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Re: quick measuring cable characteristic wave resistance

 

On Thu, Dec 26, 2019 at 08:33 AM, DJ7BA wrote:


the Lambda/8 method:
Do you have any citations for this method?


Re: Brief NanoVNA-H vs NanoVNA_F comparison #nanovna-f

 

On Fri, Dec 27, 2019 at 02:42 AM, David J Taylor wrote:

You might like to post questions about the NanoVNA-F in its own group:
I'm sure the developers would appreciate your suggestion for new firmware features and extended frequency range. I expect many users would appreciate
these features!
==================================================================================

Hi David,
After Dr. Kirby was banned by the NanoVNA-F group's owner for expressing negative opinions about the connectors used on the Demo board , I try to only offer assistance to other user's on that group. This group is by users for users and freely accepts the exchange of ideas. When a group is created by a retailer, as is the NanoVNA-F group, it can tend to be less receptive to any perceived criticism of its product. Dr. Kirby was eventually re-instated after other members complained about the quick yank, but the initial response was to me un-democratic.

Hopefully the NanoVNA-F's production team will start pouring more of its resources into fulfilling its promises on the software and firmware side. We all want to see products like the NanoVNA-F become successful, but we also want to see continued after market contributions such as hugen has done with the NanoVNA-H. So far I've seen words, but not action.

Happy holidays.

- Herb


Re: errors of "error" models

 

#95.5: [SOLVED] : The "Mystery" of the Identical Results Using Different VNAs

Hello,

Allow us, please, to announce that in the sequence of our three guesses in time :
"Moebius" [#95.1], "Hardware" [#95.3] , and "dB" [#95.4], the very first of them is
fulfilled : "Moebius" - the details are following.

Sincerely,

gin&pez@arg

[#95.1] : On a Sufficient Condition for Identical Measurements Using Two Different VNAs
26 December 2019 - /g/nanovna-users/message/8657

[#95.3] : On the Sufficient Conditions for Identical Measurements Using
Two Substantially Different VNAs - Our Research has been Completed
27 December 2019 - /g/nanovna-users/message/8669

[#95.4] : On the Analogy of Difference of Ratios but not of Ratios
27 December 2019 - /g/nanovna-users/message/8674

:#95.5


Re: nanovna cases #enclosure

 

Maybe you can share with us some files that one can convert to .stl to 3D
print?

I like the case very much.

Cheers!


73 de Luis, CT2FZI



<>
<>

On Fri, 27 Dec 2019 at 00:39, Gigabyte <steven.b.hoff@...> wrote:

That case looks really nice. Looks like it will keep a lot more dirt and
grime out of the NanoVNA. Looking forward to hearing a price on them I'd be
interested if the price isn't too high.




Re: Brief NanoVNA-H vs NanoVNA_F comparison #nanovna-f

 

Herb,

You might like to post questions about the NanoVNA-F in its own group:

/g/nanovna-f

I'm sure the developers would appreciate your suggestion for new firmware features and extended frequency range. I expect many users would appreciate these features!

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


Re: Plate RF Choke Measurements #measurement

 

Hi Ady.

I only did a screen capture. The measurement and cal are one port only. So I would have only S11 data available.

The main thrust of the post is you need to capture a reasonable number of data points, 10 bands for 100 kHz to 30 MHz was used. You can probably get by with much less. Perhaps 401. The series loops appear with no added short applied. The choke is measured in place on the chassis. Take care with this placement if you are concerned about a problematic loop near an operating band!

A one port measurement appears sufficient.

I can capture a S data file. Might be of interest if you desire some other form of display or post processing. Although this is all very nice, I am not parting with my GDO!

Alan


Re: Plate RF Choke Measurements #measurement

 

Dear Alan,

thank you for sharing the measurements. I assume you used NanoVNA-saver.
Can you please share the s1p or s2p files if saved?

TNX, 73 Ady YO2NAA

On Fri, Dec 27, 2019 at 5:14 AM alan victor <avictor73@...> wrote:

Re visit this topic as I am looking at plate chokes for a tube amplifier.

