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Thanks for the directions! Now I have both devices and both groups!

73 Dana VE3DS

Szia Zoli,
NanoVNA-H4-hez készített Bluetooth elérhet?séget AA6KL, nézd meg :
73, Gyula HA3HZ
--
*** nothing is permanent only change ( ) ***

Dear David,

Thank you for your answer, your proposal is a good idea, but I would like to use cpu gpio ports to control wifi communication...

Many thanks and 73,

Can't help with the software issue, but I would be interested in your approach to adding Wi-Fi. If it were me, I would try to use the USB C port, since the that port looks like a USB serial interface and hooking up through it would allow continuous updates to the firmware to keep working without having to recompile it each new release.

,to%20the%20number%20of%20ports.

73, Carey, WB4HXE

--
Carey Fisher
careyfisher@...

Yes, the "conventional" (meaning: widely published and often used) formula is:

Gamma = (Z - Zo) / (Z + Zo) where Z is the impedance in question and Zo is the reference impedance for the calculation

But ignoring what Zo actually means and assuming "Both, characterstic wave impedance of a transmission line, and Thévenin impedance (= generator side impedance) are the same or interchangeable, is an error.

Correct, instead, is (a properly different Gamma naming convention is missing yet, so I call them here Gamma1 and gamma2):

Gamma1 = (Z - Zo) / (Z + Zo) with Z = termination impedance, Z0 = characteristic wave impedance of transmission line

Gamma2 = (Z - Zs*) / (Z + Zs) with Z = termination impedance, Zs = source (or generator) side impedance.

Now to the very good point: "I anyway use 50 + j0 Ohm for the generator side":

In that case Zs = Zs*, and thus the difference between Zs and Zs* becomes none. This may be a reason, that the actual error
lasted so long.

The statement is ok, if only you want to match your transmitter to the rig end of the feed line. In such applications it really
doesn't matter.

But though very often used, this is not generally always what we might want to know.


Two examples of a complex generator impedance:

1. Think of a receiving antenna, having anything, but not 50 + j0 Ohms. That is quite common for most antenna heights,
especially, if it is also used far away from resonance. Here we have a generally complex generator impedance.


2. Think of a not well matched transmitter antenna's feedpoint after a lossy feed line.

You may think: "I have a tuner down in the shack at my transceiver. That should take care after adjustment to SWR = 1:1."

And that is, what many think.

What you don't see then is the SWR at the feedpoint. Your rig side 50 Ohm SWR meter sais 1:1, but up at the antenna feedpoint
we have a totally different story - especially on the low bands because of often electrically short antennas. We there may
perhaps have something like 10 - j 1000 Ohms feedpoint impedance trying to match the Thévenin equivalent up there
resulting from the 50 Ohm transmitter, the tuner and the (often quite lossy) feed line. All these influences together may
produce a feedpoint SWR of some 1:10 resulting in total system losses of some 10 dB or more.

The reason to use the above Gamma2 is: It is no longer referenced to 50 + j 0 Ohms, but there at the feedpoint must be
referenced to whatever Thévenin impedance you have there after tuner effect and transmission line losses.

The theroretically (that is: for lossless systems ONLY) valid theorem, "If matched in one place, the system is matched in all places"
does no longer hold in such cases.

Need an illustration?
This one is from DL1JWD:

Take a shortened G5RV (or Zepp) type antenna on 3.5 MHz: 2 x 10m dipole length, 15m CQ553 ladder feed line, and a tuner
for SWR=1:1 at the transmitter.

In spite of the nice SWR = 1:1 down there, up there we have an SWR of some 1:10 (referenced to the Thévenin generator (or TX) side impedance up there, that is relevant for good real power transfer at the feedpoint).

Did you expect that? Perhaps not. It is just a little beyond the "plug and play", I admit, and certainly not needed for most local QSOs.

So, as we can see, certainly not always, but sometimes we may need and want to use Gamma2.

