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When you calibrate the Nano (on device calibration) in the range as the
documentation
suggests 0-900MHz with 401 points and then calibrate using the NanoVNA
Saver in the same
range using, for example, 2000 points the Saver will get the interpolated
results from the
device, not raw values. Same goes if you change the range. This, obviously,
leads to errors.
Remove the calibration and save that to the default slot (0 slot) when
using NanoVNA Saver.

On Sat, 26 Apr 2025 at 19:39, Dean W8ZF via groups.io <dwfred=
[email protected]> wrote:

Thanks Dave,
So if the H4 internal cal is *independent* of the nanovna-saver cal,
exactly what are you clearing with nanovna-saver's "clear all cals"and when
would that be necessary?
I ALWAYS either calibrate prior to measurements (and upon any sweep range
or source power change) or I alternatively load a saved calibration file
generated by nanovna-saver. Doesn't using the calibration assistant or
loading the cal file "clear all cals"?

I understand the principles and use of a VNA. I'm a Senior Principal RF
engineer and have used professional VNAs for 45 years. But I am new to
the nanovna VNA implementation and the interactions of the H4 with software
interfaces. What would be the source of information on whether
nanovna-saver uses raw data from the nanovna as part of its calibration,
nor not? I can always use the internal calibrate routine in the H4 for
mobile use, it looks like that's necessary (since the nanovna-saver cal
data is independent). But I am still not convinced that I can trust
nanovna-saver's calibration (because MAYBE it depends on the H4's cal
state).

Thanks and 73,
Dean W8ZF

Dragan,
This just confuses me again.

"Remove the calibration and save that to the default slot (0 slot) when
using NanoVNA Saver."

Remove *which* calibration? And save *what* to slot 0? Are you talking about the H4 device? Do you mean from the calibrate menu, choose "Reset" and then "Save" to memory 0?
What values does this put into memory 0? And since nanovna-saver depends on the calibration of the H4 device, what is that calibration now (after reset and store 0)?

"When you calibrate the Nano (on device calibration) in the range as the
documentation suggests 0-900MHz with 401 points..."

Where is there an option on the H4 device to select the number of points used for calibration? I haven't seen that as a menu option.

If the calibration of nanovna-saver gives different results, depending on the state of the H4's calibration, I don't know what to believe.
Forgive me, I still don't understand how this works together. I don't see why nanovna-saver can't just read raw results from the H4, and then use those for a calibration (which would make it independent of the H4's calibration). There have been some mentions about different numbers of points, about reporting invalid values, etc.

Does anyone KNOW, not guess, what the proper procedure to calibrate this system using nanovna-saver is? Nanovna-saver is what it is, I'm not bashing it or trying to change it -- I'm just trying to understand the limitations and requirements to get good results out of the software. The ability to store calibrations, write s-parameter files, and plot using different formats is invaluable to me. I *really* want to use it for these features, but not if I can't be sure of the measurement.

73,
Dean W8ZF

Can anyone direct me to the latest SAFE version of nanovna-app? I went to GitHub and found a branch under DiSlord. There is a Win32 release of NanoVNA-App.exe from 2 months ago. When I try to run it, it fails the MS Defender malware scan. That is common for many apps that don't pay MS for the "safe" tag, so it may be fine. I just wanted to verify before I bypassed the warning and ran it.
Thanks,
Dean W8ZF

I'm real time on my H4, so hope this maps to yours.

QUOTE (Dean, W8ZF): This just confuses me again. "Remove the calibration
and save that to the default slot (0 slot) when using NanoVNA Saver."

Remove *which* calibration? And save *what* to slot 0? Are you talking
about the H4 device? Do you mean from the calibrate menu, choose "Reset"
and then "Save" to memory 0?
What values does this put into memory 0? And since nanovna-saver depends
on the calibration of the H4 device, what is that calibration now (after
reset and store 0)?

"When you calibrate the Nano (on device calibration) in the range as the
documentation suggests 0-900MHz with 401 points..."

Where is there an option on the H4 device to select the number of points
used for calibration? I haven't seen that as a menu option.

Calibrating on the native NANOVNA, there is no choice for number of
points. I believe it will default to the maximum number of points which is
401 (??).

Always remember to "RESET" before a new calibration.
***

If the calibration of nanovna-saver gives different results, depending on
the state of the H4's calibration, I don't know what to believe.

It depends on how different the results are. Remember, the FW interpolates
between measured and stored cal values. Saver can be configured with 1001
points so the cal. sampling is much finer than a cal. on the native NANOVNA
(without SAVER).
***

Forgive me, I still don't understand how this works together. I don't see
why nanovna-saver can't just read raw results from the H4, and then use
those for a calibration (which would make it independent of the H4's
calibration). There have been some mentions about different numbers of
points, about reporting invalid values, etc.

Again, using SAVER, there is the option to use considerably more points for
calibratioin: Native is 401 points, SAVER allows up to 1001 points. So
extrapolation between measured points using the two calibrations will be
coarser with the native VNA cal than with the SAVER cal.

