How to tell if you have a bad NanoVNA

This was a fun journey/project to play with and I learned a lot. Let me share the journey with you and how you can tell if your Nano is good or not.
👉 The Trusted Source for NanoVNAs is R and L electronics in Ohio: bit.ly/3q3OHdN
👉 Firmware Update for NanoVNA-H: github.com/DiSlord/NanoVNA-D
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0:00 Intro
0:56 Touch Screen Problems
4:05 Sweep an Antenna
5:30 Comparing against a Good NanoVNA
7:20 Firmware Update #3
9:45 Switches to Center Mode?
10:38 Physical Comparison
13:24 Test Dummy Load on the K9WEN Unit
14:24 NanoVNA Test Procedure
19:00 Bad NanoVNA
22:33 Conclusion
23:19 Thanks for Being Awesome!

[@randyslaten299]

Don't know if this is the best place to rant about this, but here goes... Make sure to select DISPLAY->CHANNEL = "S11 (REFL)", not "S21 (THRU)", for measurements like SWR and SMITH charts made on PORT 1 (S11). For HF calibration, use 1 MHz -to- 30 MHz stimulus range: STIMULUS->START = 1 MHz, STIMULUS->STOP = 30 MHz. By all means use a smaller range for higher accuracy if necessary. Always reset calibration data before performing another one: CALIBRATE->RESET. Perform Open-Short-Load calibration and save result: CALIBRATE->OPEN..SHORT..LOAD..DONE->"SAVE 0". All settings and calibration data stored in "SAVE 0" will be loaded upon power-up. Verify good calibration by placing Open-Short-Load devices on PORT 1 and observe that "dot" position appears at right-left-center on SMITH chart center axis. If calibration was done right at the SMA connector on PORT 1 but an open coaxial jumper and/or adaptor is later added, the SMITH chart will show a rotated arc instead of a "dot". By introducing an electrical delay the calibration reference plane can be moved to the end of the jumper/adaptor to compensate. Automatically: MARKER->OPERATIONS->E-DELAY Manually: DISPLAY->SCALE->E-DELAY = "value" (+/- nS or pS) Re-save to include in location of choice, e.g. "SAVE 0", "SAVE 1", etc.

[@temporarilyoffline]

This is good info.

[@jeffreyfritz5866]

You have descirbed exactly the way that my NanoVNA is acting. It acts like your bad one. R&L is replacing it with a newer version. Your video and testing was immensely helpful! 73

[@temporarilyoffline]

Glad it helped!

[@MidlifeRenaissanceMan]

I picked up a used Nano VNA F that had some similar issues. Buttons were all out of whack, but calibration was fine. I replaced the lithium battery and now it works like a champion. Problem free. Try replacing the battery, or giving it a reliable supply

[@temporarilyoffline]

Very good idea!

[@TonyLing]

I've just tried unplugging the internal battery on mine and running off USB-C. No change observed.

[@barrykery1175]

My NanoVNA H4 is build time Jan 31 2021 Version 1.0.45 and I don't have any issues at all. I have a RIG Expert AA-230 Zoom, AA 650 and a SARK 110. All four give me pretty much the same readings. This is not the firmware version that came with mine. I bought mine from R&L Electronics thinking they did their research before they went out and bought junk. I also purchased the TInySA from them. The TinySA had a slight glitch on the display on 40 meters when I narrowed the span down to 10 khz. I updated the firmware and the little glitch went away. Your video was very interesting and glad you posted it. Barry, KU3X

[@temporarilyoffline]

Thanks Berry! I wish it was easier to spot the "fake"... but it could have also had an ESD or something... I'm holding on to it for fun.

[@n8mail76]

I've had mine for several years now. I've always made excuses for why it sucked. It works. But it makes you pay patience to get results

[@temporarilyoffline]

I have a second one that works well.I use it a lot and it is great.The one in this video just seems to be a fake.

[@Number4lead]

I bought a nano VNA on amazon. I have attempted to build several antennas from quagis to moxons to j poles. My vna always measured poor to mediocre performance. I always assumed I did something wrong, although I measured everything to a T. Now I'm wondering if my vna is faulty all this time. I'm going back to the good old reliable SWR meter.

[@temporarilyoffline]

I've been happy with the aursinc label on Amazon. You could try a second one for something to compare too and return it if it doesn't work as expected. The Nano has so much functionality (when it works), but the cloners have gotten ugly. Amazon link: amzn.to/3ezESBc

[@astrawally8448]

My biggest learning with these is that you need to be wary your own interactions and how they impact what you are measuring (capacitive coupling, induction effects etc), how well it is shielded (your Norcal looks hip but it is not shielded) and any grounding effects. The NanoVNA uses a few mW of power to make its measurements/sweeps, it doesn’t take a lot of interference to impact those. To show this, get your good NanoVNA and connect a known good VHF/UHF whip. Find best VSWR and start to interact with it. Point here is that there are so many factors at play that it is going to be difficult to blame the NanoVNA purely. I do agree with the other comments about battery and firmware updates but I don’t believe that any one supplier or manufacturer is intrinsically building dud hardware beyond the odd faulty units.

