¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. Nanovna-Users
  2. Messages
Expanded Topics Messages
Date
Re: Setting up additional networks to achieve 50 ohm impedance matching #design #measurement #filtering #calibration #adapters

 

On Fri, Oct 30, 2020 at 12:03 AM, alan victor wrote:

I designed a 10 7 MHz AM filter and terminated it with the design value of 300
ohms and then with 50 ohms on one side. The response of course changes but the
filter works as expected as a BPF.

So yes, the cost of doing it correctly just makes no sense for a demo card.

See attached pictures.
Would you please tell me how to get those two plots? :-)

Thanks!

A.
File /NanoVNA PC Software/NanoVNA-App.rar uploaded #file-notice

[email protected] Notification
 

The following files have been uploaded to the Files area of the [email protected] group.

By: OneOfEleven

Description:
NanoVNA-App PC software v1.1.101 currently only for NanoVNA V1's
Re: Setting up additional networks to achieve 50 ohm impedance matching #design #measurement #filtering #calibration #adapters

 

On Thu, Oct 29, 2020 at 11:35 PM, John Gord wrote:
I think you are correct: Presumably the designer did not want to go to
the expense and effort to do a good "L" match, and found that the combination
of resistive input matching and no output matching gave acceptable results.
Meanwhile, I had a look at my board and I found the "0 ohm" resistor might be the only component I can see on the output part - I didn't expect such a resistor could exist.
That would mean I can replace it to set up a network using the pads available on the PCB.


It is also possible that the intent was to demonstrate that for most
passive circuits, S21=S12, but S11 does not necessarily equal S22. You should
be able to see this by reversing the connections: Forward and reverse
transmission should look about the same, but the input impedance will look
quite different.
Nice prompt, thanks! I was not thinking of the ceramic filter as a symmetric element.

I'm starting to have fun. :-)

A.
Re: Serial protocol struggle

 

Wow ?Thank you 1 of?11 it's already makes sense !
Rather exciting now !

*Sent:* Thursday, October 29, 2020 at 4:01 PM
*From:* "OneOfEleven" <cmoss296@...>
*To:* [email protected]
*Subject:* Re: [nanovna-users] Serial protocol struggle
The NanoVNA-V2 is not a text serial protocol, it's purely binary ..

Go to "Protocol description" here ..



NanoVNA V1's are text protocol with some binary options if desired.
Re: Setting up additional networks to achieve 50 ohm impedance matching #design #measurement #filtering #calibration #adapters

 

I designed a 10 7 MHz AM filter and terminated it with the design value of 300 ohms and then with 50 ohms on one side. The response of course changes but the filter works as expected as a BPF.

So yes, the cost of doing it correctly just makes no sense for a demo card.

See attached pictures.

Alan

10.7_300.jpg
10.7_50.jpg

Re: Serial protocol struggle

 

The NanoVNA-V2 is not a text serial protocol, it's purely binary ..

Go to "Protocol description" here ..



NanoVNA V1's are text protocol with some binary options if desired.
Serial protocol struggle

 

Hello and great questions I haven't considered all that before in the past when I wrote freeware
I just released it as freeware closed source.? You can see some on WB9RAA.com ( ) or 1CNC.xyz

But okay in this case since I will make it an open source project under MIT license
using?C# will be Windows only application compiled under Visual Studio 2015.
Might even make some simple Python to amCharts plotting too. Easy to start that way.

Right now my struggle is I'm trying to send serial data to the comports and
I only received the digit "2" 32 hex no matter what I send to it. Baud rate does not
seem to matter. I tried this under Win10 x64 *COM3* and under
OSX 10.10.5 */dev/cu.usbmodemDEM1*

Both VNA_qt apps run as expected on Windows and OS X.

Looking thru the source code I have not seen any obvious commands that seem to match the Serial documentations. I assumed
this is an ASCII protocol but now not so sure.

I've been trying com ports SPY programs with no luck to capture what the VNAqt's send to the device. My
NanoVNA SAAN2 goes into the black screen with? white large text

*NanoVNA V2_2*
*USB MODE*

when I open Windows putty or OS X CoolTerm or ZTerm serial comm apps

Any help getting this off the ground at square one would be beneficial !!!

I'm thinking the first app would be just plotting SWR across the user? selected
Ham Bands? much like I did for the RigExperts AA30.Zero years ago.

Thank you guys

Ed March

*Sent:* Thursday, October 29, 2020 at 3:00 PM
*From:* "Jim Allyn - N7JA" <jim@...>
*To:* [email protected]
*Subject:* Re: [nanovna-users] nanoVNC -h
On Thu, Oct 29, 2020 at 08:08 AM, Ed March wrote:

Looking forward to writing my ham c#
App to talk to the serial port
What operating systems will be supported?

