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Hello guys,
I’m extensively playing with my Nano..
Could anybody help me to understand the phase curve?
It’s clear that is shows resonance point when there is rapid change in phase (almost vertical line) but I can’t understand where the angle is measured... Why it is somehow related to 90dg (remark in the marker line)?
The value are from 0 to 180 and from 0 to -180dg... where is the vector start point?
I can’t imagine the vector in the Schmidt diagram... Could you lead me to some document or tutorial to get the point?
Thanks Stepan

I agree as well; the ability to work with 5.8Ghz / 3.6Ghz gear is pretty important to me and I assume would gather a lot more interest from WISPs (and other related commercial /hobby interests). The RF hacking community is really exploding lately as well.

If 6Ghz could be done decently for anywhere near $150 or sub $200, that would be unbeatable. I'm pretty sure 5.8 is where you will pick up a lot more interest from a much wider audience, rather than "just us hams".

I personally will be waiting for that magic 5.8Ghz capability, before my next inexpensive VNA purchase. I wonder if we could get one of the larger RF related youtube channels to do some public polling on this..

-
Thank you,
Gus Osborne
KI4WYY


-
Thanks!
Gus Osborne
Assurance Technology, LLP

The problem with measuring crystals is that the nano does not have small enough frequency increments to characterize such a high Q device.
What I did was connect the crystal from the first port to ground but it amounts to almost the same thing.? The Smith chart shows a loop around the crystal resonance and you can walk the marker around the loop to find the resonant frequency.? This only works nicely for low Q crystals.? I had one crystal of such high Q that the nano was unable to hit its resonance.
Bob On Thursday, February 6, 2020, 08:52:49 AM PST, aparent1/kb1gmx <kb1gmx@...> wrote:

TO get 1hz resolution with 101 points you need very narrow sweeps
so VNA-saver is likely the tool to do that.

Even with 10hz that only 1000hz sweep and likely not wide enough.

Also if you sweep too fast the crystal will ring and you get a tilted
result.

Without using software to splice multiple sweeps its a battle of
precision and number of possible points.

Even with a big? VNA/PNA a lot of points (4096) at 1hz resolution
and a slow sweep (at least 40mS per point) was needed.

Allison
-----------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

Yes..it has blue PCB with version marking as nanovna- h v3.3
Thank you very much for clarifying...

Exactly my thoughts Bob! A 6GHz capable unit is high on my priority list for the same reasons.

73,
Randy
NC8U

There is lots of discussion in this thread about what the market is.

I understand there is a calculus regarding cost vs how units will sell and there exists a perception of what the community wants these for.

I am a ham and an ARES member, and the group that serves my county is interested in setting up a high speed Mesh Radio data network. My perception is this particular desire amounts to a world wide movement.

Within the hobby, the technologies are referred to as High Speed Multimedia (HSMM), Broadband Hamnet (BBHN), Amateur Radio Emergency Data Network (AREDN) and others.
There are also groups, not necessarily hams, setting up networks entirely within the confines of ISM unlicensed operations.

As such, the equipment used are consumer grade hackable WIFI access points, brick amplifiers, filters, commercial antennas, and the like. The bands of operation range from 70cm to 5cm, with the bulk of equipment being used operating at 2.4, 3.4, or 5.8 GHz. This is, in my opinion, is the Amateur market for a lower cost 6 GHz capable VNA, and my own primary interest in owning such as this.

While it may be true that the mesh radio experimentors are largely a plug and play crowd who dont build much from scratch and buy their antennas, sadly there is alot of junk on the market, or antennas being marketed with exuberantly exaggerated specifications, or shipped with manufacturing defects and an instrument to confirm performance would be a game changer. It is my belief that microwave experimentors of this class may be very receptive.

73;
Bob KV4PC

Hi Herb

Thank you for the comment. I like you sense of humor ?