If you simply were able to upload the native cal (H4 alone) to SAVER, you
would not take advantage of a number of additional measurements and
presentations. SAVER is considerably more powerful than the FW within the
native NANOVNA.
*


Does anyone KNOW, not guess, what the proper procedure to calibrate this
system using nanovna-saver is? Nanovna-saver is what it is, I'm not
bashing it or trying to change it -- I'm just trying to understand the
limitations and requirements to get good results out of the software. The
ability to store calibrations, write s-parameter files, and plot using
different formats is invaluable to me. I *really* want to use it for these
features, but not if I can't be sure of the measurement.

Once you have "woke up" your NANOVNA by a native calibration, connect and
run SAVER. Treat SAVER as a totally independent set of FW/SW from that
within the NANOVNA. SAVER has all the options to connect, reset, do a
complete cal potentially with more points than the native NANOVNA can
support. Again, SAVER offers much more capability the the FW embedded
within the native NANOVNA.
***

General Comment: Remember we are not expecting metrology lab comparisons
between the native NANOVNA and the SAVER results/measurements. Differences
with carefully and faithfully duplicated setups, disagreements in the first
significant figure, or maybe in the second, should be of little concern.

For example, if you measure a single 50-ohm resistos with three different
DMMs, you will get three different results. Here you go using a stock
50-Ω, 3%, 1-watt resistor:
[image: image.png]


INSTRUMENT MEASURED VALUE (Ω)

HP 3478A 49.994

Cen-Tek P37772 50.1xx

Sperry DM-6400 49.8xx

HP 4261A LCR Mtr 50.8xx

Well, which one would you pick? Is it a 50-Ω resistor? None of the
measurements indicate it's 50-Ω. Is it within the 3% specification of ±1.5
% or ± 0.75 ohms? Yes, by three of the four measured values made on four
different instruments.

Dave - W?LEV

On Mon, Apr 28, 2025 at 8:25?PM Dean W8ZF via groups.io <dwfred=
[email protected]> wrote:

Dragan,
This just confuses me again.

"Remove the calibration and save that to the default slot (0 slot) when
using NanoVNA Saver."

Remove *which* calibration? And save *what* to slot 0? Are you talking
about the H4 device? Do you mean from the calibrate menu, choose "Reset"
and then "Save" to memory 0?
What values does this put into memory 0? And since nanovna-saver depends
on the calibration of the H4 device, what is that calibration now (after
reset and store 0)?

"When you calibrate the Nano (on device calibration) in the range as the
documentation suggests 0-900MHz with 401 points..."

Where is there an option on the H4 device to select the number of points
used for calibration? I haven't seen that as a menu option.

If the calibration of nanovna-saver gives different results, depending on
the state of the H4's calibration, I don't know what to believe.
Forgive me, I still don't understand how this works together. I don't see
why nanovna-saver can't just read raw results from the H4, and then use
those for a calibration (which would make it independent of the H4's
calibration). There have been some mentions about different numbers of
points, about reporting invalid values, etc.

Does anyone KNOW, not guess, what the proper procedure to calibrate this
system using nanovna-saver is? Nanovna-saver is what it is, I'm not
bashing it or trying to change it -- I'm just trying to understand the
limitations and requirements to get good results out of the software. The
ability to store calibrations, write s-parameter files, and plot using
different formats is invaluable to me. I *really* want to use it for these
features, but not if I can't be sure of the measurement.

73,
Dean W8ZF

--

*Dave - W?LEV*


--
Dave - W?LEV

On Mon, 28 Apr 2025 at 22:25, Dean W8ZF via groups.io <dwfred=
[email protected]> wrote:

Dragan,
This just confuses me again.

"Remove the calibration and save that to the default slot (0 slot) when
using NanoVNA Saver."

Remove *which* calibration? And save *what* to slot 0? Are you talking
about the H4 device? Do you mean from the calibrate menu, choose "Reset"
and then "Save" to memory 0?
What values does this put into memory 0? And since nanovna-saver depends
on the calibration of the H4 device, what is that calibration now (after
reset and store 0)?

Yes, memory 0 should store the uncalibrated state, essentially no

calibration. Saver takes whatever the device gives it, there is nothing in
the serial protocol commands that deal
with calibration data.

"When you calibrate the Nano (on device calibration) in the range as the
documentation suggests 0-900MHz with 401 points..."

Where is there an option on the H4 device to select the number of points
used for calibration? I haven't seen that as a menu option.

I believe that it takes the number of points set on the device. I never use
the device standalone so I don't remember which option it is.

If the calibration of nanovna-saver gives different results, depending on
the state of the H4's calibration, I don't know what to believe.

It's simple: NanoVNA has a simple serial protocol, you can set the
basic parameters, request the scan etc. If your on device calibration
is completely off you will get bad results without or with Saver
calibration since it's working with bad data from the start.

Forgive me, I still don't understand how this works together. I don't see
why nanovna-saver can't just read raw results from the H4, and then use
those for a calibration (which would make it independent of the H4's
calibration). There have been some mentions about different numbers of
points, about reporting invalid values, etc.

