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Interesting discussion…. Me thinks the calibration procedure/protocols/software for BOTH the unit, and software (saver) need to be fixed/made more user friendly. Especially for non-tech users like myself that do not understand much of this stuff and just want basic results after following easy instructions without taking an EE course on it!

I had thought when you did a cal reset in saver, it did a hardware cal reset (as if you did it on the Nanak nagar)? I guess that is not true…. A perfect example of why this cal stuff needs cleaned up a bit. Before all you smart guys jump on me for saying this, and state “if you read the documentation….”, I did read all the docs, as well as many of these threads. And, it gets very confusing for novice users like myself, and VERY easy to miss a simple hidden message about resetting the unit first, or doing a larger span cal on it prior to doing the software cal….

If I hit “reset” on something, it’s customary to assume everything is “RESET” and your starting from scratch. Now in this thread I find that is not the case…. A few simple checks in the software could solve many of these calibration issues/questions. For example, if you cal for a span 7.0 to 8.0Mhz, and then try scanning 7.5 to 8.5Mhz, it should NOT let you! You should get a message to the effect “The scan is out of cal. range”! If saver then calibrates on top of calibration data already on the unit, it should should check for this and tell you “Unit using calibrated data, are you sure…..?”

I know, your going to say you should check all this yourself…. BUT I should also check if my car has enough oil in it prior to every trip down the road too, but I don’t. And thankfully, since around 1930, there has been a red light on the dash to tell me if the oil is low! NanoVNA firmware and it’s app’s like Saver, should add the “red light” for us!! That is my 6 cents on the subject.

--
Regards,
Chris K2STP

I've had mixed luck with depending on the fit of the cover.

I can't find the one that was similar to that but included a cover. I ended up trimming off the storage compartment in my slicer, and it works much better.

73, Willie N1JBJ

Mine came from thingiverse. I love it.

It is perfectly clear now.

I firstly had made the calibration on the NanoVna and saved that in slot 0.

Then connected the NanoVna (by pressing the "Connecting to device").
Selected the wanted segments (let say 10) and frequency range.
Opened the calibration menu.
Pressed Reset in this menu (it does not reset the calibration in the device).
The cal components show Uncalibrated".
After the calibration the Cal Thru is perfect 0 db.
And that is what I expected.

Coming back on your remark " This was made clear by the the original author, Rune, in a post when he first released NanoVNA Saver.",? I had read the warning in BOLD? in Rune his opening window when you start with the calibration in NanoVna Saver.
So basically I was warned.....
Issue solved.

Kees

Op 4-10-2021 om 02:30 schreef Roger Need via groups.io:

Several cases on thingiverse.com

On 10/3/21 7:26 PM, Roger Need via groups.io wrote:

Jim,

Here is what Rune had to say about this in previous posts....

From his github -
"Before using NanoVNA-Saver, please ensure that the device itself is in a reasonable calibration state. A calibration of both ports across the entire frequency span, saved to save slot 0, is sufficient. If the NanoVNA is completely uncalibrated, its readings may be outside the range accepted by the application."

Other comments from this thread... /g/nanovna-users/topic/47415385#6642

"My personal preference is to have Cal 0 be full span, and then
making a calibration within NanoVNA-Saver, using the calibration assistant,
with the "Segments" count set to perhaps 10 or even 20 - which gives you
1010 or 2020 data points for the calibration. This calibration can be full
span, or for the range you are interested in. You can then save this, or
any other calibration you make, as files which you can name more
intuitively than "cal 0", "cal 1" etc. ;-)

It's worth noting, that any calibration in NanoVNA-Saver is in reference to
the particular calibration done on the NanoVNA: So if you re-calibrate your
NanoVNA, your NanoVNA-Saver calibration ceases to be valid, and may give
incorrect readings."


Roger

Exactly.. I'd go for "no cal" on the nano, and let -Saver deal with all of it.

I suppose in an uncal state it might go out of range (as Rune commented), but I've not seen that.

So maybe a good default is "cal over entire range" and store that as #0.

