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Anyone has or seen an sma male to an open banana binding post to connect to components ?

Paul

yes,

now go measure with your nano if you have one.

What is your name? (second time I ask)


Op 20-7-2022 om 16:08 schreef Observer:

I have found the most, mouthful fed examples on how to use a vna.
But, can the miniVNA measuring techniques be directly applied to nano ?

On Thu, Jul 14, 2022 at 07:56 PM, Ken wrote:

Be careful about suggesting using nanoVNA as an SWR Meter. Most SWR Meters are
used between a transmitter and an antenna to show the SWR in the transmission
line at an operating frequency. The nanoVNA is connected to a transmission
line and antenna to show what the SWR will be when fed from a transmitter at
various frequencies. It would lead to disaster if someone connected a nanoVNA
between a transmitter and antenna.

That's another good reason or feature of the Nano's price! If you blow it up (by transmitting into it), it probably won't break the bank. BUT if the transmitter blows up too, well then you'll wish you looked (and learned) before you jumped.

--
Doug, K8RFT

On 7/19/22 9:00 PM, Observer wrote:

Anyone has used the nano with an antenna bridge ( or noise bridge ?) to measure antenna impedances other than 50 ohms, like 300 ohms and up ?

I don't think you want to use them together. The NanoVNA directly measures impedance vs frequency. Yes, the usual display is S11 referred to 50 ohms, but you can convert that to R and X (and, in fact, it will do that for you)

No reason why it won't measure 300 ohms.

On 7/20/22 2:13 AM, Ed G8FAX wrote:

Is there a performance specification for the nanoVNA?
Particularly interested in V4.2 HW version as I have one
Kind regards

I don't know that there's published specifications - it's more "we built it, you use it, as found" There's a fair amount of lore - measurements people have made, etc.

It's kind of different from buying a VNA from, say, Keysight where they have a published spec sheet, acceptance tests, etc. That is part of what makes the FieldFox cost 100x what the NanoVNA costs.

Practically speaking, it puts out about 0 dBm, has about 60 dB dynamic range (sometimes as much as 80 dB), covers 50 kHz up to at least 900 MHz (some versions cover more), has 101,201, or 401 points in a sweep (depend on software version).

On 20/07/2022 11:14, Arie Kleingeld PA3A wrote:

I've measured in the HF range only.

Low and high impedances, testing with resistors.

The results are in the following documents:






73,

Arie

Most interesting, Arie, thanks for posting.

Judging by your plots, I'd say the 1-ohm to 470-ohms range is quite acceptable.
More complex, though for someone wanting to measure antennas!

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

I've measured in the HF range only.

Low and high impedances, testing with resistors.

The results are in the following documents:






73,

Arie

Op 20-7-2022 om 11:24 schreef David J Taylor via groups.io:

On 20/07/2022 10:19, alex wrote:

In my possible dumb imagination I would use a 10 or 20 dB attenuator to avoid mismatch on the NanoVNA side. Then measure the impedance. Then I would make an a-symmetrical attenuator from 50 to that first guess en measure again. This would only require some resistors. Or am I wrong?

73 Alex. PE1EVX

I think that would make high/low measurements much less accurate!

To the OP: As a suggestion, anything more than, say, 5 times from the nominal
50 ohms will be subject to increasing inaccuracy. Say 10 - 250 ohms you might
be OK? Perhaps someone might like to confirm this? Perhaps better if you use
a 4:1 transformer - the appropriate way round?

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Or less like 3 or 6 dB

In my possible dumb imagination I would use a 10 or 20 dB attenuator to avoid mismatch on the NanoVNA side. Then measure the impedance. Then I would make an a-symmetrical attenuator from 50 to that first guess en measure again. This would only require some resistors. Or am I wrong?

73 Alex. PE1EVX

Is there a performance specification for the nanoVNA?

Particularly interested in V4.2 HW version as I have one

Kind regards

Ed G8FAX

You won't need it. The nano measures it all.

What's your name?

Op 20-7-2022 om 10:34 schreef Observer:

yep, I am experimenting with hf antennas, with unknown, or predicted high z or very low z

Are you going to use one?

Op 20-7-2022 om 06:00 schreef Observer:

Anyone has used the nano with an antenna bridge ( or noise bridge ?) to measure antenna impedances other than 50 ohms, like 300 ohms and up ?

hate Youtube !
Often, they dont get to the point, waste time on bla bla, to incease the time

Concerning your filter, note that:

nanoVNA makes its measurements with an internal 50 ? impedance generator. When you use this filter behind a PA, fortunately, its internal impedance is not 50 ?; otherwise the yield would be catastrophic. This difference greatly changes the transfer function of the filter.

On the other hand, when you measure the S11 at the input of the filter, the latter being charged at the output by 50 ?, the measurement is correct.
--
F1AMM Fran?ois

Yes, and if you want to fool with Python, scikit-rf has a whole set of tools to work with all
the different representations, plot them, convert back and forth, and even do a variety of
VNA calibrations.

Thanks for the explanation on the basic operation of the nanaoVNA bridge. It must not be easy to measure the phase!

Unfortunately, I don't know Python. I'm just getting by in C and C#.

For the conversion formulas, I struggled a bit but I restored them as well as the reciprocal formulas. This is how I realized that, concerning the Smith diagram, in fact, if an orthonormal reference mark is passed through the center of the abacus, it is in fact graduated in parameter S11. The real part is on the horizontal axis the imaginary part is on the vertical axis. I have never read that in the literature.

For amateurs put off, a priori, by the Smithn abacus, I would repeat to them that we no longer use this abacus to make graphic calculations. Moreover, these calculations were only made at a fixed frequency (a single frequency). Currently, as for the nanaoVNA and nanovna-saver, it is a means of presenting the parameters according to the frequency. The curve that we see on the Smith only exists because the frequency varies. Fortunately, there are markers to know to what frequency a point on the curve corresponds.

The .S1p files are ASCII files where each S11 parameter is saved, corresponding to each measurement, at a different frequency. Change the .S1p extension to .txt and notepad will easily open the file for you.
-----
# HZ S RI R 50
100000 -0.9837865399025408 0.1942964059291501
109812 -0.9820312153958951 0.21310478092053914
[...]
-----
If you display (chart) in Excel, you will find the curve that appears on the Smith diagram. It's actually very educational to understand the interest of the "Smith" representation.
--
F1AMM Fran?ois