Hi,
I am a newbie here and on nanoVNA
Any online sources for how to use, without too much technicality, for antenna z, resonance, lc resonance and L inductance. Not interested in Smiths
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Re: Common ground and 2-port measuring
Miro, the nanovna is designed to measure this way - think of the calibration you do for a thru S21 measurement; it calibrates the error due to the cable and ground paths. For measuring the choke, there is no need to worry about this issue. Other issues are present which have a much larger effect on the resolution/accuracy of an S21 measurement - it is quite accurate for small values of Z, but gets less and less accurate as Z exceeds several k-ohms. But it is entirely sufficient to get a reasonable measure of the effectiveness of the choke, especially for the values of insertion loss and common-mode S21 attenuation. On Thu, Jul 7, 2022 at 7:23 PM Miro, N9LR via groups.io <m_kisacanin= [email protected]> wrote: Some really good suggestions, but let me highlight "my problem" here :)
I'll only focus on measuring S21 in differential mode using 2 port setup!
On the port 0 I connect shield and center conductor (as with any coaxial
transmission line), on the other port I do the same. Simple connection,
nothing fancy. Shield to shield, hot to hot :)
Now I have internally bonded ground between shields at Port 0 and Port 1,
and i ALSO have shield of the coaxial cable connecting grounds of those two
ports!!! THAT DOES NOT SEEM RIGHT!
Chances are that DUT (the current balun in this case) will lessen the
impact of the internally bonded grounds by acting as the current balun, but
what if CMRR is small - parallel ground paths will add some measuring error!
I still need to take a look at the S11 concept suggested by WB2UAQ with
shorted output and 1 port measurement of S11, but that still does not give
me S21 in differential mode!
So, how will internal ground bonding affect 2 port setup for
measuring S21 in differential mode?
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Re: Common ground and 2-port measuring
Some really good suggestions, but let me highlight "my problem" here :)
I'll only focus on measuring S21 in differential mode using 2 port setup!
On the port 0 I connect shield and center conductor (as with any coaxial transmission line), on the other port I do the same. Simple connection, nothing fancy. Shield to shield, hot to hot :)
Now I have internally bonded ground between shields at Port 0 and Port 1, and i ALSO have shield of the coaxial cable connecting grounds of those two ports!!! THAT DOES NOT SEEM RIGHT!
Chances are that DUT (the current balun in this case) will lessen the impact of the internally bonded grounds by acting as the current balun, but what if CMRR is small - parallel ground paths will add some measuring error!
I still need to take a look at the S11 concept suggested by WB2UAQ with shorted output and 1 port measurement of S11, but that still does not give me S21 in differential mode!
So, how will internal ground bonding affect 2 port setup for measuring S21 in differential mode?
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Anybody have any hints on getting Earthlink to stop blocking groups.io?
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Re: Common ground and 2-port measuring
I do this a little differently, for simplicity, as discussed in some of the
message threads (search for CMC, and you will find lots of methods/info
from discussions several months ago).
For insertion loss, with a coaxial coax choke like what you described, what
I care about is the loss through the center conductor when the shield is
working as a return path - so I just hook it directly to the coax port 0
and 1 connectors of the nano, and display the S21 loss curve in dB. A good
choke will have just a small insertion loss, typically less than .1 dB at
HF frequencies.
For common-mode rejection, what I care about is how much the shield
attenuates the signal - so I connect the shield only to the center
conductors of the port 0 and 1, and do another S21 loss curve. Then I see
20-40 dB of attenuation in a curve across 1-30MHz for my HF chokes. If I
want to see the impedance, I can also change the display to show R+jX and
get an estimate of the impedance, hoping for k's of ohms resistive and a
small reactive part. The measurement and values are not perfect, but is
easy to do. You can see a similar loss curve if you just hook the shield
across port 0, and display an S11 loss curve - but displaying the impedance
isn't correct in that setup, since it is the impedance of the reflection,
not of the choke.
