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Nano VNA




 
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Author Topic: Nano VNA  (Read 1157 times)
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W1ITT
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« on: July 31, 2019, 04:04:52 PM »

The NanoVNA is a real two-port vector analyzer.  For fifty bucks or less, they are a miracle.  I bought two on Ebay and two from Aliexpress, for myself and friends.  I've made my living for the past few decades mostly with HP/Agieent network analyzers, but also Rhode and Schwartz and others.  I started off with a GR916 bridge which I still have. These little shirt pocket rigs are quite capable and I don't feel terribly handicapped, even with the little 2.8 inch touch screen.  There is free software that will allow connecting to a laptop for a bigger display, but that would seem to negate the fun of having a Smith chart in your hand.
These Nanos do everything they say and come with an open/short/load calibration kit.  My only complaint is that they use SMA connectors, which is necessary to keep things in a credit-card sized format.  I bought some short SMA to Type N and to Type UHF cables to enable connection to things that I commonly use.  I would not recommend putting an adapter directly on the SMA connector and then hooking up half inch cable!  They only run about -10 db (minus 10 db) source power so I'm not sure how they would perform down the road from a large AM tower, but it's worth a try.  And this is the first inexpensive unit I have seen with two-port capabilities to do "through" measurements of filters etc. It will do multiple measurement formats, with traces in different colors.
https://www.aliexpress.com/item/33045381877.html?spm=a2g0s.9042311.0.0.75c14c4dalCaKeke   
Take your pick via Ebay or Aliexpress.  My last pair took 12 days to make the trip from the Aliexpress vendor.  I think it was a bit over 3 weeks with the Ebay guy I used..  The point is that these things are legit. 
de Norm W1ITT
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KK4YY
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Golí na vydumku khitra


« Reply #1 on: July 31, 2019, 04:21:53 PM »

Those short cables will also act as connector savers. Some cheap SMA connectors can't take very many matings without wearing the gold off the center pin. I use connector savers on my cheap HT's from China. This, after I quickly wore-out the antenna connector on one of them. It's best to mate to those connectors ONCE.


Don
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WA2SQQ
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« Reply #2 on: July 31, 2019, 06:52:14 PM »

Tried to see if there are any reviews. Everything on YouTube is in some other language. Some say good to 300 MHz, other say to 900 MHz. How is battery life?
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W1ITT
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« Reply #3 on: July 31, 2019, 08:30:35 PM »

Yes the how-tos and reviews on Youtube are all in some other language.  I did find one with subtitles in English there.  The battery is good for about 2 hours untethered, and it'll come back to full in another couple hours plugged into the USB on my laptop.  The red led on top blinks during charge then goes steady when the thin  lithium battery come up to full.
Much of the firmware is close to the original EU1KY analyzer which was only single port.  I have one of those as well, and it's a hum dinger too, but costs almost $250 by the time you get it home.
Searches on "nanovna" turn up some relevant info, but it's pretty intuitive once you get going.
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W1ITT
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« Reply #4 on: July 31, 2019, 08:39:57 PM »

And I should have answered -SQQ's question on frequency range.  They go to 900 mhz but do so on harmonics.  Dynamic range is reduced from about 70 db below 300 mhz to about 40 db above 300 mhz.  In a lab grade piece of gear that would be a problem, but for most hams in a non-lab environment we'll do just fine.
Norm
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WA2SQQ
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« Reply #5 on: August 01, 2019, 08:15:39 AM »

I think I may order one - thanks
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WA4WAX
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« Reply #6 on: August 01, 2019, 02:45:04 PM »

Hard to beat at that price!  I will pass this on to the MagLab crowd.

BTW, Skycraft Surplus in Winter Park, FL sells some of the nicest SMA(f) to BNC(f) connectors I have seen.  They do NOT work their way loose like the most common design.  I am not sure who makes them.  They are gold plated, and would be FB for this little VNA.
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W4AMV
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« Reply #7 on: August 01, 2019, 09:46:07 PM »

There is a pretty extensive users group. See:

https://groups.io/g/nanovna-users

I have posted a number of measurements including narrow band crystal and mechanical filters, helical and tubular filters up through 900 MHz. A 465 MHz helical filter which demonstrated better 80 dB noise floor on a big box VNA was duplicated on the nanoVNA. So at least to ~ 500 MHz it is quite good,  when taking care in calibration. However, at 900 MHz, while the hp VNA demonstrated still 80 dB rejection, the nanoVNA was at 40 dB. For the most part the unit meets their advertised specifications.