Kind regards

Kurt



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af hwalker
Sendt: 1. februar 2020 03:16
Til: [email protected]
Emne: Re: [nanovna-users] #nanovna-h4 stops at boot screen

TO get 1hz resolution with 101 points you need very narrow sweeps
so VNA-saver is likely the tool to do that.

Even with 10hz that only 1000hz sweep and likely not wide enough.

Also if you sweep too fast the crystal will ring and you get a tilted
result.

Without using software to splice multiple sweeps its a battle of
precision and number of possible points.

Even with a big VNA/PNA a lot of points (4096) at 1hz resolution
and a slow sweep (at least 40mS per point) was needed.

Allison
-----------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

I use this formula for the motional capacitance:

Cm = (f1 - f2)/(2*PI*f1*f2*Rt)

Where f1 and f2 are the upper and lower 3 dB points, so you could just say
BW for f1 - f2.

In the denominator, f1*f2 is not far from fc^2 where fc is the resonant
frequency of the crystal so you can use fc^2 if you like.

Rt is the total resistance of the circuit. So assuming you have a 50 ohm
generator plus 50 ohm detector and you measured the loss resistance of the
crystal at resonance at 55 ohms, your value is 155 ohms.

Having found Cm, Lm is the value of inductance that has the same reactance
as Cm at the resonant frequency. But a formula for that is:

Lm = 1/(4 * PI^2 *f^2 * Cm)

Where f is just the resonant frequency of the crystal.

You'll probably wind up with Cm in femtofarads and Lm in millihenries.

All of this depends of the resolution of the VNA. Being able to get down to
1 Hz resolution can help. I tried one crystal and didn't think I got good
results. But in the nanoVNA notes by Wes Hayward linked here recently, he
seemed to get some good crystal measurements. And Hayward is the guru of
crystal measurements although he wasn't deriving motional parameters in his
paper.

In doing crystal measurements, people often use transformers or resistive
pads to put the crystal in a 12.5 ohm environment, meaning the crystal sees
12.5 ohms looking in either direction. I'm not sure how advantageous this
is, but it does lower the BW and so would seem to make fine resolution even
more important.

For parallel capacitance, generally using a low frequency capacitance meter
like the AADE or eBay clones works.


73-

Nick Kennedy, WA5BDU

Oristo and Alan,

When I started I thought this was a problem in both VNAs. But, you are right. I will post it on the other group.

There remains an issue with nanoVNA-Saver and how it treats a response of 0.0 + j0.0 from an S21 measurement of a VNA.

Thanks for your help.

--
Bryan, WA5VAH

Hi all,
I wonder which is the correct procedure for testing a Crystal quartz.
Nano VNA has 0.6.0 firmware version and on PC NanoVNA Saver 0.2.2-1 is running .

A bit naively after calibration in the range 50 KHz - 60 MHz , I just connected output and input ports through a 10 MHz crystal to explore its characteristics, mainly serial R and Quality Factor .

Graphical results seems fair but calculated value in nanoVNA Saver are a bit odd:

Impedance = 55.32 - j3.7 ohm
Quality factor: 0.067

In additon i tried to run from nanoVNA Saver an analysis handling the filter as a pass band and got this time a Quality factor: 54924.73 - a bit higher but anyway very far away from typical quartz Q. The corresponding bandwidth at -3dB was 1.82 KHz.

Sorry was not able imbedding images in mail body, you can see them in the attached images.rtf file.

Any hint is appreciated ?

Stefano, I3VBP

I am not familiar with the F model details. As Oristo states, try the post there. However, it sounds like the root cause of the problem is up setting the calibration. Or resetting the cal to the point it is lost.

Reading this thread about market, sales, prices and specs.

I'm a radio amateur who appreciates good equipment. What I see at several radioclubs in the Netherlands (EU) is that the low priced nanoVNA is extremely popular. Most of the guys that buy them do antenna measurements or just want to explore this instrument (low cost), even if they own the good ol' MFJ antenna analyzer

Only a few of those guys are interested in the world above 1 GHz.