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On Thu, Jul 7, 2022 at 2:25 PM WB2UAQ <pschuch@...> wrote: As you said, short the input terminals and the output terminals and
measure S21 between the terminals with them floating. With the phase and
magnitude of S21 the common mode Z can be calculated. There are files in
this discussion group that do the calculation. Save the s2p data and
insert it into the spreadsheets.
For insertion loss measure S11 (return loss format) looking into the DUT
with the output terminals of the DUT shorted. Half the return loss is the
loss thru the DUT.
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Re: Common ground and 2-port measuring
As you said, short the input terminals and the output terminals and measure S21 between the terminals with them floating. With the phase and magnitude of S21 the common mode Z can be calculated. There are files in this discussion group that do the calculation. Save the s2p data and insert it into the spreadsheets.
For insertion loss measure S11 (return loss format) looking into the DUT with the output terminals of the DUT shorted. Half the return loss is the loss thru the DUT.
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Re: Common ground and 2-port measuring
[Siegfried said: In both cases a common ground does not hurt so i connect both grounds together]
That's what I was hoping for :)
That common/internal ground (bonding) can't affect when measuring against 50ohm load (1 port measurement), but I was concerned how will that affect S21 (through loss).
Any "science" beyond empirical finding that internal bonding won't hurt? A gut filling tells me that there much be more to it when I have two ground paths in parallel - one internal and one through DUT.
When it comes to "how much power" - that would be great for another release - nanoVNA with legal power output (1k5W) and temperature sensor built in :) + other port that can handle these levels too! And battery to support all that!
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Re: Common ground and 2-port measuring
I measure through loss
And cm surpression
In both cases a common ground does not hurt so i connect both grounds together
And i measure swr
with the balun loaded with its nominal impedance.. 50 ohms.. Or 200 (for a 1 to 4).. Or for whatever it is made
Those three tests give you a good idea how well your balun or choke works
How much loss it has
How good it suppresses cm current
And in what frequency range you can use it... Whatelse do you need to know?? Maybe how much power it can handle.. Grin
Greetz sigi dg9bfc
Am 07.07.2022 22:25 schrieb "Miro, N9LR via groups.io" <m_kisacanin@...>:
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Found several articles and several answers/opinions on this topic :)
If I want to do 2 port measurement in a setup where the input and output
of the DUT do NOT have common ground (let's say an RF transformer, or a
simple current balun), how will internal common ground on nanoVNA ports
affect measurements.
Let's be even more specific - want to do some simple testing of an HF
balun. S21 for differential mode and for the common mode suppression. Just
for the sake of the argument, balun will be wound with a short (comparing
to lambda) piece of coaxial cable, either wound in air or on ferrite
toroid.
In the CMR mode I'l short both sides of the balun, connect to "hot" ends
of both nanoVNA ports, and "rely" on the grounds being connected
internally - is that correct setup?
In the differential mode how will that internal common ground affect
measurements as it will effectively short the current that is supposed to
go through the shield of the coaxial cable making the balun?
So, in one case (CMRR measurement) that internal common ground helps. but
in the other (differential) it does not.
All would be easier if ports on nanoVNA are not bonded internally and I
have an option to connect them or not :)
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Common ground and 2-port measuring
Found several articles and several answers/opinions on this topic :)
If I want to do 2 port measurement in a setup where the input and output of the DUT do NOT have common ground (let's say an RF transformer, or a simple current balun), how will internal common ground on nanoVNA ports affect measurements.
Let's be even more specific - want to do some simple testing of an HF balun. S21 for differential mode and for the common mode suppression. Just for the sake of the argument, balun will be wound with a short (comparing to lambda) piece of coaxial cable, either wound in air or on ferrite toroid.
In the CMR mode I'l short both sides of the balun, connect to "hot" ends of both nanoVNA ports, and "rely" on the grounds being connected internally - is that correct setup?
In the differential mode how will that internal common ground affect measurements as it will effectively short the current that is supposed to go through the shield of the coaxial cable making the balun?
So, in one case (CMRR measurement) that internal common ground helps. but in the other (differential) it does not.
