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I'm using the latest version installed a few days ago.
Perry

On Tue, May 31, 2022 at 2:26 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Tue, May 31, 2022 at 06:33 AM, Jean-Marie Polard wrote:

I have a problem with the NanoVNA-H(4) and NanoVNA-App

I can connect it on com5 but it does not read the data and mention
always a number of points error

Does someone has a trick to solve this problem ?

What version of H4 firmware are you using?

The NanoVNA app uses a binary protocol to transfer sweep data. This is
different than the old ASCII protocol that was initially used by the
NanoVNA. If your firmware is over a year old you need to update it.

Roger

Zack.

A few days ago, I was able to get the unit into DFU mode and it was
recognized in Device Manager. I installed the latest Firmware and was still
getting a white screen. At the suggestion of another post, I left the
analyzer off for a few days with the battery disconnected. I powered it
back up today with the results that it now shows in Device Manager and I
was just able to run a calibration through NanoVNA Saver but the screen is
still white.
Perry

On Tue, May 31, 2022 at 4:24 PM Clyde Lambert <clyde.lambert@...>
wrote:

Hello,
Being a past bata tester of FW for this unit, I have dealt with your
problem.
The way I cured it is as follows:
First shut down the NanoVNA.
Remove the back cover.
Using small tweezers or what you ha e short the boot pad to the vcc pad
next to it. While keeping the short, turn on the NanoVNA.
Remove the short, shut the NanoVNA off. Replace the back cover.
Now turn the unit on.
You should be able to re install the new, or old, FW by putting your
NanoVNA in DFU mode via the menu,
I have had to do this several times so, I installed a micro switch to
short the two pins without having to take the unit apart.
Clyde KC7BJE

Then turn the

Hello Roger,

Op di 31 mei 2022 om 19:40 schreef Roger Need via groups.io <sailtamarack=
[email protected]>:

The intent of my post was to reply to comments by Victor Reijs and G3TXQ
(sk) that the S11 mode was not suitable for measuring high impedances.
When it comes to the NanoVNA this is not true and actual measurements like
the one I posted can be used to prove my point.

It is not me but

or

who derives the accuracy.
Can you provide where they go wrong? That would be very helpful. For me.
Thanks.

All the best,

Victor

Roger,
It now shows in Device Manager. The screen is still while but I can connect
with Nanovna Saver and calibrate using the Calibration Assistant. Do you
think it's usable when connected to the computer to analyze an antenna? I
may need to use it with NanoVNA App on my laptop. NanoVNA Saver won't
install on the laptop due to a Windows dll error.
Perry

On Tue, May 31, 2022 at 4:04 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Tue, May 31, 2022 at 06:44 AM, Perry Westberry wrote:

Tried this and still just a white screen. I guess it's bricked. Thanks

for all

the responses.
Perry

You posted that you cannot see it in Device Manager. Can you see it in
DFU mode? This will require opening it and shortening 2 pins.

Roger

The measure feature works well...from the user manual

1.2.5 MEASURE
3. CABLE S11
Choose a frequency range such that the cable length is ~1/4 of the wavelength in the middle of the range. This
feature uses velocity of propagation. It automatically measures the length, characteristic impedance, and loss at the
point of the active marker. Choose the range so that the Smith trace crosses near R=0 between 亇j. The shorter the
cable, the higher the frequency range needed for analysis. Example: Assuming the signal must go out and back on a
10 m length of coax, multiply c * VoP and divide by 4X the coax length. (3e8 m/s * 0.67) / 40m ~= 5 MHz. A range of
5乚15 MHz would cover this.

On Tue, May 31, 2022 at 01:26 PM, AG6CX wrote:

I wonder if you鈥檝e had the same experience with the VNWA as with the nanoVNA
in this regard? Do you find the S11 measurements are accurate (enough) for
higher impedances (presumably >50 ohms) ?

I do not own a VNWA so I have no first hand knowledge to share. From what I have read it has better specifications than a NanoVNA. You could join the VNWA group and pose your question there... /g/VNWA/topics

Roger

Hi Roger:

Thanks for your comments and focus on dispelling the notion that S11 with nanoVNA might be inappropriate for high(er) impedance measuring.

