Re: Are any of the NanoVNA sold on Amazon any better or worse than any others? Is there a better U.S. site to order from?
One thing I do not understand is why connecting the port 1 and 2 grounds together should decrease performance. Shouldn't all grounds be connected together, and all of these grounds to the chassis? Every piece of RF equipment I have seen that has a metal chassis grounds the RF to the chassis in as many places as possible. The chassis both serves as a constant potential large capacitive body and as a RF shield. The nanovna PCBs I have seen for some reason have separation of the ground planes between port 1 and 2. I agree there should be a via fence between the ports, but shouldn't the ground be common between the two with no break in the ground plane? This is a feature of the edy555 design I do not understand. Leaving these two with a large break in the ground plane is basically having port 1 and port 2 ground pads acting as two sides of an antenna to pick up stray fields. On Tue, Dec 17, 2019 at 8:51 AM Gabriel Tenma White < OwOwOwOwO123@...> wrote: I'm pretty sure S11 directivity is a well defined parameter. It is the
(uncalibrated) ratio between the |S11| reading when measuring an ideal load
and the lowest |S11| reading when measuring loads with reflection
coefficient magnitude of 1 (checking just open and short is usually good
enough). I have just finished characterizing the first 5 samples of the V2,
and the typical uncalibrated directivity is >30dB up to 1GHz, >20dB up to
2GHz, and ~17dB up to 3GHz. People may also look at S11 floor, which is the
directivity after calibration. While this doesn't tell you the directivity
of the coupler it does tell you how much noise you are going to get in
practice, and it captures coupler performance as well: a bad coupler that
is unsensitive to load changes will cause the calibration algorithm to
amplify noise, leading to high S11 floor. V2 typical S11 floor is -50dB up
to 2GHz and -40dB up to 3GHz.
The other important parameter is S21 floor (not dynamic range!). S21 floor
is defined as the ratio between the |S21| reading with nothing connected
and the |S21| reading when a lossless thru cable is connected between the
two ports. S21 *dynamic range* also counts the positive gain headroom
before the receiver saturates, so it's misleading because you won't
necessarily be able to see the stopband of a filter with 50dB rejection if
your dynamic range is 50dB. You need a S21 floor of -50dB or better. The V2
with shields typically gives -70dB S21 floor below 2GHz and -60dB floor up
to 3GHz.
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Re: Are any of the NanoVNA sold on Amazon any better or worse than any others? Is there a better U.S. site to order from?
Here are plots before and after calibration.
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Re: errors of "error" models
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Re: Are any of the NanoVNA sold on Amazon any better or worse than any others? Is there a better U.S. site to order from?
I'm pretty sure S11 directivity is a well defined parameter. It is the (uncalibrated) ratio between the |S11| reading when measuring an ideal load and the lowest |S11| reading when measuring loads with reflection coefficient magnitude of 1 (checking just open and short is usually good enough). I have just finished characterizing the first 5 samples of the V2, and the typical uncalibrated directivity is >30dB up to 1GHz, >20dB up to 2GHz, and ~17dB up to 3GHz. People may also look at S11 floor, which is the directivity after calibration. While this doesn't tell you the directivity of the coupler it does tell you how much noise you are going to get in practice, and it captures coupler performance as well: a bad coupler that is unsensitive to load changes will cause the calibration algorithm to amplify noise, leading to high S11 floor. V2 typical S11 floor is -50dB up to 2GHz and -40dB up to 3GHz.
The other important parameter is S21 floor (not dynamic range!). S21 floor is defined as the ratio between the |S21| reading with nothing connected and the |S21| reading when a lossless thru cable is connected between the two ports. S21 *dynamic range* also counts the positive gain headroom before the receiver saturates, so it's misleading because you won't necessarily be able to see the stopband of a filter with 50dB rejection if your dynamic range is 50dB. You need a S21 floor of -50dB or better. The V2 with shields typically gives -70dB S21 floor below 2GHz and -60dB floor up to 3GHz.
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Re: Are any of the NanoVNA sold on Amazon any better or worse than any others? Is there a better U.S. site to order from?
