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VNA shootout


John AE5X 2021/06/25 15:57

I'm as interested as anyone else who might have one to know the accuracy and reliability of these affordable VNA's, whether nano- or the one from SDR-Kits.

I have a variety of VNA's available but am lacking the SDR-Kits model. Wouldn't it be nice if we knew where it stood compared to the newer nanoVNA's costing a fraction of the price for the same dynamic range and a higher upper frequency limit?

Also, how do the hobby VNA's compare to lab-grade VNA's at HF and up to 1.2 GHz?

If you own an SDR-Kits VNA, can do without it for 3 weeks and trust me to return it to you, please see my offer here:

https://ae5x.blogspot.com/2021/06/vna-shootout.html

TNX/73,

John AE5X
--

win7 hslaw 2021/06/25 19:56

Hi John- There’s a pretty good video put out by W2AEW – he did a head-to-head on a real-old-school-VNA by HP vs. a NanoVNA-F.

I am not quickly able to tell you the video link (he numbers them) – but dig – it’s very informative.

-T





From: NanoVNAV2@groups.io [mailto:NanoVNAV2@groups.io] On Behalf Of John AE5X
Sent: Friday, June 25, 2021 3:57 PM
To: NanoVNAV2@groups.io
Subject: [nanovnav2] VNA shootout



I'm as interested as anyone else who might have one to know the accuracy and reliability of these affordable VNA's, whether nano- or the one from SDR-Kits.

I have a variety of VNA's available but am lacking the SDR-Kits model. Wouldn't it be nice if we knew where it stood compared to the newer nanoVNA's costing a fraction of the price for the same dynamic range and a higher upper frequency limit?

Also, how do the hobby VNA's compare to lab-grade VNA's at HF and up to 1.2 GHz?

If you own an SDR-Kits VNA, can do without it for 3 weeks and trust me to return it to you, please see my offer here:

https://ae5x.blogspot.com/2021/06/vna-shootout.html

TNX/73,

John AE5X
--

Siegfried Jackstien 2021/06/26 10:50

matthias dd1us made a comparison of a nanov2 with an hp 8753 e ...

so at least we know these tiny instruments show similar resuts as
professional gear

https://www.dd1us.de/Downloads/Brief%20comparison%20of%20NanoVNA%20V2%20with%20a%20professional%20VNA%20HP-8753E.pdf

greetz sigi dg9bfc

Joe Smith 2021/06/26 07:55

The title hooked me, but limiting the scope to what someone feels a ham needs seems far too constraining to be of much use.  I'm not being a ham or CB radio operator and will have to take your word that dynamic range is the most relevant spec for these groups.  You may want to start by asking the groups what metrics they are most interested in.  Detail your test procedures allowing others to repeat your tests using their equipment and contribute their results.

Personally, I see these low cost instruments being very valuable for education. I am not going to complain too much about their performance.  The biggest struggle I have had with the low cost VNAs has been finding stable firmware.

"So the more relevant spec of any of these VNA's would be their dynamic range, not the upper frequency limit. Besides, how many hams have a need for gear that measure much above 450 MHz?

Also, I only want to test VNA and TDR functionality. The two Keysight models will do much more but those functions are beyond the purpose of the comparative test, which basically is:

* Are the nanoVNA's toys? Let's find out definitively.
* What do I gain by spending extra $$$ on a more expensive hobbyist VNA?
* Does the data provided by the hobby VNA's compare well with lab-grade equipment?"

zeljko adzic 2021/06/26 17:05

https://www.facebook.com/k19radio/photos/pcb.3028759590737654/3010645012542859

On Sat, Jun 26, 2021 at 4:10 AM John AE5X <ae5x@juno.com> wrote:

Siegfried Jackstien 2021/06/26 18:02

Am 26.06.2021 um 16:55 schrieb Joe Smith via groups.io:
>
> The title hooked me, but limiting the scope to what someone feels a
> ham needs seems far too constraining to be of much use. I'm not being
> a ham or CB radio operator and will have to take your word that
> dynamic range is the most relevant spec for these groups.  You may
> want to start by asking the groups what metrics they are most
> interested in.  Detail your test procedures allowing others to repeat
> your tests using their equipment and contribute their results.
>
> Personally, I see these low cost instruments being very valuable for
> education. I am not going to complain too much about their
> performance.  The biggest struggle I have had with the low cost VNAs
> has been finding stable firmware.
>
> "So the more relevant spec of any of these VNA's would be their
> dynamic range, not the upper frequency limit. Besides, how many hams
> have a need for gear that measure much above 450 MHz?
>
i measure patch antennas on 13cm (2.4ghz) with a nanovna v2
>
> Also, I only want to test VNA and TDR functionality. The two Keysight
> models will do much more but those functions are beyond the purpose of
> the comparative test, which basically is:
>
> * Are the nanoVNA's toys? Let's find out definitively.
>
no toys ... the nanov2 go up to 3.5ghz and the v2plus4 to 4.4ghz

and they do measure exact (more or less)