I used 1010 points from 100 kHz to 30 MHz. There are 3 chokes shown here.
The older National R175 shown in a prior post with its problems of 2 in
band resonant conditions, a 230 uH homebrew choke for 160 - to - 40 meter.
Fine but horrible beyond 15 MHz and finally a fairly nice choke at 100 uH
on a ceramic core complete with a 500 pF/20 kV bypass capacitor. This choke
shows a single resonance but is out of band.

It appears unnecessary to provide a short across the choke to pick up
these loops if a shunt S11 measurement is used. In all cases the parallel
resonate point crosses the open circuit side of the chart. A short across
the choke simply rotates the reflection towards the short circuit side of
the chart however the series loops stay in tact.

Alan




Plate RF Choke Measurements #measurement

 

Re visit this topic as I am looking at plate chokes for a tube amplifier.

I used 1010 points from 100 kHz to 30 MHz. There are 3 chokes shown here. The older National R175 shown in a prior post with its problems of 2 in band resonant conditions, a 230 uH homebrew choke for 160 - to - 40 meter. Fine but horrible beyond 15 MHz and finally a fairly nice choke at 100 uH on a ceramic core complete with a 500 pF/20 kV bypass capacitor. This choke shows a single resonance but is out of band.

It appears unnecessary to provide a short across the choke to pick up these loops if a shunt S11 measurement is used. In all cases the parallel resonate point crosses the open circuit side of the chart. A short across the choke simply rotates the reflection towards the short circuit side of the chart however the series loops stay in tact.

Alan


Re: errors of "error" models

 

#95.4: On the Analogy of Difference of Ratios but not of Ratios

Hello,

- - - - - - - - - (c) gin&pez@arg (cc-by-4.0) 2019 : start - - - - - - -
This may be the result of measuring only levels and of measurements
only in dB.
- - - - - - - - - finish : (c) gin&pez@arg (cc-by-4.0) 2019 - - - - - -

Sincerely,

gin&pez@arg

:#95.4


Re: nanovna cases #enclosure

 

That case looks really nice. Looks like it will keep a lot more dirt and grime out of the NanoVNA. Looking forward to hearing a price on them I'd be interested if the price isn't too high.


Re: nanovna cases #enclosure

 

And before anybody says it... what else is boxing day for?? LOL!


Re: Can the nanoVNA be used as a scalar spectrum analyzer ?

Vince Vielhaber
 

Set your frequency source for 9.804 MHz and see if it shows up.

Vince - K8ZW.

On 12/26/2019 05:36 PM, Alberto I2PHD wrote:
On 2019-12-26 21:07, David Eckhardt wrote:
For example, the SWR plot is scalar - no sign or complex portion
involved.
Use the the analyzer's own frequency source, Channel 00, and inspect
Channel 01 response. Ignore the sign. You have a scalar analyzer. Of
course, no Smith Chart.
Thanks Dave, and all the others who answered.

Well, I don't need to use the nano as a scalar spectrum analyzer, for
this I already have a Rigol.
I was just puzzled by the fact that moving the generator output by 100
kHz the displayed signal
did disappear. But now that I have been remembered that only 101 points
are scanned, everything
is clear.

Many tanks indeed,
--
K8ZW


nanovna cases #enclosure

 

Just knocked up a case this afternoon in the mancave.
This case uses the existing screws in the nanovna, so should be easy to pop together
like a six piece jigsaw :-)
Acrylic/polycarbonate cut with CNC..
If there is any interest i can polish design..flatpack post.. price tba.
Will get round to doing a desktop box version shortly display and sma's on the front
usb/c on the rear, will post pictures when finished.


Re: errors of "error" models

 

#95.3: On the Sufficient Conditions for Identical Measurements Using
Two Substantially Different VNAs - Our Research has been Completed

Hello,

- - - - - - (c) gin&pez@arg (cc-by-4.0) 2019 : start - - - - - -

Since any of the 6 involved differences into G-mini:

G = (g-l)*(o-s)/[(g-o)*(s-l)-(g-s)*(l-o)]

is of the form (g2-g1), it seems that the even simpler
sufficient condition for Identical Measurements:

g" = k*g' => (g"2-g"1)/(g'2-g'1) = (k*g'2-k*g'1)/(g'2-g'1)
= k*(g'2-g'1)/(g'2-g'1) = k

which theoretically results to the previous one [#95], may
also be proved in practice as an adequate one for Identical
Measurements, we check both conditions at those 8 frequencies
on which we simultaneously have the following available results
for both [NanoVNA] and [HP 8505A]:

