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I am a new owner of an Aursinc NanoVNA-H, HW Version 3.6
Charged it for 4 hours out of the box, but only RED LED solid.
Used it for 90 minutes matching mobile HF antenna; seems to work fine.
Now to charge it after use. Still getting only RED LED solid. (?)
Not sure about this indication or if it is charging.
Any ideas?

On Fri, Mar 4, 2022 at 03:34 PM, Colin McDonald wrote:

It's a specific tool. One must use that tool as intended or it is no longer
useful.

I think we all agree with that :). My question is how to make it more useful (or easier to use) without breaking the bank. I hope the answer is to have a feature request for one of future releases that will "hardcode" SOL at S11 port, so I get Slot 0 back for other use :) I see that as a perfectly realistic request, if (IF!) there are no known variations between individual devices when it comes to SOL at S11.

Based on my very limited knowledge of this technology, calibration does "only" two things - accounts for t-line losses, and compensates for the effect of the t-line electrical length ("unrotates the complex impedance vector"). If I'm willing to accept lack of compensation for losses in the t-line, and also only need S11[dB]/SWR, and don't "care" about accurate (or even indicative) values of complex Z. If differences between individual nano's are minimal, and that does not significantly drives the need for calibration, I'd really like to have a single button somewhere in the menu saying "click here to SOL at S11" :)

It takes seconds to perform a SOL calibration at the S11 port.

Not always true :) I sometimes need a quick measure when S11 port SOL is not an easy thing to do, and I forget to do it ahead of time :)

I've found the 3 measurements that hams need, SWR, Z impedance and capacitive
reactance to have very little variation between using a wide spectrum
calibration and a narrow calibration that is frequency specific.

I agree! The key problem I have is doing that calibration :) You are right, it's me, not the tool, but if that tool can make me better, or compensate for my shortcomings, why not :)

At HF frequencies, the coax is generally a factor in the antenna system so you
want to measure it along with the antenna for tuning purposes. You don't
necessarily want to calibrate each individual coax as you are trying to
calibrate a portion of the antenna itself at that point which doesn't give a
clear picture of what the radio is seeing at the shack end of the coax.

In general I do agree, but it's not that simple - sometimes I need SWR scan at the side of my RIG, sometimes I want to understand my antenna itself and then I'm willing to do proper calibration wherever needed.

For another thread - attaching a coaxial cable to my new antenna usually changes "everything" - complex Z, radiation pattern, ... That's why all my measurements at the antenna feed point have fairly good "balun" (current balun = CM suppression) that significantly limits the impact of the t-line to antenna "geometry". That's also why measuring at the RIG becomes necessity to understand (measure) potential impact of the t-line and to see what my TX is actually going to see

It is always a good idea to watch the behavior of the various calibration standard traces as you perform a calibration; you can spot an incorrect or damaged standard or poor connection just by the general shape of the trace.
73, Don N2VGU

It's a specific tool. One must use that tool as intended or it is no longer useful.

It takes seconds to perform a SOL calibration at the S11 port. Perform a wide spectrum SOL calibration and save that as a reference point. It'll be close enough for amateur radio antennas.

If you question the accuracy, again it takes a few seconds to perform a calibration at the frequencies you want.

I've found the 3 measurements that hams need, SWR, Z impedance and capacitive reactance to have very little variation between using a wide spectrum calibration and a narrow calibration that is frequency specific.

For instance, a SOL calibration right at the s11 port for 1.8 to 30MHZ shows very similar results to a SOL calibration at the S11 port done for say 14.13 to 14.35MHZ using the same antenna and coax to measure.

Any variation is as likely to be at the antenna as at the NanoVNA.

At HF frequencies, the coax is generally a factor in the antenna system so you want to measure it along with the antenna for tuning purposes. You don't necessarily want to calibrate each individual coax as you are trying to calibrate a portion of the antenna itself at that point which doesn't give a clear picture of what the radio is seeing at the shack end of the coax.


Regards

Colin

On 3/4/22 12:22 PM, Miro, N9LR via groups.io wrote:

On Fri, Mar 4, 2022 at 12:26 PM, Kenneth Hendrickson wrote:

calibrate at the end of the coax which will attach to the antenna

Easier said then done :)

* have limited number of calibration slots

If you're using PC software - it's a file.

* don't have an easy access to measure some of coaxials (previous installations, difficult to lower antenna, helping a friend, ...)

