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Date
Re: NanoVNA -H #nanovna-h

 

Hi Rob,

DiSlord supports the NanoVNA-H (and other devices) actively:


Martin
Re: New member with a NanoVna H4

 

On 10/4/22 11:00 AM, Lester Veenstra via groups.io wrote:
Yes keeping in mind the termination need to be a short or open.
Then as a function of length and frequency any +/- imaginary value (C or L) can be presented at the other end.
Not *any* - for a given length, you get a circle/spiral on the Smith chart of values


Impedance transformations
If a load of complex impedance Zload is connected to the end of a transmission line of characteristic impedance Z0 (which may be complex), the impedance at the other end of the line is Zin, calculated by the following equation:

Zin = Z0 * (Zload*cosh(gamma) + Z0*sinh(gamma))/ (Zload*sinh(gamma)+Z0*cosh(gamma))
gamma is the complex propagation constant. gamma = alpha + j beta where:

alpha is attenuation in nepers (1 neper = 8.688 dB)
beta is length in radians

Some cases of interest are where alpha=0 (i.e. a lossless line) in which case the hyperbolic functions turn into their trig equivalents, and where beta is pi/2 or pi.

If beta = pi/2 (a half wavelength line), then cosh(gamma) = -1 and sinh(gamma) = 0, so you get:

Zin = Zload
If beta = pi/4 ( a quarter wavelength line), then cosh(gamma) = 0 and sinh(gamma) = 1, so you get:

Zin = Z0 * Z0/Zload
or, written another way:

Zin * Zload = Z0*Z0
This is the basis of the popular 1/4 wave impedance transformers... To transform Zin to Zload, you need only construct a quarter wave line with impedance = sqrt(Zin*Zload)
NanoVNA -H #nanovna-h

Rob Greaves
 

Can anyone tell me the latest version of firmware and link please. Totally confused so far. Thanks
Re: New member with a NanoVna H4

 

Yes keeping in mind the termination need to be a short or open.
Then as a function of length and frequency any +/- imaginary value (C or L) can be presented at the other end.

Lester B Veenstra K1YCM M?YCM W8YCM 6Y6Y
lester@...

452 Stable Ln (HC84 RFD USPS Mail)
Keyser WV 26726

GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)


Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Bryan Curl
Sent: Tuesday, October 04, 2022 1:52 PM
To: [email protected]
Subject: Re: [nanovna-users] New member with a NanoVna H4

Lester,
Sorry to scope creep on the thread but this is interesting.

so you are saying that a parallel tuning stub could be open or shorted and depending on the length to termination, could be seen by the network as an inductance or capacitance?

Bryan.
Re: New member with a NanoVna H4

 

Lester,
Sorry to scope creep on the thread but this is interesting.

so you are saying that a parallel tuning stub could be open or shorted and depending on the length to termination, could be seen by the network as an inductance or capacitance?

Bryan.
Re: New member with a NanoVna H4

 

On 10/4/22 4:35 AM, Bryan Curl wrote:
Both articles well done. Thanks. I have had some good success matching antenna impedance using the smith chart but using a chunk of coax for a shunt inductor eludes me. Could that possibly be the shorted tuning stub as apposed to the open ended one?
Yes, you can make inductance or capacitance with a shorted or open stub, with some limitations.
Re: New member with a NanoVna H4

 

Both will work, of course, different lengths at a given frequency for the same inductance or capacitance at the user's end

Lester B Veenstra K1YCM M?YCM W8YCM 6Y6Y
lester@...

452 Stable Ln (HC84 RFD USPS Mail)
Keyser WV 26726

GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)


Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Bryan Curl
Sent: Tuesday, October 04, 2022 7:36 AM
To: [email protected]
Subject: Re: [nanovna-users] New member with a NanoVna H4

Both articles well done. Thanks. I have had some good success matching antenna impedance using the smith chart but using a chunk of coax for a shunt inductor eludes me. Could that possibly be the shorted tuning stub as apposed to the open ended one?
Anyway, Stan, thanks for the lead to great articles.

Regards,
Bryan
Re: New member with a NanoVna H4

 

Both articles well done. Thanks. I have had some good success matching antenna impedance using the smith chart but using a chunk of coax for a shunt inductor eludes me. Could that possibly be the shorted tuning stub as apposed to the open ended one?
Anyway, Stan, thanks for the lead to great articles.

Regards,
Bryan
Re: Replacement of damaged NanoVNA circuit board #hardware

 

I can envision the potential for lots of coupling due to either magnetic field or capacitive coupling at nasty power line harmonics which can extend out quite far in frequency.

