开云体育

In case nobody has made this public, below find some part numbers for useful or absolutely required fittings and adapters.

A couple of each are en route to me right now. (From Digi-Key. Not Mouser. I gave up on Mouser after three orders in a row were screwed up, costing me serious coinage and time lost for five different jobs.)

Digi-Key part numbers:
ACX1242-ND SMA Jack-Jack (like the one shipped with most NanoVNAs)
ACX1240-ND SMA Plug-Plug (exactly the opposite polarity of the 1242 above. Might be handy setting up a DUT, you never know...)
ACX1246-ND SMA gender - mender. This is a male to female converter
J10097-ND SMA to BNC converter. Most of my stuff is UHF connectors, SO-239 / PL-259, but I already have adapters for BNC for that.

Digi-Key (and likely Mouser, if you prefer them - I don't have a dog in this hunt so get it where you like) has roughly a thousand different SMA to --something-- adapters and fittings. (The SMA to SO-239 adapters are way-stupid-over-priced as far as I can tell, but most of the rest are just ugly expensive, same as everywhere else... Adapters and connection cables and fittings are going to wind up more expensive than the VNA itself, I am afraid.)

--
Wes Will
N9KDY

Saw this on eBay. Anyone have gerber files for something like this?

And you can always communicate directly with the ChibOS to get data in text
mode using a terminal program.

Ah!! THAT is what I needed. CLI it shall be. Thanks. Do you know if it is limited to 9600 BPS (BPS not BAUD)? My serial ports go a lot faster than that, and I have some non-Chinese-pirated-JUNK USB-to-RS-232 converters....

No, I do not participate greatly in the distro wars. I've just had it up to my ears with hearing the lie about "sudo" being a security feature.

--
Wes Will
MS IT (InfoSec)
N9KDY

Dow-Key Microwave 411C-220832 12V relays I got a handful from equipment that we tossed into recycling at worksites. They never seen a signal larger than -10dbm and are perfect for circuits like this. None of them are older than 5 years and if they have switched more than 10 or 15 times in that time frame I would be utterly surprised.

Bilbo

Where did I purchase? eBay and it took about 4 weeks to arrive.

Why three, now 4, vnas? I wanted one of each of the identified versions to test whether one was better. Whether shields made a difference in performance.

Those tests are done and now I am paring down to two...... one mounted in my lab and one for my toolbox for the field.

WA8TOD

But the Taobao website is in foreign.

On 15 October 2019 at 22:03 SM Ling <sm.ling11@... mailto:sm.ling11@... > wrote:


If you are waiting to get another nanoVNA, you can get this when it is available on ebay or aliexpress. I got mine from Taobao direct.

But you need to solder in the connectors and the components.

Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937 825 5032
Amateur Radio G8IFF W8IFF and GMRS WRBV701, e-mail nigel@... www

Ahh the linux holy wars. I can assure you that nanovna-saver works fine on
Fedora.

It's a pure python program though it needs some libraries that are
available in the repository but the packages are named slightly differently
in different distributions. The pip3 instructions should be consistent,
though.

I think the other software choices are windows-specific. At least by
report, the hardware communication under wine isn't smooth.

And you can always communicate directly with the ChibOS to get data in text
mode using a terminal program. For instance minicom at 9600 8N1. The prompt
is ch> and 'help' gives a list of commands.

Paul Alfille K1PHA

If you are waiting to get another nanoVNA, you can get this when it is available on ebay or aliexpress. I got mine from Taobao direct.

But you need to solder in the connectors and the components.

On Mon, 14 Oct 2019 at 23:53, yza <yzaVNA@...> wrote:

#47 : Once Again

@Dr. David Kirkby from Kirkby Microwave Ltd - 14 October 2019 :
/g/nanovna-users/message/4907

Hello,

Hello,

After your suggestion, allow us, please, to also suggest to you,
once again, after the previous one with our message:

25 : The concept of Quantity today - 1 October 2019 :
/g/nanovna-users/message/3106

I am sorry, but you keep giving links rather than comment is very tiresome
for me.

| Finally, allow us, please, to comment that, in our humble

| opinion, regarding 'Understanding', there are the following
| types of human beings, according their personal tastes:
|
| (1) Those who don't want to understand, and those who want
| to understand, but when they don't understand then, according
| to their judging abilities, they put constantly the blame:
|
| (2) on the others,
|
| (3) on themselves, and
|
| (4) either on the others or on themselves, according to the state
| of their progress in the Knowledge

Sincerely,

gin&pez@arg

Your comments such as those above about the abilities and attitudes of
different people is seen as rude by myself.