And for myself?
HF man all the way. 80 or 90dB of dynamic range for working on the bandfilters? Wonderful and enough (better than my miniVNA).
Have a good look at my antennas? Great!
Smithchart? Need to have for me, but I spend a lot of time explaining the thing to fellow hams. They are mostly interested in SWR and sometimes will look at a bandfilter.

It seems that the small nanoVNA-H has taken a big part of the hamradio-analyzermarket here (pricepoint under $50). The slower adaptors will probably choose an H-4 now.

(My $0,02)

Arie PA3A

Gentlemen, this topic has nothing to do with the title. Please open a new theme, this is not a firmware specialty theme.

thanks, Gyula HA3HZ

Hello

The Output Multisynth Divider (OMD) in the Si5351A has a minimum division of 4, see the datasheet reg. 44 and +8 for the others. The use at 300 MHz, well above 200 MHz, is out of spec. But like many other components it will still work out of spec - but it depends. If we are only talking about a distinct output frequency the closer you get to 300 MHz the less certain you can be that it will work. Please see this message: /g/nanovna-users/message/3285 If I were to put my money on it I would say that the max fout is 280 MHz. If it works on 300 MHz I would say that it is a lucky punch. So 270 MHz is a safe and good S/N choice.

Unless the sweep is very narrow I doubt there is a need for the OMDs to run in fractional mode. The two LOs have to track with the IF distance but even if they are a few Hz apart I don't think this will have any impact on the measurement. Here is a tutorial about the math in the Si5351A:

Bo
www.rudius.net/oz2m :: www.rfzero.net

Did I miss anything?

Yes, you posted this in the wrong group.
Instead, try one of these: /g/nanovna-users/wiki/home#nanoVNA-F

Hi Bryan,
thanks for pinging me - I'll get on it as soon as things quiet down a
little more here at work. Should be able to look at it later today
or tomorrow :-)

--
Rune / 5Q5R

On Thu, 6 Feb 2020 at 06:41, Bryan, WA5VAH via Groups.Io <bryburns=
[email protected]> wrote:

Rune,

Could you check the sequence of posts at
/g/nanovna-users/message/10627. There seems to be an
issue with nanoVNA-Saver that should be easily fixed.

Thanks
--
Bryan, WA5VAH

Rune,

Could you check the sequence of posts at /g/nanovna-users/message/10627. There seems to be an issue with nanoVNA-Saver that should be easily fixed.

Thanks
--
Bryan, WA5VAH

Alan,

I re-calibrated the nanoVNA-F with a single load on PORT2 for the isolation calibration. I have been looking at the nanoVNA-F response with both ports terminated in 50-ohm loads for several minutes now and there have been no indications of a 0.0 + j0.0 response in the nanoVNA-F. Does this indicate success?

There is an option to turn off the calibration correction under the menu "CAL"->"CORRECTION". So I turned that off with a 50-ohm load connected to PORT1 and PORT2. The 0+j0 indications in S21 started immediately. In fact, the indications of 0.0 + j0.0 in S21 occasionally extend out to 35 MHz, well beyond my previous observation of about 10 MHz as the maximum frequency. Perhaps someone more knowledgeable of the firmware can tell me what that option does in the nanoVNA-F firmware.

