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Ah the mysteries of electronics!? I was bemoaning the demise of my unit while sitting at the desk.? Then I saw the blue light come on.? I thought I'd turn it on and now it's working normally.
I had already ordered some ICs so I will be ready if this happens again, but for now it has fixed itself.? I ran several tests and all is as it was before it stopped.
Bob

In the play store.

Where do I find the android app?

Oh...? And I have not tried the web app. This is on the Android app.
Mike
On Wed, Oct 30, 2019 at 8:21 PM, Larry Rothman<nlroth@...> wrote: You're welcome!
Unfortunately, there isn't a user guide for the web app just yet and it's best to play with it and try everything in sight. You can't break anything.?
... Larry



? On Wed, 30 Oct 2019 at 8:46 PM, Michael Dooley via Groups.Io<msdooley@...> wrote:? Larry,
Found it!? Thanks!? ?Now I can use the app on my Android phone to check swr in the yard.
No more lugging the laptop around.
?
Mike de N5BGZ
? On Wed, Oct 30, 2019 at 7:40 PM, Larry Rothman<nlroth@...> wrote:? Actually, the web app DOES have SWR if you know where to set it up...
Press the small + at the lower right corner and select CH0 and then SWR in the next pulldown.?
... Larry



? On Wed, 30 Oct 2019 at 7:08 PM, Michael Dooley via Groups.Io<msdooley@...> wrote:? I'm using the nanovna with the PC program to measure swr.? ?
On a whim I loaded the Android app to see if it would do the same, but it does not have an swr setting.? ?
Does the webapp do swr?? Or is there an Android app the does swr?

Thanks,Mike de N5BGZ

IS this the sort of thing you mean?



Some limits on frequency range though.

Martin, HS0ZED

You're welcome!
Unfortunately, there isn't a user guide for the web app just yet and it's best to play with it and try everything in sight. You can't break anything.?
... Larry



On Wed, 30 Oct 2019 at 8:46 PM, Michael Dooley via Groups.Io<msdooley@...> wrote: Larry,
Found it!? Thanks!? ?Now I can use the app on my Android phone to check swr in the yard.
No more lugging the laptop around.
?
Mike de N5BGZ
? On Wed, Oct 30, 2019 at 7:40 PM, Larry Rothman<nlroth@...> wrote:? Actually, the web app DOES have SWR if you know where to set it up...
Press the small + at the lower right corner and select CH0 and then SWR in the next pulldown.?
... Larry



? On Wed, 30 Oct 2019 at 7:08 PM, Michael Dooley via Groups.Io<msdooley@...> wrote:? I'm using the nanovna with the PC program to measure swr.? ?
On a whim I loaded the Android app to see if it would do the same, but it does not have an swr setting.? ?
Does the webapp do swr?? Or is there an Android app the does swr?

Thanks,Mike de N5BGZ

On Thu, Oct 31, 2019 at 02:01 AM, Rich NE1EE wrote:

So that's my story...I wonder if this could be just a short?

VBAT input of STM32F072 has 3.6 V maximum limit. At the same time Li-Ion cell has 4.2 ± 0.05 V.

As you can see, VBAT cannot handle direct connection due to high voltage.
There is needs voltage drop for at least 4.25 V - 3.6 V = 0.65 V.

So, if you install diode with voltage drop smaller than 0.65 V you are at risk to burn out your STM32 ;)

Just today I measured voltage of the battery on my NanoVNA and got actual voltage on a fully charged battery 4.1 V.
It needs voltage drop at least 4.1 - 3.6 V = 0.5 V.

So, I believe this is the reason why diode with 0.5 V voltage drop is introduced here :)

I filled up my email quota - mainly due to huge messages from one person. I
probably had a number of bounces over the last 6 hours or so. If anyone on
any group has blocked me, pease unblock me, as there should not be any
bouces

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892

Tel 01621-680100 / +44 1621-680100

Hi Erik
I did not see any picture.
I have just taken "my own medicine" and used the calibration kit data I released the other day. I did sweep from 50KHz to 900MHz for the new NanoVNA-H I just got. I attach images where I sweep the 20cm APC7 airline and the a 26cm UT-141A rigid cable with the 50KHz to 900 MHz calibration kit settings and then used the calibration kit setting for 50KHz to 500MHz but still sweep from 50KHz to 900MHz. I did not enter 50fF for open C0 but a delay as defined in the calibration kit data.
It is still an open issue on my side if the internal 50fF has any impact when using the NanoVNA-saver.
However the result are pretty good and the S11 "peaking" around 50MHz could be the load as being capacitive is compensated with a negative inductance but I doubt. As the NanoVNA, as I understand, has no internal 5/6 term error correction, the result must be said to be great. If a 50KHz to 500MHz calibration was made it would follow the optimum performance as shown for the S11 images.
I will do that later
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af erik@...
Sendt: 30. oktober 2019 20:16
Til: [email protected]
Emne: [nanovna-users] Success in automatic bridge and calibration error correction calculation #internals #calibration