It can, that is why I said that you should store the uncalibrated state
in slot 0. Number of points, BW etc will be set via the serial commands
from the Saver side.

Does anyone KNOW, not guess, what the proper procedure to calibrate this
system using nanovna-saver is? Nanovna-saver is what it is, I'm not
bashing it or trying to change it -- I'm just trying to understand the
limitations and requirements to get good results out of the software. The
ability to store calibrations, write s-parameter files, and plot using
different formats is invaluable to me. I *really* want to use it for these
features, but not if I can't be sure of the measurement.

It really isn't that complicated, it becomes pretty obvious when you
examine the NanoVNA serial protocol documentation.

It depends on how different the results are. Remember, the FW interpolates

between measured and stored cal values. Saver can be configured with 1001
points so the cal. sampling is much finer than a cal. on the native NANOVNA
(without SAVER).

***

Saver can do unlimited (in theory) number of points. It will just do
the required points
in segments. For H4 that would be X times 401 points to get to your desired
number of points.
Word of warning: Saver is a Python single thread software, after a certain
number of points it becomes
time consuming to process more that ~5K points on a single CPU core.

Again, using SAVER, there is the option to use considerably more points for
calibratioin: Native is 401 points, SAVER allows up to 1001 points. So
extrapolation between measured points using the two calibrations will be
coarser with the native VNA cal than with the SAVER cal.

Just avoid extrapolation: use the same frequency span when measuring as you
did when you calibrated ...

Why not have a serious read of the information in the WiKi on this site?
There are several excellent guides there.

Dave - W?LEV

On Mon, Apr 28, 2025 at 11:55?PM Dragan Milivojevic via groups.io
<d.milivojevic@...> wrote:

On Mon, 28 Apr 2025 at 22:25, Dean W8ZF via groups.io <dwfred=
[email protected]> wrote:

Dragan,
This just confuses me again.

"Remove the calibration and save that to the default slot (0 slot) when
using NanoVNA Saver."

Remove *which* calibration? And save *what* to slot 0? Are you talking
about the H4 device? Do you mean from the calibrate menu, choose "Reset"
and then "Save" to memory 0?
What values does this put into memory 0? And since nanovna-saver depends
on the calibration of the H4 device, what is that calibration now (after
reset and store 0)?

Yes, memory 0 should store the uncalibrated state, essentially no

calibration. Saver takes whatever the device gives it, there is nothing in
the serial protocol commands that deal
with calibration data.

"When you calibrate the Nano (on device calibration) in the range as the
documentation suggests 0-900MHz with 401 points..."

Where is there an option on the H4 device to select the number of points
used for calibration? I haven't seen that as a menu option.

I believe that it takes the number of points set on the device. I never use
the device standalone so I don't remember which option it is.

If the calibration of nanovna-saver gives different results, depending on
the state of the H4's calibration, I don't know what to believe.

It's simple: NanoVNA has a simple serial protocol, you can set the
basic parameters, request the scan etc. If your on device calibration
is completely off you will get bad results without or with Saver
calibration since it's working with bad data from the start.

Forgive me, I still don't understand how this works together. I don't

see

why nanovna-saver can't just read raw results from the H4, and then use
those for a calibration (which would make it independent of the H4's
calibration). There have been some mentions about different numbers of
points, about reporting invalid values, etc.

It can, that is why I said that you should store the uncalibrated state
in slot 0. Number of points, BW etc will be set via the serial commands
from the Saver side.

Does anyone KNOW, not guess, what the proper procedure to calibrate this
system using nanovna-saver is? Nanovna-saver is what it is, I'm not
bashing it or trying to change it -- I'm just trying to understand the
limitations and requirements to get good results out of the software.

The

ability to store calibrations, write s-parameter files, and plot using
different formats is invaluable to me. I *really* want to use it for

these

features, but not if I can't be sure of the measurement.

It really isn't that complicated, it becomes pretty obvious when you
examine the NanoVNA serial protocol documentation.

--

*Dave - W?LEV*


--
Dave - W?LEV

Using nanaovna-saver, on a -f, I noticed that sometimes the circle on the Smith machine (on a simple capacitor, for example) could be larger than the grid circle.

Now, systematically, even before calibrating with nanaovna-saver, I perform a RESET on the case, which nanovna-saver doesn't seem to do (0.3.8 because W7). This RESET solves the problem.
--
F1AMM
Fran?ois

There is a hook/mouse click "box" in nanosaver to reset any previous cal.
Look for it and click it.

Dave - W?LEV

On Tue, Apr 29, 2025 at 5:02?AM Fran?ois via groups.io <18471=
[email protected]> wrote:

Using nanaovna-saver, on a -f, I noticed that sometimes the circle on the
Smith machine (on a simple capacitor, for example) could be larger than the
grid circle.

Now, systematically, even before calibrating with nanaovna-saver, I
perform a RESET on the case, which nanovna-saver doesn't seem to do (0.3.8
because W7). This RESET solves the problem.
--
F1AMM
Fran?ois

--

*Dave - W?LEV*


--
Dave - W?LEV