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I set the sweep from 1 to 30mhz then do the cal save in pos 0 then restart it,in the smith plot the marker moves all the way to the left like it should with cho shorted but with it open the marker sits about 3/4 of an inch from thr right hand side not fully to the right,any idea why this is?,im using the cal kit that came with it.

Hi Paul
Have you tested you load for being 50 ohm. Mine went bust pretty quikly so try a different load
Kind regards
Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af paul larner
Sendt: 3. december 2019 08:58
Til: [email protected]
Emne: [nanovna-users] calibration skewed

I set the sweep from 1 to 30mhz then do the cal save in pos 0 then restart it,in the smith plot the marker moves all the way to the left like it should with cho shorted but with it open the marker sits about 3/4 of an inch from thr right hand side not fully to the right,any idea why this is?,im using the cal kit that came with it.

my load measures 49.8 ohm on my fluke.,forgot to say i did the cal on 3 ranges stored as 0, 1 and 2,. 0 was 1-30mhz,2 was 140=150 mhz,2 was 400-500 mhz range 0 is ok rage 1 is ok,range 2,ie 40-500 mhz is off!

Hello Paul
I had the same problem recently.

What you definitely need to do is resetting the existing Cal values in the memory before saving new data there.

In my -Q SW Version I even had to Reset the value and press SAVE to the intended Cal Location. Only with SAVE it got truly erased

After the next Calibration everything worked fine.

how do i do that?

In the vna menu tree there is a reset button/function.
That clears the cal values.

i did that already before i calibrated it,i get the feeling its to do with the range i have issues with is over the 300mhz fundamental frequency of the generator in the nano as on the lower frequencys its fine.

Paul,
If you want to ensure you clear out all old calibration data (as well as touchscreen and other data) connect the Nanovna to your PC and access the Console Command interface through a terminal.??

Then, use the CLEARCONFIG? 1234??? console command. (download and read the Console Command document from the files section.

Next, while in Console mode, calibrate the touchscreen using TOUCHCAL and then SAVECONFIG??

Reset the device and calibrate. This has fixed issues for many users.??

Regards,Larry

can you recomend a good terminal program to use?,im on win7/64bit.

I like TeraTerm but you can use the latest version of putty as well.






...Larry

RealTerm () is a very powerful free
terminal program for Windows.

ive done this,im trying to upload new firmware,i can talk to it with the terminal ok,but i cant seem to write to it using the dfu demo program,it sees the vna ok says its uploaded fine and set to verifie the upload but nothing is changed on the vna,in the tatget window in dfu demo if i click on the entrys there it gives all the available sectors but in the info section has a cross in every box,sort of telling me i cant write to any memory locations,ive tried it with a jumper wire and without,also tried using win 7 and xp,i want to load the firmware with bigger fonts!,im pulling my hear out,i just cant seem to write data to it,whats going on,am i missing something or is my vna duff?

now after clearing all the cal data and doing more cals in pos0 pos1 and pos2,ie hf vhf and uhf in the respective save positions,with ch0 open it reads on recall pos0 reads 2000-1 swr,on pos 1 open reads 2.1-1 swr and on pos 2 reads 2.07-1,any ideas whats wrong with this fooking pile of poo?

i found the issue,bad cal routine,ive updated the wiki,was someting the guides didnt mention/make clear!,its now spot on on all 3 ranges!

Paul,
You only read the brief procedure but not the whole calibration procedure. The <RESET> before calibration clears things out and doing a save a this point is rather pointless. The proper save comes after the whole calibration is complete at which point you have the choice to save to locations 0, 1, 2, 3, or 4. If you don't do a save at this point then the calibration will not stick.

If you don't do a reset before starting the calibration then when you perform a save at the end you will retain data from the previous calibration. That sounds like the situation you were experiencing.

This is the procedure from the developer and that is in all the operating manuals. It works for everyone else.

-Herb

its my understanding you reset then save to whatever slot you chose,then do your calibration and resave it in the same slot,doing it as you say gives me rubbish results!

On Tue, Dec 3, 2019 at 04:10 PM, Larry Rothman wrote:

Next, while in Console mode, calibrate the touchscreen using TOUCHCAL and then
SAVECONFIG

Larry, you forgot to mention that there is needs power off and power on just after clearconfig command.
If you use any kind of save command with no power off, it will leads to restore old bad config.

clearconfig command clears flash memory with configuration, but not RAM. The old config remains in the RAM and if you make save it will be stored back into flash. When you power off NanoVNA after clearconfig, and then power on. The firmware will see at boot time that there is no config in the flash and default config will be loaded.

On Wed, Dec 4, 2019 at 09:06 AM, paul larner wrote:

its my understanding you reset then save to whatever slot you chose,then do
your calibration and resave it in the same slot,doing it as you say gives me
rubbish results!

There is no needs to save after CAL RESET. You can perform calibration with no save at all and use it until reboot.

For new users, I recommend that you use the search key, short sentences or key words written there before asking a question.
Here's an example of a user on the same topic because he couldn't solve something: he opened five topics in a row and asked the question five times with a small modification. OK, I understand that anyone who does not know the solution cannot ask well.
Because only those who know the solution know the right questions.
But you shouldn't split TOPICS like that.
It is true that the WIKI and FILES folders are large, but they are linked thematically, but they are also large and multi-layered.
Thank you for your attention.

73, Gyula HA3HZ

Hi Paul -

ive updated the wiki

I have calibrated after installing NanoVNA-Q many times,
and SAVE->SAVE [0-3] is NOT required after CAL->RESET

RF CALIBRATE can fail for several reasons, but that is not one.
Here are some calibration failures that I personally experience:

1) Immediately after firmware installation,
failure to (by terminal command) `clearconfig 1234` followed by power off/on

2) After `clearconfig 1234` followed by power off/on, failure to `touchcal` and `touchtest`
If touch calibration is off, based on your personal touch style,
then it is too easy for one or more of the OPEN/SHORT/LOAD/ISOLATION/THRU/DONE
presses to NOT be detected. When press is detected, the next button highlights...
Watch for that, retry if not sure.

3) Failure to verify e.g. Smith plot change for each termination change during calibration
- may not get SHORT, LOAD or THRU termination properly connected

4) Connector crimp to coax failure
- I am always calibrating with RG-316 leads, and 2 have failed since July
- Crimp failure may be detected by LOGMAG or other plot change by touching connector
or by SHORT not registering correctly on Smith plot

I do many successful RF calibrations without saving, but still fail 1 of 4 or so, with or without saving.