. I don't mean to be critical, but I hope to
help improve the software and "user experience."

Is the source code for version 2 going to be available soon? Will it
compile with  Visual Studio 2005 Express?

I find the detector calibration directions confusing. I think choosing
this calibration sets the frequency range, integration and number of
points - but the manual and help files don't say so. The manual could
remove those points of confusion.

In use, frequency entry is awkward. I like the interface found on some
of the HP models: select start or stop, enter a number (with decimal
point), then choose "MHz," "KHz," or "Hz." I can code it in Fortran
and Visual Basic 6, and maybe VB 2005.

The scales seem to be off. Under Trace and VertScale, choices can be
made that don't seem to be reflected in the display. For example, if I
choose Trace = S11 Magnitude (rectangular) and then VertScale = SWR 1
to 11, the right scale displays SWR markings but the S11 (dB) scale on
the left remains unchanged, the trace is in dB, and the SWR scale on
the right does not match the scale on the left. I would expect the
scale to be linear in SWR and the dB markings on the right to change
to correspond with the SWR. (Except at SWR=1, and then S11=-100dB will
do nicely.)  Instead, 0dB is SWR=11, -50 dB is SWR = 6, etc. Clearly
something is wrong or I am missing the point of the display.   Again,
I would be happy to help program the math, though I am rusty on the
Visual Basic/C++ side of things.

I also think the polar displays have problems.

Still, the unit was a great help in setting up my 10m Ringo Ranger
this past December, and will ultimately be of great benefit to the
ham community.

73,
Chris, NX0E