This is what I prefer: Forget unnecessary (due to some false assumption) details that may make it work well enough sometimes.
Instead, use a formula that yields correct results.

In earlier times - when complex calculations were difficult to do by hand - some approximations would do and were helpful.
Today we have easy computer possibilities for complex calculations. No need to neglect the Gamma1 and Gamma2 difference.


73, Hans
DJ7BA


-----Ursprüngliche Nachricht-----
Von: [email protected] <[email protected]> Im Auftrag von af5fx
Gesendet: Mittwoch, 3. Juni 2020 17:36
An: [email protected]
Betreff: Re: [nanovna-users] out of "Presentation on the NanoVNA for the raileigh Radio Society", Now: "False Return Loss Calculations"

Hi everyone,

Interesting discussion. A point of clarification though is that conventionally, the definition of Gamma (reflection coefficient) is:

Gamma = (Z - Zo) / (Z + Zo) where Z is the impedance in question and Zo is the reference impedance for the calculation

The formula in the preceding post appears to have a Zs* in the numerator which is not consistent with the standard definition of Gamma. It's probably from a different context. But, as far as NanoVNA goes, I would think that any reported results should follow conventional definitions of parameters for consistency with standard measurement practices. On that note, the following article is a derivation from basic principles where formula (3.12.10) is the standard definition:
(Ellingson)/03%3A_Transmission_Lines/3.12%3A_Voltage_Reflection_Coefficient

And, for what it's worth, I couldn't resist the temptation to throw in a few points of support for some of the other posts. While the discussion seemingly is centered around an example where Zo = 100 - j100 rather than the more conventional Zo = 50, that is inconsequential to my points:

1) Since Gamma is the ratio of the output (= reflected signal) to the input (= incident signal) it is a "gain" signal as are all S-parameters. It must be < 1 for any passive circuit since a passive circuit cannot add energy.

2) By the definition of S-parameters, it turns out that Gamma = S11 (or S22). So, |S11| must also be < 1 for a passive circuit.

3) Expressing Gamma in dB's is common practice and would actually result in a return gain which for a passive circuit would have to be a negative number. Most VNA's report S11 in dB which would be 20*log10(|S11|) and it would be negative for a passive circuit. While many call this return loss, that is loose nomenclature. Strictly speaking it should really be called return gain in this context.

4) For convenience one can use return LOSS which is the negative of value in dB's or the reciprocal in linear units such as Gamma. Thus, for a passive circuit return loss would have to be a positive value, in dB. And, of course, that means it would be - 20*log10(|S11|) or equivalently + 20*log10( 1 / |S11| )

Definitely easy to get tripped up in the signs. I have probably missed the point of this discussion but just wanted to throw in my two cents. Sorry if it's gone off topic. I didn't want to add to the confusion but instead support some of the later comments on the topic.

Darrell - AF5FX




--
Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft.

No, even though that could be a practical consequence. But that's not what I had in mind,
as - I think - it is possible to reverse the RL sign of the NanoVNA per gusto as individually wanted.

There are enough people of "another school", that strongly insist in the opposite of what I showed.

Trevor S. Bird, former IEEE chief editor, said, roughly a third of all RF papers turned in to the IEEE for publication,
had wrong sign RL. This, even though he had not yet seen my point in his article, as I showed it to him later.

However, none of them - to my knowledge - ever could show that the phenomena on a transmission line
of a certain characteristic wave impedance and the (Thèvenin equivalent of a) generator side impedance
are the same or else anyway share the same identical Gamma formula. This is just a very widely spread, false
assumption. Actually, as long as better power transfer is what we want, we have to use two different "Gammas",
one for each physical phenomenon.

That's what I wanted to demonstrate. So far I found a number of highest grade RF competence university
professors, who support this and who now share my with view me and have given the derivation as a proof.

Nevertheless, there are still so many (forgive me, would you?) "stubborn" adherents of the false assumption "school".