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

One of the parameters specified for a VNA is the

* raw uncorrected source match and
* raw uncorrected load match.

The better the raw performance, the better the corrected performance.

I measured these best I could using my 8753ES VNA. Had these been poor, I
would have tried to improve them. But based on my sample, it is not
worthwhile trying to improve them.

My procedure was

1) Set 8753 to its minimum output power which was -22 dBm, as its default
output (I think +5 dBm), would have overloaded the NanoVNA.

2) Use a cable that came with the NanoVNA it is it quite flexible.

3) Added a 2 dB attenuator on the cable, for no other reason than to
protect my calibration standards.

4) Set the 8753ES VNA to use the 85033D or 85033E calibration kit. This has
the same parameters as my 85052B

5) Calibrated up to 3 GHz, which is the limit of my 8753ES - I do have a 20
GHz VNA, but below about 860 MHz, the 8753ES has better performance than
the 20 GHz VNA.

5) Measured return loss of port 2 with the NanoVNA powered on and off.
There was some difference, but only a few dB. As you can see from the
photograph, the worst return loss on the load is 17.7 dB.

6) I measuring the source port with the NanoVNA powered on. I could find
no way to stop the source completely messing up the measurements. Setting
the frequency down below 100 kHz still screwed up measurements at 900 MHz.
There were huge spikes. Note that the 8753ES VNA source power would have
been around 10 dB less than the NanoVNA output power.

Ignoring the very significant spikes, I do believe that the return loss of
the source wasn’t changing much whether the NanoVNA was powered up or not.
Anyway, the worst case return loss at the source, whilst powered off, was
28 dB.

In comparison, the guaranteed performance of my 8720D VNA over the range of
50 MHz to 2 GHz is

*HP 8720D (guaranteed)*
*Source match: 12 dB*
*Load match: 22 dB*

*NanoVNA (sample of 1)*
*Source match: 28.0 dB*
*Load match: 17.7 dB*

So my one sample, the NanoVNA had a much better source match than the
8720D, but a little worse load match.

Since I know that the NanoVNA was getting worse as the frequency was swept
up to 3 GHz, if I did add the firmware that went to 1500 MHz, I might
consider adding a small attenuator or resistor on the load to improve the
load match, but to be honest I am only likely to do reflection measurements
up to 1296 MHz on the NanoVNA, so the match at port 2 would be irrelevant.

I didn’t think until after I had performed a 1-port calibration on the
8753ES, that it might have been worth measuring the isolation between the
two ports on the NanoVNA. The 8753ES has a system dynamic range of 110 dB,
which would have dropped to 90 dB at a much reduced output power. Probably
good enough, but if not reducing the IF bandwidth, increasing the output
power and averaging would have all helped.

Anyway, I thought it interesting, and based on my sample at least, any
attempt to improve the match at the ports would be best done on the
receiver port rather than the source port, but it’s pretty good.

--
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

#49 :
first details of our final report 1 :
nominal values comparison :
our [NanoVNA] ~ our [VNA]
-
#30 : our final report 1 - 6 October 2019 :
/g/nanovna-users/message/4179
-

Hello,

Allow us, please, to present the first details of our
final report 1 regarding the Nominal Values of Rho
for our [ref2007box], as they resulted by using
our [VNA] and our [VNA]:

Rho Magnitude:
[VNA] : CYAN - pre-calibrated
[VNA] : BLUE - Nominal Values
[NanoVNA] : MAGENTA - pre-calibrated
[NanoVNA] : RED - Nominal Values:


Rho Argument:
[VNA] : CYAN - pre-calibrated
[VNA] : BLUE - Nominal Values
[NanoVNA] : MAGENTA - pre-calibrated
[NanoVNA] : RED - Nominal Values:


Sincerely,

gin&pez@arg

49#

I would be interested in finding that out also.

Thanks, Dick, W1KSZ

Sent from Outlook<>
________________________________
From: [email protected] <[email protected]> on behalf of David Hartley <dehartley@...>
Sent: Tuesday, October 15, 2019 4:11 PM
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] Nanovna-F is here

Warren, where did you purchase your NanoVNA-F?
Dave

On Tue, Oct 15, 2019 at 05:26 PM, Kurt Poulsen wrote:

You missed to show us a sweep of the coax cable after tuning to celebrate the
victory ?

Kurt,

Please find attached below the Smith Chart after tuning the parameters. The S11 plot after tuning is the last chart in the first post #4963 above.

I think there is a misspelling in so far you used F for the inductance and H for the capacitance.