Re:

鈥淭he intent of my post was to reply to comments by Victor Reijs and G3TXQ (sk) that the S11 mode was not suitable for measuring high impedances. When it comes to the NanoVNA this is not true and actual measurements like the one I posted can be used to prove my point.鈥�

I wonder if you鈥檝e had the same experience with the VNWA as with the nanoVNA in this regard? Do you find the S11 measurements are accurate (enough) for higher impedances (presumably >50 ohms) ?

I appreciate your recent comments and look forward to more!

Ed McCann
AG6CX

Hello,
Being a past bata tester of FW for this unit, I have dealt with your problem.
The way I cured it is as follows:
First shut down the NanoVNA.
Remove the back cover.
Using small tweezers or what you ha e short the boot pad to the vcc pad next to it. While keeping the short, turn on the NanoVNA.
Remove the short, shut the NanoVNA off. Replace the back cover.
Now turn the unit on.
You should be able to re install the new, or old, FW by putting your NanoVNA in DFU mode via the menu,
I have had to do this several times so, I installed a micro switch to short the two pins without having to take the unit apart.
Clyde KC7BJE

Then turn the

To Roger:

Thanks for your comments.

Consistent with the physics involved.

Ed McCann
AG6CX

On Tue, May 31, 2022 at 06:44 AM, Perry Westberry wrote:

Tried this and still just a white screen. I guess it's bricked. Thanks for all
the responses.
Perry

You posted that you cannot see it in Device Manager. Can you see it in DFU mode? This will require opening it and shortening 2 pins.

Roger

Example:
Cable length measured in M1 point
Impedance on M2
More points in this range - better measure quality

On Tue, May 31, 2022 at 06:02 AM, igor-m wrote:

Hi, out of curiosity I've made a measurement of my nanovna H4 stock RG316
cable (of length 163mm end to end, incl connectors).
NanoVna App shows 158.4mm, while H4 (Measure->Cable) shows almost identical
picture as Dislord's one, but with Z0=9k and length 1.6meter (instead of
~Z0=50ohm as on his picture below.). Both measurements done with open end. H4
flashed with today's v1.2.

Set start frequency more low (cable impedance measured on half frequency from point then smith rotate on 180 degree)

Heck, it's confused with NanoVNA-H (4).
However, it can be read that it is a 2.8 "-H shipped with this firmware.
As Roger Need wrote, the firmware needs to be updated.
If you haven't already done so, read the descriptions on the forum Wiki or you can read it on my website.
Sorry I misled you in the previous post.

--
Gyula HA3HZ ( )

Where did you vind v. 1.2? I can't find that anywhere.

Zack W9SZ

On Tue, May 31, 2022 at 11:26 AM, Roger Need wrote:

On Tue, May 31, 2022 at 06:33 AM, Jean-Marie Polard wrote:

I have a problem with the NanoVNA-H(4) and NanoVNA-App

I can connect it on com5 but it does not read the data and mention
always a number of points error

Does someone has a trick to solve this problem ?

What version of H4 firmware are you using?

The NanoVNA app uses a binary protocol to transfer sweep data. This is
different than the old ASCII protocol that was initially used by the NanoVNA.
If your firmware is over a year old you need to update it.

Just took another look at your console output. Your firmware is over 2 years old so you need to update if you want to use the NanoVNA app

Roger

On Tue, May 31, 2022 at 06:33 AM, Jean-Marie Polard wrote:

I have a problem with the NanoVNA-H(4) and NanoVNA-App

I can connect it on com5 but it does not read the data and mention
always a number of points error

Does someone has a trick to solve this problem ?

What version of H4 firmware are you using?

The NanoVNA app uses a binary protocol to transfer sweep data. This is different than the old ASCII protocol that was initially used by the NanoVNA. If your firmware is over a year old you need to update it.