I/II. The 6 Ratios of Differences:

Modulus:

- we don't post images - we only post links to them -

Argument:


Conclusion: * A d e q u a t e *

II/II. The 4 Ratios:

Modulus:


Argument:


Conclusion : * I n a d e q u a t e *

- - - finish : (c) gin&pez@arg (cc-by-4.0) 2019 - - - - - - - - - -

Well, this is very Interesting, indeed. But it seems that, if someone is more
interested on this, then he has to somehow dive rather deeply down to the
technicalities of the hardware implementation. However, this is definitely not
a subject for The Common User - like us. Therefore, we consider that our
research on this subject has been also completed.

Sincerely,

gin&pez@arg

[#95]: On a Sufficient Condition for Identical Measurements Using Two Different VNAs:
26 December 2019 - /g/nanovna-users/message/8654

:#95.3


Re: Can the nanoVNA be used as a scalar spectrum analyzer ?

 

On 2019-12-26 21:07, David Eckhardt wrote:
For example, the SWR plot is scalar - no sign or complex portion involved.
Use the the analyzer's own frequency source, Channel 00, and inspect
Channel 01 response. Ignore the sign. You have a scalar analyzer. Of
course, no Smith Chart.
Thanks Dave, and all the others who answered.

Well, I don't need to use the nano as a scalar spectrum analyzer, for this I already have a Rigol.
I was just puzzled by the fact that moving the generator output by 100 kHz the displayed signal
did disappear. But now that I have been remembered that only 101 points are scanned, everything
is clear.

Many tanks indeed,

--
/*73 Alberto I2PHD*
<<< >>>/


Re: NanoVNA-Saver 0.2.1 serial connection on Ubuntu 16.04 won't connect

 

49jhanl@... wrote:
My NanoVNA-Saver app. on Ubuntu 16.04 identifies /dev/ttyACM0 as the serial connection, but it does not appear to connect. Same NanoVNA runs fine on Win 10. Is this a permission >problem, and if so, how do I fix it.
Usually caused by not being in the group which owns the tty ports (including the USB ones).

Add your username to the dialout group. Since it's that ridiculous pseudo-security kludge the Ubuntu people like to tout, you must use sudo. Or just log in as root, and drop the sudo part below:

sudo usermod -a -G dialout $USER

substituting your username for "$USER" of course.

Or go the the /etc directory, open your favourite text editor (Mine is Joe, but I cut my word-processing teeth back in the WordStar on CPM days.) and modify then save the group file, putting your username at the end of the dialout group line. Log out and back in for the changes to take effect.

--
Wes Will
N9KDY


Re: NanoVNA-Saver 0.2.1 serial connection on Ubuntu 16.04 won't connect

 

It Is a permission thing with the port.
I had the same problem. But I can't find the answer by :
Searching my mail
Searching the forum's mail
Searching the web
Searching my desk for where I wrote it down
I wish I could help
It may be the New Moon or the eclipse.?
None of my searches worked.

On Thu, Dec 26, 2019, 12:07 PM <49jhanl@...> wrote:

My NanoVNA-Saver app. on Ubuntu 16.04 identifies /dev/ttyACM0 as the
serial connection, but it does not appear to connect. Same NanoVNA runs
fine on Win 10. Is this a permission problem, and if so, how do I fix it.

Thank you




Re: Can the nanoVNA be used as a scalar spectrum analyzer ?

 


Re: First PCB pictures of the V2

 

Hi Gabriel, you are telling us a good news about the new VNA. I want to know the final price of the VNA, whether it has a case?


NanoVNA-Saver 0.2.1 serial connection on Ubuntu 16.04 won't connect

 

My NanoVNA-Saver app. on Ubuntu 16.04 identifies /dev/ttyACM0 as the serial connection, but it does not appear to connect. Same NanoVNA runs fine on Win 10. Is this a permission problem, and if so, how do I fix it.

Thank you