I will make it freeware when finished.
There is no universally accepted definition of freeware, so freeware doesn't tell us anything other than there will be no monetary cost for it. (Maybe.) Will the source code be released under the GNU General Public License or other free/libre/open source license?



Will users have the Four Freedoms?

0) The freedom to run the program as you wish, for any purpose (freedom 0).
1) The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this.
2) The freedom to redistribute copies so you can help your neighbor (freedom 2).
3) The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.
Re: Setting up additional networks to achieve 50 ohm impedance matching #design #measurement #filtering #calibration #adapters

 

On Thu, Oct 29, 2020 at 04:03 PM, alan victor wrote:

I agree John.

At best my schematic is a circuit rendering.
Maybe the data sheet has info on the required terminations.
I had a look a the corresponding datasheets, so far I found two manufacturers. I attach the one by ECS.
The inductor between input and output looks like an extra component required for the operation of the filter.
I wonder why anyway the value for the ECS case is 15 pH, in another datasheet, by Token, it's 15 uH, and in the circuit of my test board is 4.7 uH.

A.

trap.png

Re: Setting up additional networks to achieve 50 ohm impedance matching #design #measurement #filtering #calibration #adapters

 

Andrea,

I think you are correct: Presumably the designer did not want to go to the expense and effort to do a good "L" match, and found that the combination of resistive input matching and no output matching gave acceptable results.
It is also possible that the intent was to demonstrate that for most passive circuits, S21=S12, but S11 does not necessarily equal S22. You should be able to see this by reversing the connections: Forward and reverse transmission should look about the same, but the input impedance will look quite different.

--John Gord

On Thu, Oct 29, 2020 at 02:53 PM, Andrea IK0RNT wrote:


John,
I had downloaded the datasheets, so eventually for the 10.7 MHz filter the
value of about 300 ohm for input and output impedance was sure.
I was kind of asking for confirmation about the role of the input resistive
network. What it is still not clear to me is why the designer considered
matching the input impedance as necessary, and, instead, he tolerated a direct
connection of the output to an unmatched load (the NanoVNA). Maybe for the
output he gave up since other resistors would make the signal too weak and he
didn't mean to use capacitors or inductances for some reason?

A.

On Thu, Oct 29, 2020 at 02:09 AM, John Gord wrote:
Andrea,
I am not familiar with the band reject filter in circuit 5, but the filter
in
circuit 6 is probably a fairly standard 10.7 MHz ceramic bandpass filter
once
common in FM receivers. These filters are usually designed to work best
with
a source impedance of 330 ohms and a load impedance of 330 ohms. Circuit 6
provides a load of 50 ohms to the source generator and a source impedance of
about 325 ohms to the filter (at the expense of loss in the resistors). The
load impedance presented to the filter is just the 50 ohms of the VNA port
(since they didn't use R7 and R11). The matching for the filter would have
been better with R7 and R11 at 300 ohms and 51 ohms, but I assume that they
were not used because the circuit as built is "good enough", and skipping
the
resistive matching components gives a larger (if less properly filtered)
signal at the output.
--John Gord

On Wed, Oct 28, 2020 at 04:48 PM, Andrea IK0RNT wrote:


On Thu, Oct 29, 2020 at 12:40 AM, Andrea IK0RNT wrote:
Reading that to achieve the goal of maximum power transfer from a source
to
a
load just resistors could be used was definitely illuminating. Of
course,
power waste in resistors would be an outstanding undesirable aspect. But
considering this chance I may finally understand what the designer of
the
circuits 5 and 6 in the scrap I attach again - I still wonder what L1 is
for
in circuit 5, but I can wait to figure out this.
I'm sorry, I forgot to attach... :-(

A.
Re: GetsScreenSE #applications

 

I need the firmware. please send to my email thank you
Pada tanggal 30 Okt 2020 04:27, "Christian Zietz" <czietz@...> menulis:

Nice small tool. Thank you! However, screenshots saved from my NanoVNA H
(2.8" version) exhibit a dark blue shadow, for example next to the letters
on the left hand side showing the calibration status. See attached file.
This does not appear on screenshots taken with NanoVNA-Saver; so it's not a
firmware issue.

Regards
Christian
Re: nanoVNC -h

 

On Thu, Oct 29, 2020 at 08:08 AM, Ed March wrote:

Looking forward to writing my ham c#
App to talk to the serial port
What operating systems will be supported?

I will make it freeware when finished.
There is no universally accepted definition of freeware, so freeware doesn't tell us anything other than there will be no monetary cost for it. (Maybe.) Will the source code be released under the GNU General Public License or other free/libre/open source license?



Will users have the Four Freedoms?