After calibration with the correct calibration error parameters, a 1 meter cable connected to the reference plane with short and open at its other end, should give perfect circles spiraling inwards in the smith chart.
This however was NOT true for my nanoVNA Using Octave I tried to do a parameter search for the OpenC0,C1 and ShortL0,L1, OpenOffset, ShortOffset, LoadOffset and LoadL0,L1 that would provide the right calibration correction but that did not work. At least the parameter search failed to converge to realistic numbers and the residue was always considerable. Even when only using OpenC0 the residue was large and had way too much structure

So I added a small error model for the bridge with only a constant offset for the reference R, both real and imag)

The first picture shows the open en short errors for the 1 meter cable after calibration without any error correction or calibration model parameters.
The red and green lines are the abs of the deviation of the S11 versus a straight line from 50 to 300MHz The blue line is the abs sum of both errors.
The second picture shows the final modeling parameters and the residual error. the residue is now mostly noise. Only a OpenC0 of 52fF is needed to correct the calibration set to this level. The bridge correction is 0.29 - 0.6i ohm.
The third picture shows the S11 of a 1 meter cable with open end from 0.5 till 900MHz I have not yet found an error model that can model errors above 300MHz

Any suggestions?

Larry,
Found it!? Thanks!? ?Now I can use the app on my Android phone to check swr in the yard.
No more lugging the laptop around.
?
Mike de N5BGZ
On Wed, Oct 30, 2019 at 7:40 PM, Larry Rothman<nlroth@...> wrote: Actually, the web app DOES have SWR if you know where to set it up...
Press the small + at the lower right corner and select CH0 and then SWR in the next pulldown.?
... Larry



? On Wed, 30 Oct 2019 at 7:08 PM, Michael Dooley via Groups.Io<msdooley@...> wrote:? I'm using the nanovna with the PC program to measure swr.? ?
On a whim I loaded the Android app to see if it would do the same, but it does not have an swr setting.? ?
Does the webapp do swr?? Or is there an Android app the does swr?

Thanks,Mike de N5BGZ

Actually, the web app DOES have SWR if you know where to set it up...
Press the small + at the lower right corner and select CH0 and then SWR in the next pulldown.?
... Larry



On Wed, 30 Oct 2019 at 7:08 PM, Michael Dooley via Groups.Io<msdooley@...> wrote: I'm using the nanovna with the PC program to measure swr.? ?
On a whim I loaded the Android app to see if it would do the same, but it does not have an swr setting.? ?
Does the webapp do swr?? Or is there an Android app the does swr?

Thanks,Mike de N5BGZ

I have been following this discussion and wondering why the variety of diodes, including Schottky, are used by different folks. And I saw the comment in a post that the firmware assumes a 500 mV drop. I looked at schematics from edy55 and Hugen, and compared those to docs from ST. I hope that the upload shows in original detail, because there is a lot of fine print there. (Aside, as my earlier images show, there is plenty of room for a regular diode next to my battery mini-molex plug.)
edy55 shows D2 as an LED, but then shows a Schottky tied to VBAT.
Hugen shows a Schottky coming from the battery.
But all the ST manuals seem to show VBAT tied directly to the battery. In one ST image (see attached) what looks like a constant current source is tied to VBAT. The rest show VBAT tied to a battery or to VDD, and one shows PCB jumper pins to select either VDD or BATT to go to VBAT.
So that's my story...I wonder if this could be just a short? I don't have FULL schematics, and the down side to these fragmented schematics, which are somewhat less cluttered, is that they lack information...in this case, I don't know what the anode is tied to...but if it is BATT, then it seems that a diode is not useful here.
The usual apologies apply...you can see that I am speculating...I'd be happy to provide more images.
Oh, yeah, one ST design doc DID have a Zener or summat tied to VBAT, but it seemed that it was there to absorb spikes, such as you would get starting a car or summat.
--
On the banks of the Piscataqua
Rich NE1EE

On Wed, 30 Oct 2019 at 19:16, <erik@...> wrote:

After calibration with the correct calibration error parameters, a 1

meter cable connected to the reference plane with short and open at its
other end, should give perfect circles spiraling inwards in the smith chart.

This however was NOT true for my nanoVNA

So I added a small error model for the bridge with only a constant offset

for the reference R, both real and imag)

The bridge will have some imperfections, which will be frequency dependent,
so I don’t think it is sensible to try to attach an impedance to the bridge.

The coaxial cable will have loss which will rise with frequency. The fact
that the coax has loss means that it must have a complex impedance. A lossy
coax can’t have an impedance which is purely real.

I see a couple of issues

1) Your coax is going to be rather lossy.
2) The impedance of typical cables have a specification of +/- 2 ohms.