In respect of of them it is good to be able to change the sign of RL.

One - as I can see it, regrettable - consequence is: A programmer of the best general RF application programs available today stubbornly holds the opinion, that even negative SWR is correct, as such adherents of that school think, in a passive lumped
element circuit |Gamma| can be > 1.0. So, instead of a correct SWR, what you may get there is a numerically wrong and even
negative sign SWR. Sri. Who can convince such adherents of that school? I tried hard, but I couldn't.

I hope this helped the ever growing NanoVNA users to not just believe all the RF papers or even programs in every aspect,
but to sometimes check by derivation themselves, as errors are human, and are widespread, too.

73, Hans
DJ7BA



-----Ursprüngliche Nachricht-----
Von: [email protected] <[email protected]> Im Auftrag von randmental
Gesendet: Dienstag, 2. Juni 2020 20:40
An: [email protected]
Betreff: Re: [nanovna-users] out of "Presentation on the NanoVNA for the raileigh Radio Society", Now: "False Return Loss Calculations"

Does all of this mean that the RL on the NanoVNA and VNA Saver are wrong and should be positive? Deon

Hi Darrel,

From the formal and scientific point of view, this all can be discussed.

Well, as a radioamateur I don't really care about Plus or Minus. The nanoVNA is the most used VNA amongst hams in PA-land.
I know what loss is,? I know what gain is, I know what reflectioncoefficient etc is,? and I know how the dB-scale works.
That's enough for me to express myself to others and do my teaching to hamradio students.

:-)
My two eurocents...

73,

Arie PA3A

I recommend this group where they can hopefully answer it:
/g/NanoVNA-V2
73, Gyula HA3HZ
--
*** nothing is permanent only change ( ) ***

Hi everyone,

Interesting discussion. A point of clarification though is that conventionally, the definition of Gamma (reflection coefficient) is:

Gamma = (Z - Zo) / (Z + Zo) where Z is the impedance in question and Zo is the reference impedance for the calculation

The formula in the preceding post appears to have a Zs* in the numerator which is not consistent with the standard definition of Gamma. It's probably from a different context. But, as far as NanoVNA goes, I would think that any reported results should follow conventional definitions of parameters for consistency with standard measurement practices. On that note, the following article is a derivation from basic principles where formula (3.12.10) is the standard definition:
(Ellingson)/03%3A_Transmission_Lines/3.12%3A_Voltage_Reflection_Coefficient

And, for what it's worth, I couldn't resist the temptation to throw in a few points of support for some of the other posts. While the discussion seemingly is centered around an example where Zo = 100 - j100 rather than the more conventional Zo = 50, that is inconsequential to my points:

1) Since Gamma is the ratio of the output (= reflected signal) to the input (= incident signal) it is a "gain" signal as are all S-parameters. It must be < 1 for any passive circuit since a passive circuit cannot add energy.

2) By the definition of S-parameters, it turns out that Gamma = S11 (or S22). So, |S11| must also be < 1 for a passive circuit.

3) Expressing Gamma in dB's is common practice and would actually result in a return gain which for a passive circuit would have to be a negative number. Most VNA's report S11 in dB which would be 20*log10(|S11|) and it would be negative for a passive circuit. While many call this return loss, that is loose nomenclature. Strictly speaking it should really be called return gain in this context.

4) For convenience one can use return LOSS which is the negative of value in dB's or the reciprocal in linear units such as Gamma. Thus, for a passive circuit return loss would have to be a positive value, in dB. And, of course, that means it would be - 20*log10(|S11|) or equivalently + 20*log10( 1 / |S11| )

Definitely easy to get tripped up in the signs. I have probably missed the point of this discussion but just wanted to throw in my two cents. Sorry if it's gone off topic. I didn't want to add to the confusion but instead support some of the later comments on the topic.