0) The freedom to run the program as you wish, for any purpose (freedom 0).
1) The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this.
2) The freedom to redistribute copies so you can help your neighbor (freedom 2).
3) The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.
Re: Setting up additional networks to achieve 50 ohm impedance matching #design #measurement #filtering #calibration #adapters

 

John,
I had downloaded the datasheets, so eventually for the 10.7 MHz filter the value of about 300 ohm for input and output impedance was sure.
I was kind of asking for confirmation about the role of the input resistive network. What it is still not clear to me is why the designer considered matching the input impedance as necessary, and, instead, he tolerated a direct connection of the output to an unmatched load (the NanoVNA). Maybe for the output he gave up since other resistors would make the signal too weak and he didn't mean to use capacitors or inductances for some reason?

A.

On Thu, Oct 29, 2020 at 02:09 AM, John Gord wrote:
Andrea,
I am not familiar with the band reject filter in circuit 5, but the filter in
circuit 6 is probably a fairly standard 10.7 MHz ceramic bandpass filter once
common in FM receivers. These filters are usually designed to work best with
a source impedance of 330 ohms and a load impedance of 330 ohms. Circuit 6
provides a load of 50 ohms to the source generator and a source impedance of
about 325 ohms to the filter (at the expense of loss in the resistors). The
load impedance presented to the filter is just the 50 ohms of the VNA port
(since they didn't use R7 and R11). The matching for the filter would have
been better with R7 and R11 at 300 ohms and 51 ohms, but I assume that they
were not used because the circuit as built is "good enough", and skipping the
resistive matching components gives a larger (if less properly filtered)
signal at the output.
--John Gord

On Wed, Oct 28, 2020 at 04:48 PM, Andrea IK0RNT wrote:


On Thu, Oct 29, 2020 at 12:40 AM, Andrea IK0RNT wrote:
Reading that to achieve the goal of maximum power transfer from a source
to
a
load just resistors could be used was definitely illuminating. Of course,
power waste in resistors would be an outstanding undesirable aspect. But
considering this chance I may finally understand what the designer of the
circuits 5 and 6 in the scrap I attach again - I still wonder what L1 is
for
in circuit 5, but I can wait to figure out this.
I'm sorry, I forgot to attach... :-(

A.
Re: nanoVNC -h

 

On Thu, Oct 29, 2020 at 08:03 AM, Roy J. Tellason, Sr. wrote:

I've run nothing but linux here since 1999. :-)
Since 2002 for me. Microsoft sucks.
Re: GetsScreenSE #applications

 

Nice small tool. Thank you! However, screenshots saved from my NanoVNA H (2.8" version) exhibit a dark blue shadow, for example next to the letters on the left hand side showing the calibration status. See attached file. This does not appear on screenshots taken with NanoVNA-Saver; so it's not a firmware issue.

Regards
Christian

29102020221959.png
nanovna-saver-for-comparison.png

Re: NanoVNA RF Demo Kit connection

 

hi Richard, I know what you mean - they are a 'very' tight fit, but soon loosen up .
As some have suggested they only have a limited number of fittings.
Re: NanoVNA RF Demo Kit connection

 

Use this link.

/g/nanovna-users/wiki/16592
Re: GetsScreenSE #applications

 

Here's the link for those interested in having a look:
/g/nanovna-users/files/NanoVNA%20PC%20Software/Screendump

On Thursday, October 29, 2020, 2:51:41 p.m. EDT, Karl Jan Skontorp <karl.jan.skontorp@...> wrote:

Hi folks!
I have made a Second Edition of my GetScreen program and uploaded it to the files section. The program now supports different models of the NanoVNA and also the nice tinySA. You can add lines, circle and text to the screen dumped to the PC and save it as png-file!
I hope you find it useful!

73s
Karl Jan - LA3FY
File /NanoVNA PC Software/Screendump/GetScreenSE.exe uploaded #file-notice

[email protected] Notification
 

The following files have been uploaded to the Files area of the [email protected] group.

By: Karl Jan Skontorp

Description:
The Second Edition of GetScreen program to a PC. The program now supports different models of the NanoVNA and also the nice tinySA.
GetsScreenSE #applications

 

Hi folks!
I have made a Second Edition of my GetScreen program and uploaded it to the files section. The program now supports different models of the NanoVNA and also the nice tinySA. You can add lines, circle and text to the screen dumped to the PC and save it as png-file!
I hope you find it useful!

73s
Karl Jan - LA3FY
SCPI equivalents?

 

I wonder if there's a semi-standard set of SCPI commands for commercial VNAs. Then one could make a SCPI : NanoVNA translation layer.

Why?
It might be useful to leverage other systems that have created abstractions for network analyzers in general.
21521 - 21540 of 39684