Roger

On Tue, May 31, 2022 at 07:54 AM, AG6CX wrote:

I鈥檝e always thought of the conventional antenna parameter measurement as the
antenna being in series, i.e., Z load = Zs = Rs + Xs

But could you expand a bit on situations in which you use the parallel model
in general, or specifically to the sketch you posted?

Ed,

Yes most antenna analysis is done using the serial R+/-jX form for impedance. However as Jim Lux points out in another post today ( /g/nanovna-users/message/28231 ) there are cases where the parallel form is useful in antenna measurements.

The intent of my post was to reply to comments by Victor Reijs and G3TXQ (sk) that the S11 mode was not suitable for measuring high impedances. When it comes to the NanoVNA this is not true and actual measurements like the one I posted can be used to prove my point.

Attached is a simplified resistor model showing that R, L and C are present in physical resistors. For low values of R the inductance is the predominate reactive factor but for high values of resistance the parallel capacitive reactance across the resistor needs to be considered. Attached are some plots taken with a test jig designed to measure 0805 components with a 1K resistor mounted in the fixture. Someone new to VNA measurements would look a the R+jX plot and see that the resistance measured looks close to 1000 ohms at very low frequencies (997 ohms) but measures 950 ohms at 250 MHz. The erroneous conclusion is that the 5% error is due to poor measurement capability. However this is not the case because the decrease in R is due to the effect of parallel capacitance. The parallel capacitance is small (less than a pF) but we can measure it and see the actual resistance of the 0805 SMD component by looking at the S11 data in parallel format. The attached plots show that measured R varies from 996 to 1008 ohms over the range of 10 kHz. to 280 MHz. which is quite impressive for a $100 instrument. The capacitance calculated from the parallel reactance X is 0.14 pF across the frequency range.

From the above (and my previous 3K resistor plot) the S11 reflection method has been shown to make reasonably accurate measurement of impedances up to several thousand ohms. That makes it useful for measuring devices like inductors, capacitors and common mode chokes. The other method which is usually suggested for high impedance measurement is the S11 series method. This method assumes 50 ohm CH0 (port 1) and CH1 (port 2) impedance. The NanoVNA varies from 50 ohms over its frequency range and this leads to errors in the measured data. Since the NanoVNA is a two port, one-way device it does not have 12 point error correction to compensate for the deviation from 50 ohms. Owen Duffy has posted several interesting articles on the S21 series method using the NanoVNA on his blog. Measurements are shown to illustrate his points.




My own measurements using the S21 serial method have shown that the quality of the test jig, measurement frequency span and complex impedance range have a significant effect on the accuracy of the results. I tend to use the S11 reflection method most of the time and for cross-checking S21 results.

Roger

Does nanoVNA-Saver work on your machine?
I can see that win7 sp1 is running. To run Saver, I need some things that I described in a pdf file. Link:
Since this was the program before, I didn鈥檛 test to see if the NanoVNA App needed the same.

--
Gyula HA3HZ ( )

When dealing with a single feedpoint, working with impedances (and a series formulation of R+Xj) is traditional - it maps well into VSWR, etc.

However, when working with multiple feedpoints, or coupled antennas, sometimes admittances work better. Most method of moments modeling tools (e.g. NEC) build an admittance matrix. So when you have an NT card in NEC, you specify the network parameters in Y parameters. And excitation is specified as voltages - that is, the goal in a NEC type model is to solve for I given Y and V. The currents in the segments are then what is used to compute the radiated and near fields. This is the inverse of an impedance formulation, which would solve for V, given Z and I.

Then, once you've solved the system, one can convert the admittances into Z (or S, for that matter).

Another case where parallel formulations are useful is when you're looking at a unmatched antenna like an AM car radio - The antenna is very short, very reactive and mostly a capacitance. It's feeding a system that is a high input R with a shunt C (stray capacitance and feedline C) - You can use a Thevenin model of the antenna as a Voltage source and a series Z, feeding the parallel combination of Ramp and Ccoax+Camp. This forms a voltage divider and forms the basis of sensitivity calculations. Here, the voltage would typically be the E field * length of antenna.