On Mon, 16 Dec 2019 at 05:33, <hugen@...> wrote: There are more than 5 clones of NanoVNA-H at present, some are with
shielding cases. If you could produce a set of specifications, in a *format* used by Keysight, then people with the right equipment could compare the performance of one NanoVNA-H against and the specifications, and return ¡°clones¡± if they have an inferior specification. I have seen meaningless terms like ¡°S11 directivity¡±. I am *not* saying that a $50 VNA should have the same performance as a $100,000 VNA. If the system dynamic range is 50 dB lower, that¡¯s fine. Let¡¯s be honest, it is really part of the Chinese culture to counterfeit devices. The problem exists in much of Asia. You were once yourself of breaching the GPL. Have you ever reversed-engineered a product to produce a clone? But due to their wrong assembling, the performance decreases. With a well written specification, following closely the format of a major VNA manufacturer like Keysight, some users would be in a position to determine if the specifications are poorer. Then poor sellers would soon get a bad reputation. Assembling the shielding case is to isolate effectively, but if they connect the shielding case of CH0 with CH1, it will sharply decreases the
performance. These problems would be much reduced if we had a decent specification to compare against. Although some clones are with good performance, we could only make judgement after testing. I am quite annoyed, because some irresponsible
agents sell inferior clones which marks as my version, it is a serious
cheating. Just like you *were* doing with the GPL! Seriously cheating! I get the feeling that there are a I have updated NanoVNA-H to version 3.4 after I received much feedback from the community. It is under assembling&testing at present. It works well
till 1.5GHz in the present testing. Meanwhile, I changed the power chip and
the battery to 650mAH which further decreases the noise from the usb
charging. In addition, it could work 4 hours after these changes. If
everything goes well, the new version will come to the market on Dec.20. With what size and resolution of screen? The NanoVNA is very nice, but for many users, myself included, the screen size is its biggest problem. You could buy from Maggie through this link:
hugen
I am sure you will find a lot more buyers from Europe and the USA if you sold via eBay. Many small Chinese companies sell on eBay. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
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Re: Some test results using a NanoVNA
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OK, I see there is a problem that can be solved quite easily.
I have 3D printers and Laser cutters, so if you can give me till the New Year, I will work with you all to design and prototype a case between us.
Next you are going to ask the cost, I will just ask for the cost of materials and posting.
So if anyone is interested, let me know.
I can probably find the basic 3D design but I do not have an uncased unit, so I would need local people to me in Manchester, UK. to try and test.
If you think about it, it does not need to be the standard case out already, once we have the fitting for the VNA correct, then we can mod. as we wish, for us.
The offer is there, I just need time to set my 3D units up at home, but after the holidays please.
73 - Les - M0LPB
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Re: Are any of the NanoVNA sold on Amazon any better or worse than any others? Is there a better U.S. site to order from?
On Mon, 16 Dec 2019 at 05:33, <hugen@...> wrote: There are more than 5 clones of NanoVNA-H at present, some are with
shielding cases. But due to their wrong assembling, the performance
decreases. Assembling the shielding case is to isolate effectively, but if
they connect the shielding case of CH0 with CH1, it will sharply decreases
the performance. Although some clones are with good performance, we could
only make judgement after testing. I am quite annoyed, because some
irresponsible agents sell inferior clones which marks as my version, it is
a serious cheating. I have updated NanoVNA-H to version 3.4 after I
received much feedback from the community. It is under assembling&testing
at present. It works well till 1.5GHz in the present testing. Meanwhile, I
changed the power chip and the battery to 650mAH which further decreases
the noise from the usb charging. In addition, it could work 4 hours after
these changes. If everything goes well, the new version will come to the
market on Dec.20. You could buy from Maggie through this link:
hugen
-- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
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Re: Some test results using a NanoVNA
What's needed to connect my NanoVNA- to my Android phone to use the NanoVNA- Webb app? Just a usbc to usbc cable? Martin K0BXB On Tue, Dec 17, 2019, 5:35 AM Martin via Groups.Io <huyettmeh= [email protected]> wrote: So how do you measure inductance using it?
Could you tune a trap with it? How?
Thanks.
Martin K0BXB
On Mon, Dec 16, 2019, 5:30 PM Bob Albert via Groups.Io <bob91343=
[email protected]> wrote:
I too have been enjoying the amazing capabilities of this little jewel.
I now find that I can measure most parameters of passive components and
networks with excellent accuracy.
I can measurecapacitanceESRESLinductanceresistancedelayphase
angleSWRimpedanceself resonant frequencyQcrystal parameterscoaxial cable
parameters: characteristic impedance electrical length propagation
constant capacitance inductance lossesconnector capacitanceinductance of
wiresfilter parameters: pass band stop band matching impedanceantenna
parameters: SWR resonant frequency bandwidth spurious
resonances impedance line lengthspectrum analysis, sort ofCW frequency
Probably more, as I haven't exhausted the possibilities yet.