> * What do I gain by spending extra $$$ on a more expensive hobbyist VNA?
>
higher dynamic range and wider measure area
>
> * Does the data provided by the hobby VNA's compare well with
> lab-grade equipment?"
>
yes they do (if you calibrate them well) ... look what matthias (dd1us)
found out

he compared the v2 with "professional gear" (HP)

https://www.dd1us.de/Downloads/Brief%20comparison%20of%20NanoVNA%20V2%20with%20a%20professional%20VNA%20HP-8753E.pdf

just compare the smith charts at the end of that file ... they are
identical (besides the different sweep range used)

greetz sigi dg9bfc

Joe Smith 2021/06/26 10:20

It's too bad the V2Plus4 design missed some of the basics.  Still, combine it with the original NanoVNA for low frequency narrow band work and you can have your cake and eat it too, for under $200.

Here I am looking at an 1GHz interdigital filter with the original NanoVNA, the V2Plus4 and one of my old relics (PNA).  The original NanoVNA performs like we would expect from a $50 VNA, but the V2Plus for the $120 I paid for it, really shines.

https://youtu.be/XaYBpPCo1qk?t=2746

John AE5X 2021/06/26 11:42

Nice video - I'm looking forward to receiving my V2Plus4, currently on a slow boat still moored in China.

John AE5X

OwO 2021/06/27 02:26

Preliminary nanovna v3 details.
https://nanorfe.com/nanovna-v3.html
https://groups.io/g/NanoVNAV3

aleks07111971 2021/06/27 02:42

Gabriel Hi!
Please give me the details of V3?
On what components will it be executed?
Will there be STM32 with firmware from V2plus4.
Will there be a display module?

OwO 2021/06/27 02:43

Likely two versions, one with display and one without.

B.M. 2021/06/27 11:57

with fpga and 3 or 4 adc's?

OwO <OwOwOwOwO123@outlook.com> schrieb am So., 27. Juni 2021, 11:43:

OwO 2021/06/27 03:00

Yes, FPGA + 3 ADCs, full two port.

benjamin 2021/06/27 03:06

sounds descent. I suspected that the dynamic range limitation of the open source 6 ghz VNAs was not due to isolation but due to noise, therefore the complicated machined alu case did not help so much.
How do you generate the LOs and Stimulus? With DDS + PLL? The LO that goes into the mixer does not need to be especially clean, but it would be nice if the stimulus signal does not have too many harmonics. Using PLL alone makes it difficult to generate low frequency signals without harmonics or would require many filters.

OwO 2021/06/27 03:15

It's PLL based, and the lower frequency limit is mainly bottlenecked by the mixers. I'll put up more information after more detailed testing is done.

benjamin 2021/06/27 03:37

PLL only is fine for 95% of all applications. Only when you measure nonlinear/active devices will it become important that the stimulus does not have harmonics. Therefore most professional VNAs use DDS with 100 MSPS or so for lower frequencies up to about 50 MHz or so and above that PLL. That way the harmonic filters can start at > 50 MHz.
Maybe u can do a pro version later with 4 receivers and clean stimulus which could then replace entry level pro VNAs.
For measuring amplifiers it would be nice to have an input step attenuator at port 2 (most pro VNAs have that as an option). Ot should be pretty cheap to include. Lowering the input power into the amplifier would increase noise of measurement. Without step att one would have to add an external attenuator after the dut, which is also not a big problem.
The ability to do some kind of power sweep would be nice, that way one can ie determine the 1dB compression point of amplifiers.

amirb 2021/06/27 03:48

what does PLL have to do with having or not having harmonics in the stimulus signal? answer: nothing

both agilent and R&S VNAs that I have use PLL synthesized stimulus signal down to 9kHz and 30kHz

On Sun, Jun 27, 2021 at 06:37 AM, <benjamin@menkuec.de> wrote:

benjamin 2021/06/27 03:55

have a look at the service manual of modern r&s VNAs....