Darrell - AF5FX

I have just received my V2 from Tinder after 40 days waiting.
Question:

1. What type of LiPo 3v battery is best for this unit? Can you point me to a source in N.A?
2. Does anyone have a case design that can print? (I think someone in Germany had but can’t find it )

Thanks
Dana VE3DS
Toronto

Jon-G0MYW here is a link to a 7zip file with two scripts a readme.txt and a pdf. Instructions are in the Readme.txt file for installation. This has been tested on LinuxMint 19.3, Ubuntu 20.04, and Zorin OS 15.2
Good luck

"!AgFEFnTEaTczgusGZtrbgIoizUJh1A?e=AS5TCc"

Jon, others,

I successfully installed NanoVNA Saver under Ubuntu 18.04 using a hybrid of two approaches found on the web. The repository installation instructions are not sufficient for 18.04.

I suspect that the method would work on derivative distributions (Mint &c.) and probably Debian itself.

There are *installation instructions* available at /g/nanovna-users/files/Nano%20VNA%20Saver/nanoVNA-H4%20software%20support%20under%20Ubuntu.pdf.

Please let me know if there are any problems with the approach.

73, Stay Safe,

Robin, G8DQX

PS: I feel your pain!

Hello,

I ordered the nanovna V2 (3GHZ) 2 weeks ago, so far I did not get it.
I would like to develop a wifi front-end to this equipment, but I have problem with compiling the source under linux mint. I got this error message during runnig the "make":
make: *** No rule to make target '.git/HEAD', needed by 'gitversion.hpp'. Stop.

Can anyone help me?

Thanks in advance!
Zoli, HG7AN

py2mta, I'd be interested in how you get on with this.

I've spent a few hours trying to get this to work on Zorin/Ubuntu with no luck.
I eventually gave in and dug out an old MS/Win laptop, (I much prefer linux)

Hi John

That is true, however we have so many new users here and those that don’t really understand the inner workings of this VNA, that a golden rule for this forum, as Dave did, is surely warranted. I would leave it up to the super users to decide when it is NOT required to

Deon, ZS6DDR.

So its better to have a few small calibrated sweeps rather than the whole spectrum?


Cheers Kev 73s MM0KJG

Dave,
I wouldn't say the wide band calibration is useless in all situations. The interpolation works pretty well when phase change vs frequency is slow, as is the case with short cables. Component tests done with short connections close the the NanoVNA itself work even interpolated from a wide calibration done at the NanoVNA connectors. Results at the end of a cable do not fare as well without a new calibration.
--John Gord

Thanks! I will do that.

Sorry guys and gals: How many times must this point be made?
?????????????

Resolution (point-to-point spacing) = Frequency Range / 101. Not
using external applications.

If you calibrate from 1 through 900 MHz, your resolution between points is
(900 - 1) / 101 = 899 MHz / 101 points = 8.9 MHz / point (or between
points). You'll miss the entire 75/80-meter, let along the rest of the ham
bands. You might get one point, randomly, within one or two bands, but the
information will be useless. With the 70-cm band spanning 430 through 450
MHz - 20 MHz wide - you might get all of 2 and at best 3 points within the
amateur 70-cm band. Still useless.

Dave - W?LEV

On Tue, Jun 2, 2020 at 3:08 PM Jim Allyn - N7JA <jim@...>
wrote:

Since the NanoVNA only has 101 point sweeps, when you calibrate from1 to
900 MHz, you have calibrated points every 8.9 MHz. So, suppose you wanted
to sweep a 7 MHz bandpass filter for a 40 meter rig you are building.
You'd miss most of the useful data. Or suppose you wanted to sweep a
narrow band crystal filter. Most likely it would be missed entirely.
Always calibrate over the frequency range you are planning to do your tests
at. You might want to try using NanoNA-Saver, which will do sweeps in
multiple segments of 101 points. I have done up to 10 thousand points and
it works well.

--
*Dave - W?LEV*
*Just Let Darwin Work*