Hence the popularity of the <$100 NanoVNA in various flavors, particularly for
HF. (True, the 4" display version is $110 at R&L electronics, the NanoVNA-H is
$80)
Yes, they're all made in China, but my NanoVNA (original), TinySA, etc. have
all done just fine.
The original NanoVNA (in both the 2.8" and 4" screen versions) is fairly robust
to ESD on the inputs - they're resistive bridge or pad - the NanoVNA2 is less
so (it has an electronic switch on the inputs, which is vulnerable)
On Wed, 11 Feb 2026 16:55:19 -0700, Tom Hellem <tom.hellem@gmail.com> wrote:
Man, have I learned a lot about analyzers vs. vna's since yesterday.
All of you folks in this group who have responded have given me a wealth
of information.
Yes it seems few or none of the typical analyzers have the capability
to do the SOL compensation.
I see that the new(er) RigExpert Match for about $300 can do it
after purchasing a "license" for an additional $80.
There is also the FA-VA6 by Funk Amateur in Germany for a little less money.
Amazon lists a big pile of nano-vna's starting at about $80 and
up to around $700. I'm a little leary of them due to the made in
China factor, but could be convinced otherwise by someone who
has owned one for a while.
Anyway thanks a bunch to all who have weighed in on this.
Hopefully I am not the only one who received some benefit from
y'all.
Tom
K0SN
On Wed, Feb 11, 2026 at 2:57 PM Richard Karlquist <richard@karlquist.com> wrote:
What you are looking for is the "port extension" feature, which is "only
software" but nevertheless is missing from many implementations. (Back
in the stone age, port extension was a hardware feature implemented with
a mechanical line stretcher, but now is pure mathematics). It's not as
good as actually doing SOL at the end of the coax of coarse and depends
on knowing the physical length of the coax and its velocity factor.
Some implementations have a TDR function that allows you to determine
these numbers for coax that is already up on the tower. Then you can
enter them into the port extension feature.
In a prior life I designed network analyzers for Agilent.
---
Rick Karlquist
N6RK
On 2026-02-11 12:32, Jim Lux wrote:
> Almost all of the current inexpensive VNAs can do this.
> It's the de-embedding of the coax that might not be automated (unless
> you cal at the end of the coax, which is inconvenient if the end of the
> coax is at the top of the tower). Not all the VNAs have the ability to
> "subtract out" the transmission line. Most of the programs that run on
> a computer that talk to the NanoVNA and its ilk can do this.
>
> On Tue, 10 Feb 2026 11:40:20 -0800, Jim Brown
> <jim@audiosystemsgroup.com> wrote:
>
> On 2/10/2026 11:03 AM, Jim Lux wrote:
>
>> This is where tools like the NanoVNA are really nice - you can
>> calibrate at the end of the coax. Or, if you've measured the coax
>> once, you can save it, and post process your data in one of the apps
>> that takes VNA data (I use NanoVNA-Saver, but there's lots of others).
>
> A common use of analyzers is to simply use the SWR as a rough indicator
> or resonance. The best can export a measurement as a data file (plain
> text) that can be imported by freeware like SimSmith, which can then
> "tune out" the coax by inserting a length of coax and varying its
> length
> until we see the normal Smith Chart view of resonance. I've used that
> model to design switchable stub matching networks for my 80 and 40M
> dipoles on the CW and SSB portions of the band. I've also used the
> model
> to optimally place along the line stubs to suppress power amp
> harmonics,
> and to eliminate interaction between harmonically related antennas in
> close proximity. See k9yc.com/7QP.pdf for an example.
>
> For more than ten years, I've used the VNWA, built by hams in the UK
> based on a design by German EE prof DG8SAQ, and using his control
> software. That software can do that transformation and a lot of other
> math, like transforming a measurement of an antenna fed by 75 ohm line
> to show its true impedance.
>
> 73, Jim K9YC
>
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