On Wed,7/8/2015 7:30 PM, Richard (Rick) Karlquist wrote:
I am not sure what Jim means by a "full" VNA. There are a growing
number of low cost analyzers that have the same architecture as
this one, which combines a 1 port network analyzer with a 2nd receiver
port. These devices can sort of measure S11 and S21, but do not
offer full two port calibration with 12 term error correction like
"real" network analyzers do. Depending on what you are doing, these
limited analyzers might make acceptable measurements. Or they may
have unexplained response ripples.
It's not a $50K Agilent (or whatever they're called this week). But
it's good enough that N0AX was going to give it a glowing review in QST
(and buy one for himself) until WX0B yelled about patent rights. And
it's good enough that when AC6P, a prof at UCSC, did a repair on mine by
replacing some SMT parts, he liked it enough that he bought one for
himself.
And -- the calibration routines seem to be well thought out. Take a look
at the manual, which is online.
Specific to VNWA3, the output level is only -17 dBm. This weak drive
level is unlikely to do well when measuring 160 meter antennas in
the presence of BCB QRM. Again, this may or may not be an issue
depending on your circumstances.
Agreed.
It goes to 1.3 GHz, but with reduced accuracy at high frequencies.
As I read it, it's reduced dynamic range.
I don't like the axis scaling and labeling in the GUI.
Yes, it's typically German. I had similar issues with acoustic modeling
and measurement software for which I was a beta tester. But the
developers, who had become personal friends, implemented my suggestions
for improvements.
The competition in this space seems weak compared to this model,
so it may be best in class, but realize its limitations.
So far, the only limitation I've run into is that the I/O can't handle
much RF. :)
73, Jim K9YC
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