benjamin 2021/06/27 04:07

and have a look at the harmonic content that the output of PLLs have, ie this one
https://www.analog.com/en/products/adf4351.html#product-overview

Harmonics of PLLs are multiples of the generated frequency, harmonics of DDS are multiples of samplerate. If u generate 10 Mhz with a 100 MSPS, harmonics start at 50 Mhz. If u generate 10 Mhz with a PLL, harmonica start at 20 Mhz.

namerati 2021/06/27 14:03

On Sun, Jun 27, 2021 at 03:37:11AM -0700, benjamin@menkuec.de wrote:
>PLL only is fine for 95% of all applications. Only when you measure nonlinear/active devices will it become important that the stimulus does not have harmonics. Therefore most professional VNAs use DDS with 100 MSPS or so for lower frequencies up to about 50 MHz or so and above that PLL. That way the harmonic filters can start at > 50 MHz.
>Maybe u can do a pro version later with 4 receivers and clean stimulus which could then replace entry level pro VNAs.
>For measuring amplifiers it would be nice to have an input step attenuator at port 2 (most pro VNAs have that as an option). Ot should be pretty cheap to include. Lowering the input power into the amplifier would increase noise of measurement. Without step att one would have to add an external attenuator after the dut, which is also not a big problem.
>The ability to do some kind of power sweep would be nice, that way one can ie determine the 1dB compression point of amplifiers.

See the Joseph Wu issue on Github regarding this:
https://github.com/nanovna-v2/NanoVNA2-firmware/issues/31

Measuring active devices has been talked about for some time now, and
there are some very interesting ideas out there.

n2msqrp 2021/06/27 08:08

Interesting! Will it be able to do compkete two port forward and reverse (s11
s12 s21 s22) measurements?



Mike N2MS

> On 06/27/2021 5:26 AM OwO <owowowowo123@outlook.com> wrote:

>

>
>

>
>

> Preliminary nanovna v3 details.
> <https://nanorfe.com/nanovna-v3.html>
> <https://groups.io/g/NanoVNAV3>

_._,_._,_

* * *

aleks07111971 2021/06/27 05:23

OwO
MAX2870?

OwO 2021/06/27 05:40

Yes it's full two port (all 4 S parameters).

n2msqrp 2021/06/27 10:23

Thanks. Does the V2plus4 do full two port measurements?



Mike N2MS

> On 06/27/2021 8:40 AM OwO <owowowowo123@outlook.com> wrote:

>

>
>

>
>

> Yes it's full two port (all 4 S parameters).

_._,_._,_

* * *

B.M. 2021/06/27 07:26

Thats an interesting idea to make a virtue of necessity but probably only works good for linear devices, because otherwise the harmonics can show up at different frequencies, which are not even harmonics, at the receive port. Having a clean stimulus is of course the best, but low price is also a key factor to make VNAs affordable for hobbyists, so after all keeping it simple can make sense. Harmonic free stimulus can be a thing for another version maybe in the 500 USD range.

Teton Amateur Radio 2021/06/27 08:47

I just got my NanoVNA V2 Plus4 a couple of days ago. Now you are making
me wish I wouldn't have bought it and waited for this new version.

Mick - W7CAT

----- Original Message -----
From: OwO
To: NanoVNAV2@groups.io
Sent: Sunday, June 27, 2021 03:26:07 AM
Subject: Re: [nanovnav2] VNA shootout

> Preliminary nanovna v3 details.
> https://nanorfe.com/nanovna-v3.html
> https://groups.io/g/NanoVNAV3
>
>
>
>
>
>
--
Untitled Document

zeljko adzic 2021/06/27 16:54

dear owo expected release date

On Sun, Jun 27, 2021 at 2:40 PM OwO <OwOwOwOwO123@outlook.com> wrote:

DavidC KD4E 2021/06/27 11:29

Estimated price $400?

Mine is on the way.

I'm guessing I'll get lots of use from it before being ready to spend 2x
more.

To think this all started at $50.

kd4e

Joe Smith 2021/06/27 09:17

I was hoping it would go the other direction and get us down to 10kHz.

Can it be used to make narrow band measurements of crystals?
Will the interface be documented allowing for custom applications to control it?

Joe Smith 2021/06/29 04:50

Back to your topic of having a VNA shootout.

"Since both the nanoVNA's and the SDR-Kits VNA's are designed for hams, I simply want to compare them in applications a ham might use - return loss of antenna, insertion loss and skirt shape of filters, etc - across the range of frequencies for which they are designed."