Suspicious that I had done something wrong, I went back and performed another complete calibration scanning from 50 kHz to 50.05 MHz on the nanoVNA-F. This time I watched far more carefully what the nanoVNA-F was indicating at all of the steps. Things seemed normal for the open and short; however, in the load configuration I noticed there were a lot of 0.0 + j0.0 indications in S21 logmag data at many frequencies up to about 35 MHz. How does this impact calibration of the load? I assume that it does not. For the isolation calibration I used only a single load on PORT2 and left PORT1 open. I did not see any indications of 0.0 + j0.0 in the scans for isolation in the S21 data during this calibration step. I then saved the calibration in C4. I then attached loads to PORT1 and PORT2 and have not seen any indications of 0.0 + j0.0 since. When I turn off "CAL"->"CORRECTION" I immediately see many frequencies with an indication of -INF dB on the display which I am sure are specifically related to getting 0.0 + j0.0 from the VNA hardware. The indications on the left side of the screen go to "D R S T X" and "C4" disappears until I click again on "CORRECTION." Turning on the "CORRECTION" causes the indications of 0.0 + j0.0 in the S21 data to disappear.

Do you know if the drive level in the device is changed in any way during a calibration? What would cause the issues in S21 when a load is applied to PORT1 during "LOAD" or "THRU" calibration? The S21 data is not needed for calibration of the load so the fact that S21 is so small is irrelevant to load calibration; however, PORT1 termination could be very relevant to S21 "ISOL" calibration.

So I tried calibration again, this time I tried to be very careful to list every step as thoroughly as I can to make sure I am not missing something.

With a good cal in C4 and "CORRECTION" on I did the following in sequence within the "CAL" menu: 1) clicked "CORRECTION", 2) clicked "RESET", 3) clicked "CALIBRATE", 4) opened PORT1, 5) after several scans clicked "OPEN", 6) applied a short to PORT1, 6) after several scans clicked "SHORT", 7) removed short and installed 50-ohm calibration load on PORT1, 8) after several scans I clicked on "LOAD", 9) disconnected the calibration 50-ohm load from PORT1 and connected it to the previously open PORT2, 10) after several scans (there were no indications of 0.0 + j0.0 in S21) I clicked on "ISOLN", 11) I then added a 50-ohm load at PORT1 (50-ohm loads on both PORT1 and PORT2) after which there were numerous indications of 0.0 + j 0.0 on the screen; however, I did not click on anything on the VNA in this configuration, 12) I then replaced both loads with a RG316 through cable that is 6" long going from PORT1 to PORT2. (I know this is not completely correct because I did not use any cables for the previous steps but for purposes of getting a decent S21 magnitude thru cal it should be good enough. 13) I then clicked on "THRU", 14) clicked on "DONE", 15) indication on left of display was C* D R S T X", 16) clicked on "SAVE 4" 17) indication on left of display changed to "C4 D R S T X", 18) removed 6" through cable and replaced it with 2 loads, 19) now there are no indications of 0.0 + j 0.0 for S21 appearing on the display. S21 Isolation with loads on both PORT1 and PORT2 run from about -81 dB to about -105 dB. 20) If I go back to "CAL" and turn off "CORRECTION" the left side of the display indicates "D R S T X" as it should. But, the indications of 0.0 + j0.0 in S21 measurements starts immediately on numerous frequencies below about 30-35 MHz. But with correction enabled, I never see this indication. Why?

Did I miss anything?

Notice that in Step 10 when I experimented with putting a load on both PORT1 and PORT2 that I get numerous 0.0 + j0.0 indications with a load on PORT1 and PORT2 but no such indications when a load is applied only to PORT2. I have seen several folks indicate that it is best to put loads on both PORT1 and PORT2 for the isolation test. In fact that is in Rune's recommendations in nanoVNA-Saver. My experience, here, seems to indicate that when the signal out of PORT1 is absorbed in a load that the isolation at PORT2 is improved enough to cause 0.0 + j0.0 values in S21 at low frequencies. I don't think this is too surprising but it does indicate some cross-talk between PORT1 and PORT2 is occurring at lower frequencies at a very low level.

Should I just use the calibration in the device where only a single load is applied during isolation calibration? At the moment, that is what I am thinking of doing.

I appreciate your patience in reading through all of this.

--
Bryan, WA5VAH

Alan,

Great measurement. It is pretty clear that your VNA is not having the issue that I am seeing.

--
Bryan, WA5VAH