Keep in mind, there are two units out there.  While they are identical hardware, the firmware is different. There is a 2 trace or 2 track unit which is a ONE port (antenna analyzer) only and a 4 trace or 4 track which provides S11 and S21 measurements. The firmware is open source so a 2 track can be updated to 4 track. In addition some of the folks appear to be extending the coverage range to 1.3 GHz.

The unit comes with SOL standards and the calibration is straightforward. Again, see the users group for quite a few good details and discussions.

Alan
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MikeKE0ZUinkcmo
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« Reply #8 on: August 02, 2019, 07:33:07 AM »

...And HERE'S an English translation of documentation.
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Mike KE0ZU

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WBear2GCR
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« Reply #9 on: August 02, 2019, 11:27:18 AM »

I bought one.

Mine was selected from a vendor that supplied a battery. Not all do.

I turned it on - it made pretty pics on the screen.
I HAVE NO CLUE what to do next...!!!

Comes with no instructions.

Figured i'd tether it to a computer with a menu driven software app and maybe figure it out
that way. Not much time to mess with it though. How about zero?

Hoping I will be able to look at all sorts of nifty things  with it... like my ANT, maybe help align the
IF strips on some rigs, stuff like that, mechanical filters, etc...

                                  _-_-
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W1ITT
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« Reply #10 on: August 02, 2019, 12:56:21 PM »

Ursus -GCR...
Nothing comes with instructions any more.  But the "manual" referenced in the previous post will get you to where you need to be.  Those of us whose fingers are larger than the Asian fellows do well to get one of those little rubber tipped touch screen pointers when using the unit by itself.  It's better than hitting two "keys" at once.

For a fun table top exercise, set it to scan the two meter band, perhaps plus and minus 10 mhz and see how crappy your rubber duck HT antenna is.  See if it's even anywhere in our allocation.  Then grab it and see how much it detunes. Do this with the Smith Chart, then with an SWR plot and one with return loss to gain familiarization.  Then, with adapting cables, look at a low pass filter, or perhaps a quarter wave coaxial stub off a Tee as a two-port measurement.

By the way, a number of years ago when I was purchasing some Smith Charts for graphic impedance matching calculations I spoke with Philip Smith on the phone.  He still answered the phone at the company if one of the other employees didn't pick up !  I wonder what the old gent would have to say about this shirt pocket analyzer.

Norm W1ITT
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W4AMV
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« Reply #11 on: August 02, 2019, 12:56:55 PM »

They are actually easy to use. However, like any instrument there is a learning curve. So which unit did you get, 2 trace or 4 trace? White Gecko or the black unit? I wrote a cal sequence and one of the members of the user group I posted earlier is writing a cal sequence flow chart based on this sequence. As well,  a very nice menu flow chart. The menu flow chart is very handy as it will permit you to get a top level view of all the soft keys that you will need to access in order to use the instrument. The screen is touch view menu driven. Find yourself a nice plastic stylus. The English version of the manual is helpful, BUT it is TERSE. If you need help, feel free to post. I have used it as an antenna analyzer over the past few weeks and it works quite well. There is one main issue and you will note it once you go outside. The LCD is washed out! Place it in a black non reflective box with a view portal. Punch a hole in the side to pass a cable and clips to grab the antenna feed point. I dedicated one of the 5 storage registers to the HF band for antenna work; 1-30 MHz. GL.

73 Alan

 
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W4AMV
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« Reply #12 on: August 02, 2019, 01:09:15 PM »

I will ask for permission from the author of the menu flow chart to publish the pdf here.

I think you will find it quite helpful, as well, get a birds eye view of the instrument functionality.

Alan
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W1ITT
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« Reply #13 on: August 02, 2019, 01:30:16 PM »

Alan :  The ones I have got are the black ones.  I didn't get the white ones with the gecko simply because I disliked it when I was working in the tropics and one would fall off the ceiling on me while I was sleeping.
So is there a difference between the geckos and the black boxes?
Norm
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W4AMV
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« Reply #14 on: August 02, 2019, 02:40:07 PM »

 Smiley Very funny Norm!

