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You can take screenshots using nanoVNA app by just connecting to your nanoVNA and clicking the camera button.

Roger

HA!! Didn't know I could do that!!

Here at the pics. The green lines are moving.

Thanks!!

try to do your sweeps with some averaging (means more points/values per measure point are takern and interpolated) ... that make the curves more even

you even can do the calib with high avg .. and measure then with lower avg (on none at all)

are your connectors tight?? what cable do you use?? are those values jumping around if you move cables a bit (wiggle on them)???

that you have those waves at the lower end and straight lines on the rest of the scan is not normal

dg9bfc sigi

Am 30.08.2022 um 19:11 schrieb TE Dukes:

On Tue, Aug 30, 2022 at 11:50 AM, TE Dukes wrote:

Here at the pics. The green lines are moving.

I have a hunch it might be the harmonic mode that is having problems. Try calibrating from 50 kHz. to 200 MHz and see if it improves.

Roger

Here at the pics. The green lines are moving.

You have no trace information or markers displayed. See the orange box below to see what I mean.

If you did a software update you might need to do a Clear Config to flush out the old settings. It is under the expert settings and if you need a password it is 1234

Roger

Generator threshold value must be less then default 300M, need more detail see work in range 270 - 300M (reset calibration and see in this range)
From there threshold start problem.

After write it to CONFIG->EXPERT SETTING->THRESHOLD
After need save CONFIG->SAVE CONFIG

Here my generator:
As can see my device allow work up to ? 306M, but i leave default 300M
Your device can be near 290M (some device 280M)

Only had this for a few days. I don't know how to do any of what you suggested.
Connectors are tight. I didn't use cables with this calibration. I followed the guy in the video. I agree this does not look like the guy in the video outcome. he didn't have the lines extruding form the points.

Thanks!! But I'm not sure what you mean by generator threshold. Is that the stop point in the calibration?

Thanks for the info! Yes, I have calibrated in the App as well.

Not seeing my post after changing the range. I'll post the pics again.

That seems to correct the issue.

Thanks!!

I appreciate all the help with this!! I apologize that I don't know a lot of the terminology for this nanovna.

I'm still not certain if there is an issue with the nanovna itself. If you suspect one, then I probably need to return this unit.

Can anyone can recommend a brand/model that is known to be a good unit? I know this is a clone but even with clones, there are some better than others.

Again, thanks!!

As I understand it, he threshold setting changes where the internal generator switches from fundamental to harmonic mode or similar. The threshold you are setting will depend upon the capability of your devices's chip to oscillate beyond its specs; some will go above the default 300MHz and some only as high as 280MHz . The idea as I understand it is to reduce the threshold setting until you get a clean sweep on both sides of the threshold point.
73, Don N2VGU.

On Tue, Aug 30, 2022 at 12:59 PM, TE Dukes wrote:

Not seeing my post after changing the range. I'll post the pics again.

That seems to correct the issue.

OK it works at lower frequencies so we know the problem. It is what DiSlord described in his posts. The 5351 Clock chip used in the nanoVNA is only guaranteed to 200 MHz but it usually works up to 300 MHz. Some don't so the maximum frequency threshold is lowered in one of the menu options.

You change it here >> CONFIG->EXPERT SETTING->THRESHOLD
After you change it you do CONFIG->SAVE CONFIG

I suggest you try 280 MHz and then calibrate from 50 kHz to 900 MHz and see if you get the dots in the right place for short, open and load. If that works slowly increase from 280 (recalibrating each time) until it fails again and then back off by 2 or 3 MHz.

Roger

OK, I found what you were talking about. Mine was set to 300M and I changed to 280 as you suggested.

Will do another cal and see what happens.

Thanks!!

OK, I re calibrated at 280, it was worse. I went to 250, re-calibrated, worse yet. Went to 200 and re-calibrated even worse.

I think my nano is bad.

Hi.

It looks like you are having the dreaded Clock Generator instability around 300MHz. You can see the spurs around 300 and 600MHz on the yellow traces in your photos.
The basic design of the NanoVNA severely overclocks the 5351 Clock Gen chip which is only specced to 200MHz max.
Some chips just can't make it to 300MHz, especially the Chinese knockoffs.
Go into your configuration and look for something called THRESHOLD. It will be 300MHz at present.
Change this to 280MHz.
Clear all your existing calibration data and recalibrate.
This should fix your problem.
I have a Deepelec unit so I can't give you the exact menu steps for your unit.
There is a Menu Map available elsewhere on this group, just follow the path to the THRESHOLD item.

Good luck....Bob VK2ZRE

Got it working !!!

I had decided to send this back to Amazon and try another in case I may have gotten a bad one.

I flashed the 'original' Hugen FW back but must have used a newer version by mistake. Everything is working and I can do more than 101p.

Don't understand why one FW works and another doesn't. On Hugen's github, it mentions synchronizing with DiSlord FW. IDK but it is working!!

Thanks!!!!!!!

On Wed, Aug 31, 2022 at 05:40 AM, TE Dukes wrote:

Got it working !!!

I had decided to send this back to Amazon and try another in case I may have
gotten a bad one.

I flashed the 'original' Hugen FW back but must have used a newer version by
mistake. Everything is working and I can do more than 101p.

Glad you got it working. A few questions.

1. What Hugen version are you running now?
2. Did you use the NanoVNA-H4-MS or NanoVNA-H4-SI version? The SI version is for the original clock chip which is hard to get now. The MS version is for the Chinese clone clock chip which Hugen is using in recent production.
There is a label on the back of Hugen's H4 which has an M for the Chinese version clock chip.

Roger

Roger

Hi Roger,

Mine is marked HW version 4.3 MS on the back. I used NanoVNA-H4-MS_20220831.dfu from Hugen's github page.

Thought that was the version that was on it when I got it since the description on Amazon said updated 2022 version. Glad I installed the 'wrong' one, LOL!

Really appreciate your help!! Maybe if I had mention I had the MS version it would have been easier to fix the issue.

Thanks!!!!