Do a search on Thingiverse for Nanovna - there are several designs to play with


On Sun., 3 Oct. 2021 at 9:11 p.m., KENT BRITAIN<WA5VJB@...> wrote: My first 3D printing project.Any suggestions for a the file to print a good case for the Nano??
Kent

Jim,

Here is what Rune had to say about this in previous posts....

From his github -
"Before using NanoVNA-Saver, please ensure that the device itself is in a reasonable calibration state. A calibration of both ports across the entire frequency span, saved to save slot 0, is sufficient. If the NanoVNA is completely uncalibrated, its readings may be outside the range accepted by the application."

Other comments from this thread... /g/nanovna-users/topic/47415385#6642

"My personal preference is to have Cal 0 be full span, and then
making a calibration within NanoVNA-Saver, using the calibration assistant,
with the "Segments" count set to perhaps 10 or even 20 - which gives you
1010 or 2020 data points for the calibration. This calibration can be full
span, or for the range you are interested in. You can then save this, or
any other calibration you make, as files which you can name more
intuitively than "cal 0", "cal 1" etc. ;-)

It's worth noting, that any calibration in NanoVNA-Saver is in reference to
the particular calibration done on the NanoVNA: So if you re-calibrate your
NanoVNA, your NanoVNA-Saver calibration ceases to be valid, and may give
incorrect readings."


Roger

My first 3D printing project.Any suggestions for a the file to print a good case for the Nano??
Kent

On 10/3/21 5:30 PM, Roger Need via groups.io wrote:

From what I understand you are resetting the cal in the NanoVNA before connecting to NanoVNA Saver. When calibrating with the Calibration Assistant in the PC program NanoVNA Saver you should already have the NanoVNA calibrated over a range larger than the range you want. This was made clear by the the original author, Rune, in a post when he first released NanoVNA Saver. You can search the group for his post.

I'm not so sure about that.? The interface (over the USB) doesn't expose any way to know whether the nanovna is sending calibrated or uncalibrated data to NanoVNA-saver. The data command with arguments 2,3,4,5,6 allow dumping the calibration coefficients in use, so maybe you could infer whether the results returned by data 0 or data 1 are calibrated or not.

Therefore, the key is that the nanovna is in a state that matches the state it was in when the cal was done with NanoVNA-saver. You could "stack" calibrations, for instance.

In general, though, the cal tables in the nanovna are for the 101 data points (on the base unit), with interpolation used for frequencies not in the table. NanoVNA-saver, though, can store calibration tables with arbitrary numbers of points (it's using scikit-rf's implementation of calibration)

I would argue, then, that you should "reset" (i.e. remove) the calibration on the NanoVNA (since that's a known state) before doing the cal on NanoVNA-saver.

From what I understand you are resetting the cal in the NanoVNA before connecting to NanoVNA Saver. When calibrating with the Calibration Assistant in the PC program NanoVNA Saver you should already have the NanoVNA calibrated over a range larger than the range you want. This was made clear by the the original author, Rune, in a post when he first released NanoVNA Saver. You can search the group for his post.

Roger

Some preliminary results.

Connected two NanoVNAs using Ts (so the impedance at the ports presented to the external device is ~25 ohms).

See setup2.jpg - You can see the interference when one nanovna happens to sweep across the receiver of the other. So I'd suggest setting up the software driving the two nanovnas to sweep one at a time. (sweep3.jpg shows what it looks like with one sweeping, the other set to a fixed frequency)

Cal works fairly straightforward, - pause the sweep on one unit, do the cal on the other. Then swap.? With a python script this will be easy.

Now for some results - I happened to have a 10dB pad and a 21.4 MHz BPF to fool with.

10dB pad produces results about like you'd expect (10db.jpg) . Each VNA is set up for S11 (yellow) and S21 (blue trace).

So does the filter (filter1.jpg) .? Note the difference between the S11 looking into the filter with the other side of the filter open (filter2.jpg) and terminated (filter3.jpg).

Next step is to work out some code to systematize the cals and measurements. I'll probably just modify nanovna-saver, since it already uses scikit-rf, and that has the calibration algorithms built in.