I was just reporting what is in the Calibration standards form on nanoVNA-Saver. I am not sure how these are implemented. The image of that form after tuning is attached as (LoadTuning.png) below as well. You may notice that I also did some minor tuning on the load and the Through offset delay.

--
Bryan, WA5VAH

Hi Bryan

Congratulation. Tweeking parameters in NanoVNA-saver is great fun. You missed to show us a sweep of the coax cable after tuning to celebrate the victory ?

I think there is a misspelling in so far you used F for the inductance and H for the capacitance, anyway it does not matter it is the numbers and the sign in front which provide the results.

Kind regards

Kurt



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af bryburns via Groups.Io
Sendt: 15. oktober 2019 23:28
Til: [email protected]
Emne: [nanovna-users] Am I Fixing my BNC Calibration using Calibration Standards Adjustments in nanoVNA-Saver 0.1.2



Folks,



Because of convenience and several other factors I usually use my nanoVNA through SMA to female BNC connectors. As a result, I calibrate both the nanoVNA and nanoVNA-Saver through the SMA to BNC connectors. One reason I do this is to avoid changing the connector mating to the SMA connectors on the nanoVNA.



I realize that BNC calibration kits are notoriously poor. Mine is no exception. The open I use is the female BNC to SMA adapter that is connected directly to the nanoVNA. Also, the BNC short that I use is likely to have some inductance because there is no insulation around the shorting pin. And, the shorting plane cannot be very close to the center pin of the female BNC even when it is properly connected to the mating connector. The 50-ohm load I am using is 50.0 ohms at DC based on a precision ohmmeter measurement. It does compare quite favorably with other terminations that are rated up to 3 GHz when measured on wider bandwidth VNAs.



With this cal kit, and doing both the nanoVNA calibration and the nanoVNA-Saver calibration, I get a nice clean dot in all of the right places. The short does register on the left side of the Smith chart, the load in the center and the open at the far right side as it should be after the OSLT calibration. However, we know that issues remain. The big question is: How to fix them or determine what errors may exist?



Some of the issues can be most easily observed by connecting a fairly short length of good, low-loss 50-ohm coax on the CH0 port and observing S11 on a Smith chart or looking at the return loss in dB over the frequency range from 50 kHz to 900 MHz. The cable used in the measurements shown in the attachments is a 20" (~0.5m) length of RG213 which has SMA connectors on both ends. It was connected to the BNC through a male-male BNC adapter and a female-BNC to female SMA connector. Yes, this is maximum adapter usage to connect the SMA cable to the SMA connector on the nanoVNA. But, the task here is to determine what is going on with the BNC calibration. My experience says that at frequencies below 900 MHz all of the connectors I am using should be pretty good. The first 2 plots I have attached show the result. I also used a commercially manufactured (surplus) piece of RG-233 with BNC male connectors with very similar results. So, this is definitely ans issue and most likely with the calibration.



Taking a careful look at the figure below contained in "Smith-RG213-WithoutCalTuning.png" I observe at least a few problems. 1) The plot should stay within the Smith chart but does not. 2) The circles which should proceed around the Smith chart in a counterclockwise direction are a) not circles and b) not centered on 50 ohms. Similar issues are observed when looking at the plot in the file "S11-RG213-WithoutCalTuning.png". Clearly their should be no positive values in the plot but there are. Furthermore, there is significant ripple in the plot caused by issues that are not likely the short cable.



So, I asked myself the question: "Can I manipulate the "Calibration standards" parameters in the nanoVNA-Saver application to fix what is wrong with the calibration?" I hasten to point out that I do not have access to high-quality measurement equipment and therefore I am left to figure out what is lacking in my BNC calibration kit. Here is what I did.



I began to try first of all to fix the open calibration by continuing to observe the Smith chart as I changed the "open" parameters C0 and the offset delay. Also by blowing up the scale on S11 phase I could see that using the BNC female as an open there remained a negative going and somewhat quadratically increasing phase ramp at frequencies above 500 MHz which could be due to the capacitance in the BNC female I was using as an open. I found that I could get rid of this negative going and quadratically increasing phase ramp by setting the "Open C0" value to 1100 e-15 H. With this setting the "hook" was removed and a linear phase trend remained. However, with that correction in place, the entire phase had a linear phase ramp. Adjusting the time-delay offset to -55 ps I found that I could then level the phase and get less than 0.4 degrees of phase deviation from zero degrees all the way from 50 kHz to 900 MHz. This seemed to me to be a big improvement. Clearly this is an empirical result but it could be a real description of the difference between a female BNC connector and a real open circuit. After these two adjustments the curve shown in "S11-RG213-WithOpenOnlyTuning.png" was collected. This is an improvement in that the trend in the S11 data is now approximately correct; however, large ripples remain,



During the adjustments of the open parameters, I continually looked at S11 in dB and S11 phase to make sure that what I was adjusting was making the phase more constant over frequency and S11 amplitude move in a correct direction (downward at the high end of the sweep.)