Definitely the problem.

* HAMs often change feeds on a whim and don't remember to recalibrate

Who me? Never do that. No way. :)

* ...
I have all kinds of calibration standards, that's not a problem, but "doing" calibration ahead of time (and being able to store it on nano) is often a challenge

On Fri, Mar 4, 2022 at 02:51 PM, Stan Dye wrote:

Once you do an SOL calibration at the nano pigtails, over your frequency
range of interest, save it to memory 0. The nano initializes to this when
you turn it on, so you don't need to repeat the SOL each time.

The point of Kenneth's (rightful) response was "calibrate each of your coaxial runs to antenna, recall that later. With more then 4 antennas that's not possible due to nano's limit to slots

On the other side, calibrating at the port is what I do, but I expect that can be done by a firmware/hardcoded value and recalled as needed. I use slot 0 for some other stuff sometimes :)

Once you do an SOL calibration at the nano pigtails, over your frequency
range of interest, save it to memory 0. The nano initializes to this when
you turn it on, so you don't need to repeat the SOL each time.

On Fri, Mar 4, 2022 at 12:23 PM Miro, N9LR via groups.io <m_kisacanin=
[email protected]> wrote:

On Fri, Mar 4, 2022 at 12:26 PM, Kenneth Hendrickson wrote:

calibrate at the end of the coax which will attach to the antenna

Easier said then done :)

* have limited number of calibration slots
* don't have an easy access to measure some of coaxials (previous
installations, difficult to lower antenna, helping a friend, ...)
* HAMs often change feeds on a whim and don't remember to recalibrate
* ...
I have all kinds of calibration standards, that's not a problem, but
"doing" calibration ahead of time (and being able to store it on nano) is
often a challenge

On Fri, Mar 4, 2022 at 12:26 PM, Kenneth Hendrickson wrote:

calibrate at the end of the coax which will attach to the antenna

Easier said then done :)

* have limited number of calibration slots
* don't have an easy access to measure some of coaxials (previous installations, difficult to lower antenna, helping a friend, ...)
* HAMs often change feeds on a whim and don't remember to recalibrate
* ...
I have all kinds of calibration standards, that's not a problem, but "doing" calibration ahead of time (and being able to store it on nano) is often a challenge

On Fri, Mar 4, 2022 at 11:02 AM, Jim Lux wrote:

The other plots are antennas measured using the cable calibration and not.

This VERY interesting - difference between measurements with calibrated vs non calibrated varies from just a fraction (1 or 2 db) to sigificant (10db and more).

If I understand correctly, your "calibrated" values are for SOL done at the port, or short length of coaxial cable connected for measurements, right?

My primary interest is HF (up to 30MHz), and (as expected) differences are more under control at the lower ranges.

Would be cool to have a "zero calibration" built in, so I can have a an easy option to get to that "default" state and accept the unknown impact of the unknown length of a t-line from nano to antenna feed point

On 3/4/22 10:26 AM, Kenneth Hendrickson via groups.io wrote:

--- On Friday, March 4, 2022, 10:43:41 AM EST, Miro, N9LR via groups.io <m_kisacanin@...> wrote:

Very rarely we get a luxury to connect nano directly to antenna feed
point over t-line that can be used in calibration.

Get a set of female SO-238 Short, Open, Load calibration ends, and calibrate at the end of the coax which will attach to the antenna.

73,
Ken N8KH

Or a UHF to SMA adapter (the 1/2" isn't important) and use your existing SMA cal standards.

You can flash the Nano with an ST-Link interface.
I bought one for $3 from Aliexpress - works great:
Also avail on Amazon.

I had a similar issue as you're having but only after I had done some soldering on the board - a small ball of solder was stuck across the data lines at the USB connector.
Just follow the instructions for the driver here: /g/nanovna-users/topic/34550986

--- On Friday, March 4, 2022, 10:43:41 AM EST, Miro, N9LR via groups.io <m_kisacanin@...> wrote:

Very rarely we get a luxury to connect nano directly to antenna feed
point over t-line that can be used in calibration.

Get a set of female SO-238 Short, Open, Load calibration ends, and calibrate at the end of the coax which will attach to the antenna.

73,
Ken N8KH

No luck with a new USB cable, still showing up as "Unknown USB Device (Device Descriptor Request Failed" in device manager.

I'm wondering if the firmware can be flashed via serial somehow? I think I may have a USB-serial adapter somewhere.