After having done a 2-port BNC calibration from 100 kHz to 2 MHz with the Nano-H4 (version 0.5.0) then the CH1 LOG MAG =0.01...0.02 dB of the Cal Thru. Perfect!
When I connect the H4 to the PC and use Nano-Vna saver 0.39 then before I press Connect to Device I select the Cal menu on the H4 and press Reset.
Then I press Connect to device and select my frequencies (100 kHz to 2 MHz) with 1 or 4 segments.
In Sweep settings menu the Attenuator in port CH1 (s21) in dB = 0.
Then I press Calibration and press RESET. Calibration components show all UNCALIBRATED.
I am using the Calibration Assistant.
At the end of the calibration I press Apply. As a result the s21 curve of the Cal Thru is a horizontal line with a possitive value of 0.15 dB.
I repeat the calibration on the H4 and again the result of the Cal Thru is CH1 LOG MAG =0.01...0.02 dB.
After repeating the Calibration with Nano-VNA saver the result is the same as the first time a horizontal line with a possitive value of 0.15 dB.
Is 0.15 dB as a result for a (not removed) Cal thru a usual value or has it also to be 0.01...0.02 dB?
I had expected 0.01...0.02 dB in both cases.

Any idea?

Kees

On Sun, Oct 3, 2021 at 04:52 PM, Foxy Fox wrote:

Many of the motherboards of the televisions made by Vestel have such a
joystick. Definitely find one at TV repair shops.

Thank you but I fear, in the UK, finding a TV traditional repair shop will be harder than finding a switch ;-)

73
Brian

On Sun, Oct 3, 2021 at 03:50 PM, Jim Shorney wrote:

Here you go:



So cheap I bought an extra as a spare.

73

-Jim
NU0C

Thank you.

I've EMailed a friend in the US and asked him to buy a couple and pop them in the post- I will send the money via paypal, that will reduce the shipping!

Paying DHL etc $16 seems crazy ;-)

73
Brian
G8OSN

On Sun, Oct 3, 2021 at 07:39 AM, Brian Reay wrote:

The joggle switch was broken off. Initially, I hoped it would be possible to
reuse it but there the damage to the switch is worse than I initially thought
.
Thanks to another amateur, I was pointed here where I found evidence they are
available but no ready sources.

Can anyone recommend a source please? Ideally in the Uk but if overseas, so be
it.

Here is an overseas source for a direct replacement. Cost is less than a dollar and 2 week shipping is reasonable... FedEx or DHL if you need it real quick but costs a lot more.



Roger

Many of the motherboards of the televisions made by Vestel have such a joystick. Definitely find one at TV repair shops.

Here you go:



So cheap I bought an extra as a spare.

73

-Jim
NU0C


On Sun, 03 Oct 2021 07:39:44 -0700
"Brian Reay via groups.io" <g8osn@...> wrote:

I’m trying to repair a damaged NanoVNA for a family member.

The joggle switch was broken off. Initially, I hoped it would be possible to reuse it but there the damage to the switch is worse than I initially thought .

Thanks to another amateur, I was pointed here where I found evidence they are available but no ready sources.

Can anyone recommend a source please? Ideally in the Uk but if overseas, so be it.

It seems a shame to scrap the beast for want of a switch. I appreciate it can be operated via a PC etc but the owner likes to use it hand held as he experiments with antennas etc.

Thank you in advance & 73

Brian
G8OSN

I’m trying to repair a damaged NanoVNA for a family member.

The joggle switch was broken off. Initially, I hoped it would be possible to reuse it but there the damage to the switch is worse than I initially thought .

Thanks to another amateur, I was pointed here where I found evidence they are available but no ready sources.

Can anyone recommend a source please? Ideally in the Uk but if overseas, so be it.

It seems a shame to scrap the beast for want of a switch. I appreciate it can be operated via a PC etc but the owner likes to use it hand held as he experiments with antennas etc.

Thank you in advance & 73

Brian
G8OSN

I have ordered two batches of boards from JLCPCB for the QEX September/October 2021 “Miniature SMA Step Attenuator” pp 9-21 by Tom Alldred VA7TA. There is a quantity of excess PCBs available. I do not anticipate that I will place another order, but I will continue to accept orders until my supply is gone.

More information is available on my web page

I expect to receive the second set boards near the end of October. The first board orders will be mailed next week about October 5, 2021.

Dick K9IVB