Only a OpenC0 of 52fF is needed to correct the calibration set to this
level. The bridge correction is 0.29 - 0.6i ohm.

Any suggestions?

Yes - I would give up with your length of RG58. A few improvements

1) Use a 3.5 mm to APC7 adapter with a proper APC7 airline. I bought a 20
cm APC7 airline for about $50 off of ebay. Not cheap, but probably the
best solution. A 3.5 mm airline would be better still, but I am unaware of
any long ones being available. I have a few, but they are too short for a
900 MHz instrument.

2) Use 1 m of RG401 semi rigid. That has a very low loss, so will have an
almost a real impedance, but it could be in the range 48-52 ohms.

3) Buy an SMA T-piece. That’s a 3 port network. Terminate one port is some
reasonable impedance - any old nominal 50 ohm load will do, but in theory
it can be any impedance. Then use the T-checker method:



This method assumes that the T-piece is lossless, which I think is a better
approximation than assuming a bit of RG58 is lossless. However, that
doesn’t mean that x dB of loss messes things up the same in each method.

*Is your intention to add proper support for calibration kits in the
NanoVNA FIRMWARE?* I would really like to see that. I would like to use N &
7-16 calibration kits, but those are impossible to do well without taking
into account their characteristics, as for example the delay on a male N
short or open can’t be made anywhere near zero.

*If that’s your intention,* drop me a private email and I will send you an
SMA calibration kit



free of charge *if you want one.* (My company produces VNA calibration
kits). The S-parameters of each standard is individually measured using an
HP VNA and HP calibration kit.

A verification attenuator is also supplied,



which means that you can actually measure something with known properties.
The calibration kit used to measure the attenuator is a 26.5 GHz 3.5 mm HP
85052B - *not* the calibration standards supplied. That essentially means
detects 99% of all possible errors.

* A damaged calibration standard
* incorrect entry of calibration data
* Errors m in the VNAs calibration algorithm
* Most hardware faults in the VNA

will all be detected.

Small discrepancies between your measurements of the attenuator and our
measurements of attenuator are to be expected. It will however be hard to
know if that’s due to minor problems in the calibration algorithms, or
hardware limitations of a $50 VNA.

Dave


--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

the funny thing is that this swap of bytes is not needed. And even if it needed for some reason it will be more easy to do on PC side. But it is works in such way, so we need just to live with that

As I read these comments, I wondered if edy55 was interfacing to a little endian machine, and to make life easier, swapped those bytes in firmware. It's a classic bit of trouble twixt swapped endian and non-swapped endian devices, and is especially a problem when more bytes are involved, such as 12345678 > 78563412, which just looks horrible. Easier to debug when they represent a number, but when it is padded RGB, it ain't intuitive. The ST reference manual states "The bytes are coded in memory in Little Endian format" so this may be at the root of this discussion. I don't know how other data is transferred twixt the ST and hosts, but this is a memory mapped transfer, and therefore not handled by an interpreter function, such as a C lib that handles integer transfers twixt endians.
--
On the banks of the Piscataqua
Rich NE1EE

I'm using the nanovna with the PC program to measure swr.? ?
On a whim I loaded the Android app to see if it would do the same, but it does not have an swr setting.? ?
Does the webapp do swr?? Or is there an Android app the does swr?

Thanks,Mike de N5BGZ

On Mon, Oct 28, 2019 at 02:11 AM, Oristo wrote:

Perhaps nanoVNA display has some unintuitive color matching;

all is intuitive, just edy555 reversed bytes in the pixel on firmware side. This is why data returned from NanoVNA to PC is different than data returned from display to NanoVNA. Just reverse bytes in each pixel and it will be the same as original data from display :)

Thanks Rune,
it works now ... I had not tried to go further and give the command "python3 nanovna-saver.py"

now we need a system of self-adaptation to the resolution of the screen, netbook PCs have a resolution of 1024x600

73 of IK0OZB op.Luigi

I guess that 'sample' works with 'scan' and 'data' commands

How does scan work?
Can it return multiple calibrated CH1 values for a single frequency?

By reading code, I now appreciate that
'sample' affects both 'sweep' and 'scanraw' for all traces.
Have yet to sort what 'port' affects; should not affect all traces..??

Despite requesting 10 points, 101 are returned by `data`,
but frequencies works..

ch pause
ch scan
usage: scan {start(Hz)} {stop(Hz)} [points]
ch scan 10000 11000 100
ch data | wc
101 202 2740
frequencies | wc
10 10 70

I think horizontal line from cable loss.

Very good free simulator program:



Simulate lossy coax (for example RG-58), now subract with ideal lossless coax. Negative coax lenght supported. Now near horizontal line, not dot the zero and infinity impedance on smith chart.

I already requested not only electrical lenght compensation, loss compensation important too. With firmware mod or/and external program.

Best coax is a precision air line, very expensive.