[@temporarilyoffline]

Thanks for commenting!

[@rilosvideos877]

I am missing the red thread in test test procedure - looks more like try and error. Its essential to have proper shielding in place (esp. for higher frequencies) and to have a proper calibration first. When i buy from ebay or ali how can i know what i get? You probably should omit the lowest price offerings ;-)

[@temporarilyoffline]

Good idea💡

[@xiaonguyen6693]

great video, love the adhd extras :)

[@temporarilyoffline]

Extras? That's all natural 😄😄😄

[@bertbronson8395]

I am curious as to why the curves werent flatter given the swr was set to 1.0/ division on both devices (later in the video) instead of the 250m/ division you had on your device at the beginning of the video. 1.0/ gives a full range of like 10 vs 250m/ a vertical range of 2. That may not affect the readings or results, but it is curious...

[@temporarilyoffline]

I don't remember changing that setting either...

[@bertbronson8395]

@@temporarilyoffline 1.0 is the default setting. The IMSA guy goes thru that on his 'intro to the nanovna' video - thats the only reason I know that - had no idea what SWR was used for at the time LOL.

[@ToNzHoLtZ]

My nano vna was glitching until I installed the new firmware, and it now seems to work okay, except for the fact it does not have a DTF option ..

[@temporarilyoffline]

I'll try that!

[@Randy-xs4wm]

I actually need to buy a NanoVNA and would appreciate your recommendation (link) for which one to buy. By the way, affiliate links are ok with me (because the price doesn't increase for me if I use a link you sponsor, AND I get to support your efforts as well)!

[@temporarilyoffline]

Thanks, there is a link for R and L electronics in the description

[@vidasvv]

How does it compare if u slap a 75 or 100 ohm load ? tnx 4 the upload! 73

[@temporarilyoffline]

I need to get a set of those and find out.

[@Screamingtut]

mine comes up with the Blue logo like your friend's NanoVNA. I cannot read the version because I did not have my reading glasses handy.

[@temporarilyoffline]

There are a lot of different versions of the firmware out there.

[@peterdekeles.]

Would love to see a video on updating the firmware

[@temporarilyoffline]

Its on the table. I found a really good firmware to install during this diagnostic process. I'm very impressed with how well it gets installed and the "polish" it puts on the device. It just seems like the creator thought about the interface a bit and rounded off the rough edges.

[@peterdekeles.]

@@temporarilyoffline I look forward to it. Thanks Steve

[@PhilLeith]

I have one a friend gave me ... and I am getting results I would not expect. SWRs in the 10:1 range in the range this dipole is cut for. I'm thinking maybe it's a bad one

[@temporarilyoffline]

I had to run a side by side comparison with another analyzer to prove it

[@tmiller9099]

Do you need to set the range/stimuls before calibration?

[@temporarilyoffline]

Yes, you should set it to what interests you in the testing you're doing. Gotta ask the right questions to get the right answers.

[@TonyLing]

Can it actually be counterfeit? I understand that it is an open source design. My H4 behaves in a similar way. The interface can be unresponsive, and the measurements are not consistent. I think I'm going to buy a V4.

[@temporarilyoffline]

Counterfeit in the sense that it was made and sold by somebody that didn't know what they were actually making.

[@DonzLockz]

what was the end result? Did you return it?

[@temporarilyoffline]

This one was a fake, it was also a channel donation and I've kept it hoping that I can fix it someday. I need to do a firmware update on it to use a 3rd party firmware and see if that helps among other things. If your a ham and you're bored... you're doing it wrong!

[@bryantwalley]

@@temporarilyoffline all the components in these are relatively cheap to begin with. I would be curious to know if it was truly a fake or if they (Chinese manufacturing) are just buying components in bulk and relying on the law of averages to produce good ones and just accepting that they may have to eat a few returns.

[@temporarilyoffline]

@@bryantwalley This is exactly how I feel about the MMDVM boards - we bought about a dozen of them from Aliexpress and half didn't work - requiring some surgery, etc. Finally I got tired of being QA and just ordered a complete unit from a known brand on amazon. I paid more, but I knew it would work when I got it... and it did.

[@jamescoleman4747]

Try and remember to ground the coax before connecting your vna or other kit.

[@temporarilyoffline]

That's a great idea!

[@ronalddang7507]

If you're using a regular stick antenna on an HT, do you need to ground it? If so, how?

[@temporarilyoffline]

Usually you are the ground in an HT. But you can add a "tiger tail" and get greater range. When you take the antenna off the HT to test, you need to replace that missing human factor.