No, there is no difference. They are the same hardware, but for some reason, the firmware as of now is defaulting to 2 track or antenna analyzer in the white unit. Also, that firmware has a larger pixel size, so it is a bit easier to read. The black units, again as of date, have been shipping with 4 trace or 4 track with a smaller pixel size. Readable, but with 4 traces can be confusing. Of course you can turn traces ON and OFF, see the pdf on menu structure.

Firmware is public domain and you can upload and change as you desire.

Alan
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W4AMV
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« Reply #15 on: August 02, 2019, 02:43:09 PM »

Here is the pdf for the menu structure. I think you will find this very useful for navigating this device. The author did an excellent job of capturing what this box does as of today. There is a calibration routine FLOW CHART in the works now. When complete I can post.

Alan

* nanoVNA Menu Structure v1.1.pdf (56.78 KB - downloaded 38 times.)
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WA2SQQ
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« Reply #16 on: August 02, 2019, 06:25:01 PM »

Just ordered one, this looks like a nice toy!
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KD6VXI
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« Reply #17 on: August 03, 2019, 10:39:39 AM »

Remember a few months when I was posting questions about calculating a resistor from db loss?  There was a thread on this forum about it.

I had bought a VNA then.  Not this unit, mine cost about a decade more.

But, you will find uses for it almost daily!

They are amazing little boxes.

You can also get a program (excel file actually) called ZPLOTS from AC6LA.  It uses the touchstone files the VNA control program creates to do some really amazing stuff.

I'm probably going to buy one of these as mine needs a pc to run.  Great for benchtop work, but lacking in going outside and working.  The workaround there is do the OSL calibration at the end of the coax needed. 

You can also test for dB loss over a coax span with the S21 measurement.  I found a 200 foot piece of 9913 that was unused for 15 years was garbage.  Really bummed me out, but yes, coass does degrade doing nothing but sitting in a spool.

After having mine for a year plus, I still don't know all it can do.  But if any e has any questions, lemme know and I'll answer what I can.


My question about this unit....?  Is the case 360 degrees of coverage?  Looks like the sides are unprotected.

--Shane
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W4AMV
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« Reply #18 on: August 03, 2019, 11:32:14 AM »

Hi Shane.

Correct, the sides are unprotected. However, I have a colleague neighbor who is now printing a beautiful case that totally protects the unit. Very nice. I will shoot a picture and post. I can post his email address as well and you can contact him directly.

He is also researching and testing a LCD filter for the display. If you do outside work with the unit on a bright day, the display is washed out. Rig Expert and other antenna analyzers for out door work, did their homework on the application. More appropriate display for outdoor work. Another approach, place the unit in non reflective black box with a view port.

Alan W4AMV
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W4AMV
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« Reply #19 on: August 03, 2019, 11:45:16 AM »

Here is an enclosed case for the unit.

Alan


* nano_1.jpg (10.05 KB, 294x402 - viewed 23 times.)

* nano_2.jpg (8.2 KB, 301x420 - viewed 15 times.)
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W4AMV
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« Reply #20 on: August 03, 2019, 11:46:50 AM »

Here are the sides. Hope the moderator does not get upset...  Grin


* nano_3.jpg (5.75 KB, 216x476 - viewed 19 times.)

* nano_4.jpg (6.19 KB, 224x439 - viewed 10 times.)
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KD6VXI
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« Reply #21 on: August 03, 2019, 03:33:02 PM »

Id be willing to bet your friend could sell those.  Any idea on a price he'd want for one?  Smiley

--Shane
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W4AMV
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« Reply #22 on: August 03, 2019, 03:47:49 PM »

My recent conversation with him, Twelve and some change.

He and I are experimenting with a sun shield. But I think that added cost is in the noise.

 
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KD6VXI
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« Reply #23 on: August 03, 2019, 05:34:11 PM »

See your PM.  I'll take a case.

I'll feel much better about dropping this from the tower rather than the laptop and DG8SAQ VNWA or even the MFJ 259b!


--Shane
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KF7WWW
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« Reply #24 on: August 03, 2019, 07:38:19 PM »

Pm me also. I have one of these units on the way.
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