All would be easier if ports on nanoVNA are not bonded internally and I have an option to connect them or not :)
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Re: Traces refresh rate slows down with fw 1.0.69
#nanovna-h4
On Wed, Jul 6, 2022 at 10:26 PM, <t.rohner@...> wrote:
HB9SFG
Hello and many thanks for the infomation. Good to hear, there is a solution that fixes the problem. The 1.0.53 is also for my Nano the latest version that worked without the mentioned issue. Recently I updated to 1.2.00, which is much more stable but also with this version I faced the same issue. The problem seems to be hardware dependent. I will look for version 1.2.02 and give it a try. Many thanks and 73 Gerd
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On Wed, Jul 6, 2022 at 10:06 AM, EB4APL wrote: Which Acrobat version are you using to open this file and others
generated by the deepl translator? I have version 9 Pro Extended and it
refuses to open it, saying that an updated version is needed. Checking
with the Acrobat update function it says that there is not any update
available.
It opens fine on one of my old computer using Adobe Reader 11 and also with the latest version of Adobe Reader DC for Windows. Roger
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Ubuntu PPA or .deb installation
Hello, is there possible to use a "standard" way (PPA, .deb) to install NanoVNA-Saver?
Thanks
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Re: Traces refresh rate slows down with fw 1.0.69
#nanovna-h4
Hello
I had the same problem you have.
For me, with a H4 also, FW originally was 1.0.39.
Then i updated and up until 1.0.53 the traces work at "normal" speed. (i tested this, starting from 1.0.69, it was slow like you describe it. 1.0.64 doesn't work at all on my H4, black screen)
I tested clear config and restart with 1.2.00, no luck. (i reduced the sweep points to 51 and it took "only" about 20 sek for a sweep, but no useful readout connected to my DemoKit 6.5MHz BSF)
Then i saw in the vna beta group, that there is a 1.2.02 version.
I installed it and heureka, it sweeps even faster, than 1.0.53.
I hope that helps
73 de HB9SFG
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Re: nanovna-saver/displayed charts/S11 R/ω & X/ω (?? / Hz)
OK. Thank you Simec Already, it works. But I don't see the notice.
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Hi Roger,
Which Acrobat version are you using to open this file and others generated by the deepl translator? I have version 9 Pro Extended and it refuses to open it, saying that an updated version is needed. Checking with the Acrobat update function it says that there is not any update available.
Regards,
Ignacio
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El 06/07/2022 a las 18:10, Roger Need via groups.io escribió: On Wed, Jul 6, 2022 at 06:03 AM, F1AMM wrote:
It's a pity that your pages are not in HTML; it would have allowed Chrome to
translate them to me in French, online. In English, I can't follow.
Use the deepl translator. It will translate pdf files and keep them in the same format as the original.
Attached is a translation to French of one of Arie Kleingeld PA3A English articles
Roger
Here is
--
El software de antivirus Avast ha analizado este correo electrónico en busca de virus.
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I found this online (
):
[image: image.png]
As with air wound inductors, the inductance for fixed ?r, the inductance
varies as the square of the number of turns. The ? in the above equations
should be the ?r of the toroid material times ?o (of free space).
So the scaling between 33 turns and 21 turns would be [21 / 33]^2 or
0.401. If you measured 36 ?H with 33 turns, you should have 33 ?H x 0.401
= 13.4 ?H with 21 turns. Of course, the 33 turns is with 0.1 mm and the 21
?H is with 0.2 mm. But with a larger core, I would expect greater
inductance than the original 0.1 mm core.
Bear in mind that the tolerance in ?r from unit-to-unit may be as much as
20%. This is quite normal even with toroids from the same batch from the
manufacturer.
Dave - W?LEV
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On Wed, Jul 6, 2022 at 4:29 AM F1AMM <18471@...> wrote: Hello
I have very little experience with toroids. I made some RUTHROFF
transformers but nothing more. On my cores, I note that the Al is not
constant. Is this normal ?