It looks like you have made a few updates to your blog.  I understand a few radio hobbyist have attempted to make their own narrow band filters.  I bought a V2Plus and Plus 4 to replace the original NanoVNA and discovered that it lacks the resolution needed to make these measurements.

Recently I have been playing around with using the original NanoVNA to measure power distribution networks.  The V2Plus4 is limited to 50kHz on the low end.  The firmware I use with the original NanoVNA supports 10kHz but once we get below 20kHz, the noise gets pretty bad.   Along the same lines, I recently bought an H4 for testing.  Sadly, the firmware wasn't stable enough to use.  Interestingly, someone was changing the firmware to allow it to run sub 1kHz.  If you check the following link, I posted some test results with this firmware compared with what was supplied and the noise is so poor they basically had made the unit useless.

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3586018/#msg3586018

You may want to consider adding the various firmware to your matrix as that will play a big part in how the product behaves.

Speaking of IF,  how many times were you in the middle of a project and noticed some abnormal spur, shift in the signal, etc in your data only to discover it was the VNA?

You mention dynamic range.  I had looked at a LibreVNA and once you get below 1MHz, the performance is pretty poor.

After reading several posts where people had damaged their low cost VNAs (looking at antennas)  I made a video presenting ideas on how you could possibly protect one (using both hardware and gray matter).   You may want to consider looking into how robust they are.  Not just mechanically but electrically.

I saw people posting about battery indicators.  Maybe you will want to consider battery life as well.

People have written me about procuring an 8753 to measure antennas.  Really!  I consider that series the workhorses of the industry.  Many are still in use today.  You may want to consider adding a few flavors of this particular boat anchor to your list.    Of course, if you detail your test procedure I suspect you would get a lot more feedback.

Rudi 2021/06/30 01:35

On Tue, Jun 29, 2021 at 01:50 PM, Joe Smith wrote:

>
> The firmware I use with the original NanoVNA supports 10kHz but once we
> get below 20kHz, the noise gets pretty bad.

Hello Joe,
I have measured with the basic nanoVNA and DiSlord firmware 1.0.50, 100 Hz bandwidth,
down to 1 kHz with low noise, see the screenshot below.
More details can be found at:
https://www.rudiswiki.de/wiki9/nanoVNA-Applications#WSPR_Audio_Filter

73, Rudi DL5FA

Joe Smith 2021/06/30 17:23

Hello Rudi,

If you feel that 1.0.50 is the hot ticket, post a link to the image and I will gladly give it a run.

Rudi 2021/07/01 01:14

On Thu, Jul 1, 2021 at 02:23 AM, Joe Smith wrote:

>
> If you feel that 1.0.50 is the hot ticket, post a link to the image and I
> will gladly give it a run.

Hello Joe,
There are newer versions from DiSlord (1.0.64) but I will append the version 1.0.50
for the nanoVNA, which I used for the audio filter measurement.
73, Rudi DL5FA

Joe Smith 2021/07/01 06:23

Rudi,

I'll run a regression test on it this weekend and attempt to run some basic tests with it.  If you followed that link, you know I had tried their latest firmware and had a lot of problems with the regression test.  I was able to roll back to an earlier version and used that to collect my data.   I'll post the results on EEVBLOG forum (link later) so I don't clutter the emails.  Thanks again.

Joe Smith 2021/07/01 17:07

Rudi,

I plan to post the results here:

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3599026/#msg3599026

Joe Smith 2021/07/02 07:47

Rudi,

I finished my evaluation of the image you supplied and have uploaded the data I collected. I included data taken from my vintage HP3589A as a sanity test.  While what I show seemed pretty straight forward, if you have any questions about the tests I performed, feel free to ask.

Teton Amateur Radio 2021/07/02 08:59

Okay, I'll ask where the results are?

Mick

----- Original Message -----
From: "Joe Smith via groups.io"
To: NanoVNAV2@groups.io
Sent: Friday, July 02, 2021 08:47:41 AM
Subject: Re: [nanovnav2] VNA shootout

> Rudi,
>
> I finished my evaluation of the image you supplied and have uploaded
the data I collected. I included data taken from my vintage HP3589A as a
sanity test.  While what I show seemed pretty straight forward, if you
have any questions about the tests I performed, feel free to ask.
>
>
>
>
>
>
--
Untitled Document

Joe Smith 2021/07/04 18:29

I had provided a link one post further back.

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3599026/#msg3599026

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