[@ronalddang7507]

@@temporarilyoffline I see, so how would one replace that "human" factor? Sorry if these are simple questions, I'm quite new to electronics myself

[@temporarilyoffline]

​@@ronalddang7507 No problem with the simple questions, that's what I'm here for. That's the "tiger tail" I mentioned earlier. Check out this short from my buddy Hayden - Ham Radio DX channel:kzbin.infoccJHdmSE7D4 What are you trying to accomplish? testing the antenna on the nanovna?

You should set the stimulus, or change the band before calibration.

[@temporarilyoffline]

I go over that in the video.

[@bill-2018]

I also experienced having to press the screen several times. I think in my case the battery voltage was a bit too low as it seems better now I keep it topped up after every use no matter how short. G4GHB.

[@temporarilyoffline]

Thanks Bill! Looks like you've got a good answer.

[@Tommyr]

I just bought one on Amazon and can return it if it doesn't work right within 30 days. Need it for VHF/UHF antenna testing. I already have an AA-55 zoom for HF.

[@temporarilyoffline]

It's a great gadget at a great price

[@izzzzzz6]

it only goes to 1 Ghz i think. Better get a newer vs they go much higher in frequency.

[@Tommyr]

@@izzzzzz6 I don't need one that goes higher.

[@tomstrum6259]

Can't believe you opened up your buddies Vna & pulled shielding cans off !!

[@temporarilyoffline]

When it starts out broken, you've got nothing to lose! :-D

[@izzzzzz6]

lol

[@TonyLing]

The shielding cans thankfully are not soldered in place, and pop on and off very easily

[@djdommes9302]

How about scale setting ?

[@temporarilyoffline]

Wouldn't that have returned to "normal" after a factory reset?

[@prestonshute7243]

Had to send mine back to Amazon, it was doing lots of strange thing. The screen was not operating correctly, lots of retouches on back. Did not agree with either MFJ meters. So I did a screen cal and that made it even worst. So back it went and they gave me full refund to my account. That unit was about $105.00. I may try buying another 🤞 73 Wd4dda

[@temporarilyoffline]

I got a second one and it has been good to me. The fakes are a problem. Glad to hear you got your money back with no hassles.

[@dannelson8556]

By far the number one killer of nano VNAs is static discharge. hams unfamiliar with working with VNAs will foolishly connect their VNA to an outdoor antenna without a pad or without discharging any static on the center conductor and poof goes the front end of your VNA. If you did this in a laboratory with $100,000 VNA you get fired and sued for the cost of the repair. vector Network analyzers are generally considered laboratory grade equipment not field equipment so they almost never have protection against static discharge. It is expected that the user is properly trained in their operation and knows how to discharge any static charge before attempting to connect the DUT. So several mistakes I see in your video, one is you connected an external antenna to lab equipment without properly discharging any static buildup. two you connected lab equipment to an external antenna without an appropriate DC blocking pad You should always use a 3db DC blocking pad on the front end of your VNA. And of course one of the very first things to look for when experiencing erratic performance with microcontroller devices is input voltage. In other words you need to check your battery' voltage as low voltage or inability to supply the required current can cause erratic performance. As a ham radio operator I would expect you to already know this.

[@temporarilyoffline]

You give hams a bad name.

[@frequencywatchers]

I Have My NanoVna Working Good, But The First Thing I Did I Changed The Basttery So Now It Works 3 Times As Loonger On A Field :) Sorry For You problem, Maybe I Can Figure It Out If I Put My Mind To It, Sadly I Would Have To Have Your VNA To Figure TThe Problem Out, I Bet Its Easy One:)

[@temporarilyoffline]

I'm open to any suggestions!

[@frequencywatchers]

@@temporarilyoffline Well, You Can Send It To Me And I Can Try To Fix It And Send You Back The VNA, I Have Some Smart Heads Over Here To So I Will Not Be The Only One Figuring Out Your Problem And We Could Maake Videos About This Thing :) I Can Make A Video How I Figured Out The Problem And You Can Make A Video About How Its Changed And Whats Changed And What You Are Doing With It Now And All That Stuff :) Ofcorse You Will Be Allowed To Use My Footage In Your Video Aswell To Show What You Want To Show

[@temporarilyoffline]

Message me on the discord or via email

[@darylcheshire1618]

You can re-calibrate the touch screen.

[@temporarilyoffline]

You can see in the video that I did that.

[@ur5gqf]

Купи очки, там масштаб scale/div разный на графике swr. Видно же что одинаковые платы...

[@temporarilyoffline]

2-minute rule.

[@uzaiyaro]

Calibrate the touch screen if you're having problems with the touch.

[@temporarilyoffline]

I did that in the video.