TORUS
====
Outside diameter ? 10 mm
Inner diameter ? ~ 5 mm
height 5mm
Self of 33 turns of ? 0.1 mm
--------------------------------------
Bridge measurement BF Z serie
120Hz: 36.75?H 0.443 Ohms
1kHz: 36.34?H 0.447 Ohm
10kHz: 36.08?H 0.455 Ohms
100kHz: 35.91?H 0.635 Ohms
Self of 21 turns of ? 0.2 mm
--------------------------------------
Bridge measurement BF Z serie
120Hz: 8.081?H 0.0764 Ohms
1kHz: 8.122?H 0.0764 Ohm
10kHz: 8.112?H 0.0771 Ohms
100kHz: 8.084?H 0.112 Ohms
Calculation of aL ? (it-is good ?)
=============
Self 33 turns: 33 nH/turn?
Self 21 turns: 18 nH/turn?
73 QRO
F1AMM (Fran?ois)
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
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On Tue, Jul 5, 2022 at 09:29 PM, F1AMM wrote:
Hello
I have very little experience with toroids. I made some RUTHROFF transformers
but nothing more. On my cores, I note that the Al is not constant. Is this
normal ?
Yes the Al will vary with frequency for ferrite toroids. The reason is that the permeability of the ferrite toroid varies with frequency and the Mix (31,43, 75) etc. has a significant effect. Powdered iron Al only varies slightly with frequency. Most of the online ferrite toroid calculators only provide good results at low frequencies. Here is an excellent online calculator for you to try >> Roger
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On Wed, Jul 6, 2022 at 06:03 AM, F1AMM wrote:
It's a pity that your pages are not in HTML; it would have allowed Chrome to
translate them to me in French, online. In English, I can't follow.
Use the deepl translator. It will translate pdf files and keep them in the same format as the original. Attached is a translation to French of one of Arie Kleingeld PA3A English articles Roger Here is
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Re: nanovna-saver/displayed charts/S11 R/ω & X/ω (?? / Hz)
And, speaking of Smith Charts, if you haven't yet discovered SimSmith, give
it a try. It's free.
There is also an excellent tutorial linked from that site.
Dave - W?LEV
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On Wed, Jul 6, 2022 at 4:04 AM F1AMM <18471@...> wrote: Thank you Victor
Hi there
I did well to tell you clearly what I did not understand. Our linguistic
difference plus character encoding problems had greatly scrambled the
transmission. The ? which had been transformed into mu was formidable.
The ""S11 R/Ω & X/Ω"" is what is written on the graph of nanovna-saver
In summary what I understood:
From S11, nanovna-saver calculation Z
When you write Z'=Z/ω you are using the real Z or the reduced z=Z/Zc where
Zc is the normalization impedance (50 ?).
Then nanovna-saver draws the graph of Z' as a function of F= ω/2π by
separating the real part from the imaginary part.
I do some development in C#. I wrote a grinder to, from a CSV, draw a
graph in a .DXF The grinder was in fact to make topographic plotting. These
.DXF (like .DWG but ASCII) I manipulate them with nanoCAD, a version of
which is free. It turns out that in the Smith chart the rectangular
coordinates of the chart (horizontal and vertical) are the coordinates of
S11 (the normalized reflection coefficient with respect to Zc). I have a
Smith chart in bitmap as well as a vectorized chart in my .DXF and I can
superimpose quite easily:
-Theoretical curves, derived from calculations
-Measurements, by processing nanovna-saver .S1P files
It is with sed I transform the .S1P into .CSV I can control this .CSV in
Excel and do calculations on it. It is a very powerful aid.
73 QRO
--
F1AMM Fran?ois
-----Message d'origine----- De la part de Victor Reijs
Envoyé : mardi 5 juillet 2022 23:13
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
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I have a lot of bad luck with Adobe. I had a CS3 version with Acrobat 8 pro (+ license) but it refuses to work. With Adobe it's hard problems. It is therefore insoluble for me to translate your .pdf and it is a pity.
The EZNEC notice is provided, among other things, in Word (.doc). It's impeccable: I converted it into HTML and Google translated it for me into almost perfect French. At least with Google it works.
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Gooser5000
Roger Need
Nickko - ON9NG