I couldn't figure out how to load the STM driver into Zadig to install the driver, just the generic usb drivers in the dropdown.

Thanks, I will try a new USB cable and the Zadig app. I am mostly positive the correct drivers are installed, so maybe forcing the new drivers will help.

On 3/4/22 7:43 AM, Miro, N9LR via groups.io wrote:

In HAM world, one of key uses for nano is antenna tuning, or at least better understanding what my TX is going to see.

Very rarely we get a luxury to connect nano directly to antenna feed point over t-line that can be used in calibration. More often is that I have a random length of coax in place, and can only measure what is at that point. In those cases, it does not matter what I have as a pigtail from nana to antenna system.

With full appreciation of what that means (don't know cable losses, cable rotates complex impedance, only SWR reflects what's at the antenna side, ...), and given that a pigtail on nano side is also random selection from immediately available ones but it's length is much shorter then lambda, I need a quick way to calibrate nano with respect to nano's port

Now question - what happens when I "reset calibration" on nano - will that in effect be equivalent to calibrating nano directly at the port?

If not, what is the quickest way to get calibration that will get me going quickly, without the need for SOL?

You can do a SOL calibration at the NanoVNA (that takes out the basic instrument issues) - and then measure your antenna.? As you say, the coax will add a phase shift to the S11, and will show better match (more negative S11 magnitude, lower SWR).

cables.png is? two cables measured with the far end open.

The other plots are antennas measured using the cable calibration and not.


If you use some PC software, you can do a calibration of the coax, once, and save that. Then you can fire up the NanoVNA, tell the software to use the "with coax" calibration, and measure your antenna.

In HAM world, one of key uses for nano is antenna tuning, or at least better understanding what my TX is going to see.

Very rarely we get a luxury to connect nano directly to antenna feed point over t-line that can be used in calibration. More often is that I have a random length of coax in place, and can only measure what is at that point. In those cases, it does not matter what I have as a pigtail from nana to antenna system.

With full appreciation of what that means (don't know cable losses, cable rotates complex impedance, only SWR reflects what's at the antenna side, ...), and given that a pigtail on nano side is also random selection from immediately available ones but it's length is much shorter then lambda, I need a quick way to calibrate nano with respect to nano's port

Now question - what happens when I "reset calibration" on nano - will that in effect be equivalent to calibrating nano directly at the port?

If not, what is the quickest way to get calibration that will get me going quickly, without the need for SOL?

First off, Thanks to all that responded.

Further checking on #2 VNA gives the same results; Smith Chart showing a solid 50 Ohm load with No Inputs/Cables connected to S11, on HF / VHF / UHF frequencies, and Calibrated / Not Calibrated. #1 VNA shows a Open for all of the above.

So it would appear that it is possibly a dead receiver or at least some internal issue as was suggested so it's going to be sent back.

With the first two nanoVNA-H's I've done so many Calibrations that I simply stopped looking at the Smith Chart after completing the calibration. If I would have done that with this #2 VNA (looked at the Smith Chart) I would have see right off that something was indeed wrong internally. Sorry about that... Live & Learn!

tnx agn

73's
de George
WD0AKZ

dit - dit

Hi Ron,
Thank you for the tip. Someone also suggested same as you said. But there are few other things and until I do not go through them its not going to show the graph properly. I tried changing the scale from 0.25 to 2 with no success. Someone on another group also suggested extra few things. Will do and post the results here.

Sohail VE3ITU.

Hi Nick,
Thank you for your reply. I already gone through that user guide that you are referring to. As you see I mentioned in my post above but obviously missing some important steps. I got some suggestion from another group. Will post the findings.

Sohail VE3ITU.

On 3/2/22 10:21 PM, Colin McDonald wrote:

Odds are good that you either have a problem with the s11 SMA connector on the second #2 NanoVNA, or that your open and short calibration hats are dirty or somewhat defective.

Try at a few different frequencies to be sure.

Try VHF and UHF as well as other HF frequencies. If you get the same kind of results there is something wrong. Could be as simple as a bridge solder connection or a defective SMA port on the NanoVNA.

The interesting bit is that with the 50Ohm SMA load hat everything looks good on both units. But with the open and short hats #2 is giving strange readings especially for the Z impedance numbers.

A dead receiver on CH0 would show good load, and bad open/short, because in the load case, there's no reflected power.