Most measurements come within a percent or two of that reported by my
expensive bridges. When there is discrepancy, I often can trace it to the
use of a different test frequency. Testing electrolytic capacitors isn't
too satisfactory, as they are pretty much worthless at any frequency the
nanoVNA uses. However the readings can be useful, showing how important it
is to bypass an electrolytic capacitor for high frequency.
I have two nanoVNAs just to make sure I can still use one if the other
breaks. My old fashioned fancy expensive boat anchor VNAs are still handy
for frequencies beyond the nano's capabilities.
Anyone with questions about how to set it up to measure any of this, feel
free to ask.
Bob K6DDX
On Monday, December 16, 2019, 02:07:34 PM PST, DuWayne Schmidlkofer <
duwayne@...> wrote:
I recently updated my blog with two posts showing the measuement results
I have obtained using a NanoVNA.
one shows the response of a multiband HF antenna. The latest one shows
the response of a step attenuator I recently built.
I must say that I am more than pleased with the results I have been able
to obtain with such an inexpensive instrument.
It has been interesting following some of the discussions about
calibration and the math involved with the VNA, but I am more interested in
what people are using it for real world applications.
--
DuWayne KV4QB
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Re: Some test results using a NanoVNA
So how do you measure inductance using it? Could you tune a trap with it? How? Thanks. Martin K0BXB On Mon, Dec 16, 2019, 5:30 PM Bob Albert via Groups.Io <bob91343= [email protected]> wrote: I too have been enjoying the amazing capabilities of this little jewel.
I now find that I can measure most parameters of passive components and
networks with excellent accuracy.
I can measurecapacitanceESRESLinductanceresistancedelayphase
angleSWRimpedanceself resonant frequencyQcrystal parameterscoaxial cable
parameters: characteristic impedance electrical length propagation
constant capacitance inductance lossesconnector capacitanceinductance of
wiresfilter parameters: pass band stop band matching impedanceantenna
parameters: SWR resonant frequency bandwidth spurious
resonances impedance line lengthspectrum analysis, sort ofCW frequency
Probably more, as I haven't exhausted the possibilities yet.
Most measurements come within a percent or two of that reported by my
expensive bridges. When there is discrepancy, I often can trace it to the
use of a different test frequency. Testing electrolytic capacitors isn't
too satisfactory, as they are pretty much worthless at any frequency the
nanoVNA uses. However the readings can be useful, showing how important it
is to bypass an electrolytic capacitor for high frequency.
I have two nanoVNAs just to make sure I can still use one if the other
breaks. My old fashioned fancy expensive boat anchor VNAs are still handy
for frequencies beyond the nano's capabilities.
Anyone with questions about how to set it up to measure any of this, feel
free to ask.
Bob K6DDX
On Monday, December 16, 2019, 02:07:34 PM PST, DuWayne Schmidlkofer <
duwayne@...> wrote:
I recently updated my blog with two posts showing the measuement results
I have obtained using a NanoVNA.
one shows the response of a multiband HF antenna. The latest one shows
the response of a step attenuator I recently built.
I must say that I am more than pleased with the results I have been able
to obtain with such an inexpensive instrument.
It has been interesting following some of the discussions about
calibration and the math involved with the VNA, but I am more interested in
what people are using it for real world applications.
--
DuWayne KV4QB
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Re: Simple example of interfacing Octave with nanoVNA
#octave
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Searching ebay.co.uk has the same issue, no cases just nanovna units themselves.
I made my own metal box, so not an issue for me.
Maybe the vendors have placed a .com or regional listing condition on them.
73 de Andy
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Re: Simple example of interfacing Octave with nanoVNA
#octave
On Tue, Dec 17, 2019 at 05:57 AM, <bryburns@...> wrote:
On Mon, Dec 16, 2019 at 02:17 PM, <erik@...> wrote:
You need to load the instrumentation library
To clarify how to load the instrumentation library use the Octave command:
"pkg load instrument-control" from the Octave command-line prompt. But don't
use the quote marks.
--
Bryan, WA5VAH
Hi to all , I've solved the problem . The instrument-control pakage was installed. The mistake is that I was using the COM14 , that need a different sintax like hCom = nanoOpen("\\\\.\\COM14") instead of original sintax hCom = nanoOpen("COM14:") To avoid this problem , I cleaned the register to free the not used COM port. Many thanks for the support Maurizio IZ1MDJ
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Re: Some test results using a NanoVNA
Hi Bob,
It's interesting, and the translator translated it, I just had to put "space" in the right places.
Still very understandable, thanks for the summary.