I then began to adjust the tuning parameter "L0" for a short. After a few guesses, I arrived at an adjustment for the short parameter of 1200 e-12 F. Said another way, this is like 1.2 nH of inductance is in the short I am using when compared to a real short. This is plausible for the short which is clearly not at the reference point which I consider to be the end of the center conductor for the female BNC center pin of the adapter to SMA. After this additional adjustment I created the chart shown below as "S11-RG213-WithCalTuning.png". I observe the following 1) There are no longer positive values - a definite improvement. 2) The trend is fairly monotonic out to 900 MHz but not perfect. 3) I haven't included the data for this, but the return loss out to at least 300 MHz is now almost exactly (within <0.02 dB) twice the measured S21 loss of the RG213 cable. Before the adjustments listed here, this was clearly not the case. Because there seems to be a limitation of 4 attachments in this forum, I did not include the S11 Smith chart below; however, the plot is now completely within the Smith chart, the circles get smaller as the number of times around the Smith chart increases, and everything is much more nearly centered on the Smith chart. These are all what I expect for this fairly simple measurement. I can put the Smith chart in a separate post if there is interest in it.



Is this really an improvement or am I kidding myself by tweeking parameters to improve the results of this simple measurement? My opinion is that it is a definite improvement and an approach that other may want to explore. I welcome your comments.



--

Bryan, WA5VAH

Warren, where did you purchase your NanoVNA-F?
Dave

I would like to set up Cal Files for different parts of the
Spectrum. One procedure I have talks about doing that,
but one of the steps (after setting the Frequency Range)
is to hit "Reset".

Now doesn't that delete "All" Cal data ?? Or by setting a
different Frequency Span cause you to create a new Cal
data file while preserving the default Frequency Span
Cal data file ?

Thanks, Dick, W1KSZ
Sent from Outlook<>

On Tue, 15 Oct 2019 at 22:03, alan victor <avictor73@...> wrote:

True, however, I was thinking forward as I understand a 3 channel nano
receiver is under development. Further, the technique for obtaining true 2
port s data currently requires unbolting the test device and turning it end
for end. Not sure the calibration in that process would hold up. Thoughts?
Unless a simple after market S parameter test set is developed.

*There are several reasons I believe TRL calibration is not too practical
on a low-cost VNA.*

1) The length of the line section needs to be between 20 & 160 degrees
electrical length - ideally 90 degrees.



So to work at 1 MHz, where the wavelength is approximately 300 m, you need
a line section which is a *minimum* of 300*20/360=16.7 m long, and ideally
300/4=75 m long. This really makes TRL impractical below a few hundred
MHz.

2) As far as I an aware, TRL calibration requires a VNA with an S-parameter
set, and *4 independent receivers.* These are the a1, b1, a2 and b2
receivers. So you need one local oscillator split 4 ways to go to 4
different mixers The output from each mixer has to go to a different
receiver. You can’t switch one mixer and one receiver to measure different
things.

I haven’t looked at the block diagram of the NanoVNA, but I suspect it uses
just one mixer and one receiver, which is what all simple VNAs do to keep
the cost down.

I would not be surprised if the cheapest VNAs from Keysight don’t have 4
receivers.

The real big advantage of a 4 receiver VNA is the ability to do unknown
thru calibration.



That would be the biggest advantage of a 4-receiver VNA to me.

I attach a block diagram of a 3-receiver VNA (top) and a 4 receiver VNA
(bottom). I believe that you will find it considerably more complicated and
so expensive than a NanoVNA.




--
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

On Tue, 15 Oct 2019 at 04:16, Dr. David Kirkby from Kirkby Microwave
Ltd <drkirkby@...> wrote:

1) Download the firmware source code

Yes, that's easy enough

Go for it!
It will all make more sense after looking at ttrftech's Github and
downloading the source.
--buck

But why do you have more than one NanoVNA?? Am I missing out on something?? (I understand getting a -F in addition to the original)...
Mike WY6K


"... somewhere in the distance, there's a tower and a light, broadcastin' the resistance, through the rain and through the night..."

Good information.? I have one mystery though - what do you do with 3 NanoVNAs?? Why multiples?
Mike WY6K


"... somewhere in the distance, there's a tower and a light, broadcastin' the resistance, through the rain and through the night..."