[@uzaiyaro]

@@temporarilyoffline I must have skipped over that part, and I must have had good luck with mine for a moment because it started being touchy again (pardon the pun) after I wrote this comment. I’m trying a firmware update tonight and will see if that has any effect. It’s not my nano anyway, so this might just push me towards a non-clone if I can’t get it to cooperate.

[@izzzzzz6]

I just picked up a nano for €45 inc. delivery. Hoping it's a good one. It's white.

[@temporarilyoffline]

Me too! Good Luck!

[@user-uv4xe3cq2y]

Before jumping to conclusions, replace the battery with a fresh one. Tnx for the video.

[@temporarilyoffline]

Would that make a difference if it is plugged in?

[@rickeaston3228]

Why did you keep it? I would have sent it back when the screens would not come up right. Why? It could be a legit unit but broke or it's a crummy clone. Either way, you should have gotten rid of it. It also has a dim display. Not very bright.

[@temporarilyoffline]

I kept it because a friend sent it to me and one day I might learn of a way yo fix it.

[@richardblanchard2743]

You didn't say what scale you have in swr per division.

[@temporarilyoffline]

You're right

[@curtw8827]

I've learned that updating firmware sometimes results in a brick.

[@temporarilyoffline]

I don't know if this was upgraded before I got it.

[@daviddahlgren9603]

Is that a dent in the case ?

[@temporarilyoffline]

Naa, just the way the plastics are made.

[@dombernal1399]

Use a HB pencil as a stylus.

[@temporarilyoffline]

Good idea

[@KingLoopie1]

If you have time, or a friend that has a hot air reflow station... You might want to try reflowing that board and cleaning it before updating it again. 👍

[@temporarilyoffline]

Good idea! So much to do in this hobby!

[@KingLoopie1]

@@temporarilyoffline you ain't a lying there!

[@DirtyPlumbus]

About 10 minutes into dealing with this the 24oz hammer would have come out and put the VNA to bed. Lol

[@temporarilyoffline]

Sometimes you just have to know for sure...

[@DirtyPlumbus]

@@temporarilyoffline I get that, but after reloading firmware you have to start asking yourself if you're gonna replace components on it or if it's better to just spend $60 on a new one from a different seller. Made for an interesting video anyway.

[@temporarilyoffline]

I bought another one anyway. Needed a control for the test!

[@DirtyPlumbus]

@@temporarilyoffline you got me hoping the one I just ordered isn't junk. Lol Honestly didn't even cross my mind before the video. Atleast now I'll have an idea of what to look for. Thanks

[@temporarilyoffline]

@@DirtyPlumbus no problem, good luck!

[@bulldogloverlover5496]

Incredibly long and not very clear. It was so long I forgot exactly what we were comparing.

[@temporarilyoffline]

Good thing there are chapters on the video.

[@TonyLing]

It is nobodies fault but your own that you have a short little span of attention

[@A_scope]

its most likely the bms and a failing lipo

[@temporarilyoffline]

Interesting idea! Just not enough voltage to make it run well enough?

[@baconsledge]

Pretty much cannot conclude anything.

[@temporarilyoffline]

Might need to take some notes or ask some questions.

[@yavamaystudio8045]

I had Hughen version, ...Very bad, 🤯 freazing, send back for refund

[@temporarilyoffline]

Oh no!

[@MountainMan7.62x39]

Whats wrong with you. Whats wrong with you. Asked three times, whats wrong with you. Oops missed asking whats wrong with you. Oops missed asking whats wrong with you again. Oops missed asking whats wrong with you again for the third time. Opps, didn't need to ask whats wrong with you, intended to ask something else.

[@temporarilyoffline]

Show me on the wheel of feelings where...

[@BigDamGun]

Hey dude, set the stimulus first before cal and your problems will go away and you won't waste the viewer's time ...

[@temporarilyoffline]

I realize you don't have the staying power to get to the point in the video where do the exact thing you accuse me of missing... let me make it really easy for you: 14:26

[@stevetotaro3219]

Why am I half way through the video and have no clue how to tell if I have a bad NanoVNA?

[@temporarilyoffline]

Check the description for chapters

[@stevetotaro3219]

@@temporarilyoffline You could have made a 30 second video. Compare your suspect VNA against a known a good VNA.

[@temporarilyoffline]

Your right, I could have.

[@stevetotaro3219]

@@temporarilyoffline You HAM guys really love the sound of your own voices. Bunch of chatty Kathies

[@k94536]

@@temporarilyoffline nooooo the more info the better thank you k6rys

[@nortonics5745]

Next time please take your meds first.

[@temporarilyoffline]

You win!

[@domfilap8477]

Well that was a waste of 10 minutes.... told me nothing!

[@temporarilyoffline]

Some people's kids man

[@TonyLing]

Yes Dom, you could have been giving it the five fingered knuckle shuffle for 10 minutes instead