73, Gyula HA3HZ
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Re: Simple example of interfacing Octave with nanoVNA
#octave
On Mon, Dec 16, 2019 at 08:57 PM, <bryburns@...> wrote:
,,, To clarify how to load the instrumentation library use the Octave command:
"pkg load instrument-control" from the Octave command-line prompt. But don't use the quote marks.,,,
=================================================================================
You can also let your script load the instrumentation library by entering, pkg load instrument-control, at the beginning of the script. Refer to: .
- Herb
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Re: Simple example of interfacing Octave with nanoVNA
#octave
On Mon, Dec 16, 2019 at 02:17 PM, <erik@...> wrote:
You need to load the instrumentation library
To clarify how to load the instrumentation library use the Octave command: "pkg load instrument-control" from the Octave command-line prompt. But don't use the quote marks. -- Bryan, WA5VAH
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I was tought early on that all things mechanical were considered FTF.
That is file to fit...
toggle quoted message
Show quoted text
On 12/15/2019 9:00 AM, Frank S wrote: I had 3d printed some cases and some people were happy, some were not. Seems these things are all not the same and sometimes you need to shave some of the holes to make it fit -- John Ferrell de W8CCW "We must never become too busy sawing to take time to sharpen the saw." Source: Ergonomic Trends
--
John Ferrell W8CCW
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Re: Some test results using a NanoVNA
My message was gargled beyond recognition by whatever stupid software handled it.? <sigh>
Bob
toggle quoted message
Show quoted text
On Monday, December 16, 2019, 03:30:53 PM PST, Bob Albert via Groups.Io <bob91343@...> wrote:
I too have been enjoying the amazing capabilities of this little jewel.? I now find that I can measure most parameters of passive components and networks with excellent accuracy.
I can measurecapacitanceESRESLinductanceresistancedelayphase angleSWRimpedanceself resonant frequencyQcrystal parameterscoaxial cable parameters:?characteristic impedance?electrical length?propagation constant?capacitance?inductance?lossesconnector capacitanceinductance of wiresfilter parameters:?pass band?stop band?matching impedanceantenna parameters:?SWR?resonant frequency?bandwidth?spurious resonances?impedance?line lengthspectrum analysis, sort ofCW frequency
Probably more, as I haven't exhausted the possibilities yet.
Most measurements come within a percent or two of that reported by my expensive bridges.? When there is discrepancy, I often can trace it to the use of a different test frequency.? Testing electrolytic capacitors isn't too satisfactory, as they are pretty much worthless at any frequency the nanoVNA uses.? However the readings can be useful, showing how important it is to bypass an electrolytic capacitor for high frequency.
I have two nanoVNAs just to make sure I can still use one if the other breaks.? My old fashioned fancy expensive boat anchor VNAs are still handy for frequencies beyond the nano's capabilities.
Anyone with questions about how to set it up to measure any of this, feel free to ask.
Bob K6DDX
? ? On Monday, December 16, 2019, 02:07:34 PM PST, DuWayne Schmidlkofer <duwayne@...> wrote:
I recently updated my blog with two posts showing the measuement results I have obtained using a NanoVNA.
one shows the response of a multiband HF antenna.? The latest one shows the response of a step attenuator I recently built.
I must say that I am more than pleased with the results I have been able to obtain with such an inexpensive instrument.
It has been interesting following some of the discussions about calibration and the math involved with the VNA, but I am more interested in what people are using? it for real world applications.
--
DuWayne? KV4QB
|
Re: errors of "error" models
GIN&PEZ;
I am very much familiar with the feeling of "cautious optimism", and I completely respect, appreciate, and support your careful scrutiny of the process details. I am looking forward to reviewing your results, and replicating them independently.
--
73
Gary, N3GO
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Re: errors of "error" models
@Gary O'Neil , N3GO - 17 December 2019 /g/nanovna-users/message/8292Dear Gary, Thank you. Well, we are now proceeding carefully, step-by-step, by multi-checking and cross-verifying the results with all available independent procedures, including the [NanoVNA] internal one, as well as both of these you are mentioning, because our two experimental two-ports are consisting of DC Resistive Taus, with a third one being under construction, having in our minds to demonstrate all possible cases by three, representative, as much as possible, practical applications - if it is possible at all, of course, since we don't know and we will see. Anyway, up to now all of the results are too encouraging - permitting a cautious optimism - but we will see. #78'' : #78' was re-corrected 20 November 2019 /g/nanovna-users/message/7272#80: [S]-parameters from [Z]-parameters 2 December 2019 /g/nanovna-users/message/7657Best regards, gin&pez@arg
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OwO
gin&pez@arg
Dr. David Kirkby, Kirkby Microwave Ltd
Oristo
Les Brown
Gyula Molnar