On 10/2/2022 11:24 AM, linhz0hz@... wrote:
I am interested if anyone figured this out, because I just fried mine nanoVNA SAA-2N just now. -_-!

I was building some homebrew amplifier. Before measuring that, I wanted to calibrate the test PCB before I put in my transistor. So I would solder different resistors on the board and take measurement. The board is not powered (completely passive).
It was tedious, I got lazy and did not remove my nanoVNA while I solder. I had DC-blocking capacitors though and I got away doing that a few times before so I imagined it would be fine.

But apparently it is not fine this time. Now if I just connect Tx to Rx port, I got high reflection (close to an open) and only -20dB transmission. Software part seems to work still, so I suspect RF front end was killed. I open the casing and took a look, but I don't want to make a rush decision and break it further. Also those EMI shields looks hard to remove.

So does anyone have advice for me on what is the most efficient way to repair? And do you expect a soldering iron to have damage like this (I still don't fully believe it!) or is this something else?
Re: New member with a NanoVna H4

 

Many thanks to everyone for replies.

Im still playing about with the device, and very impressed. Just wish i could could Mr J Smiths software to work, although i believe hes stopped development and the version available seems to be for the vnalite.
Has anyone managed to get the Nanovna solver 64 to work on a nanovna H4?
Yes the other available software seems good, but i like the look of the features of Mr Smiths Solver.

regards Pete
Re: Firmware instalation problem #firmware

 

Are you certain that you are actually downloading to the NanoVNA, and not possibly uploading the old from it, and overwriting your image?
If you errantly did that even once, subsequent correct attempts might be successfully putting the old image back on . . .

On October 3, 2022 10:44:40 AM CDT, jlcalabro@... wrote:
Hello, I have a nanovna H4 I downloaded the firmware and installing it with the Dfuse program, all very well, but the firmware in the H4 not change, it remains the same, any suggestion? Thank you




--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
Firmware instalation problem #firmware

 

Hello, I have a nanovna H4 I downloaded the firmware and installing it with the Dfuse program, all very well, but the firmware in the H4 not change, it remains the same, any suggestion? Thank you
Re: Replacement of damaged NanoVNA circuit board #hardware

 

The WTCP irons are not cheap irons. I have three of them at work. I can
verify that the tips are grounded.

I have a cheapie Weller 25 watt iron that I added a solder lug and a wire
with an alligator clip on to one of the three screws that hold the metal
heating assembly onto the plastic case. I use that th ground the tip.

Zack W9SZ

On Sun, Oct 2, 2022 at 11:01 PM KENT BRITAIN <WA5VJB@...> wrote:

Yes, and I have seem the ground pin cut off, and I have seen miss wired
wall sockets.
Just letting people know that simple/cheap soldering Irons can kill
digital electronics. Kent

On Sunday, October 2, 2022 at 08:38:29 PM CDT, Jim Lux <
jimlux@...> wrote:

On 10/2/22 5:37 PM, KENT BRITAIN wrote:
If you measure capacitance between the AC cord to the Iron tip, you get
about 200 pf.
The AC voltage is capacitively coupled to the Iron tip unless you have a
specially grounded IRON,(And have the Ground Connected)
So the average soldering iron is a 200 pf cap plugged into 120 VAC going
to your circuit. Kent

The typical Weller WTCP irons all have grounded tips.



On Sunday, October 2, 2022 at 05:33:28 PM CDT, <
linhz0hz@...> wrote:

I am interested if anyone figured this out, because I just fried mine
nanoVNA SAA-2N just now. -_-!

I was building some homebrew amplifier. Before measuring that, I wanted
to calibrate the test PCB before I put in my transistor. So I would solder
different resistors on the board and take measurement. The board is not
powered (completely passive).
It was tedious, I got lazy and did not remove my nanoVNA while I solder.
I had DC-blocking capacitors though and I got away doing that a few times
before so I imagined it would be fine.

But apparently it is not fine this time. Now if I just connect Tx to Rx
port, I got high reflection (close to an open) and only -20dB transmission.
Software part seems to work still, so I suspect RF front end was killed. I
open the casing and took a look, but I don't want to make a rush decision
and break it further. Also those EMI shields looks hard to remove.

So does anyone have advice for me on what is the most efficient way to
repair? And do you expect a soldering iron to have damage like this (I
still don't fully believe it!) or is this something else?
Re: NanoVNA-h4 stuck in DFU mode

 

Eric,
You need the Device manager to show that you have a DFU device installed.
Using the Device Manager (DM), and with the nano connected, delete any STM bootloader device(s) shown.
Then, use Zadig to install the correct driver. (check the forum Wiki)
Once you see a DFU driver, you can flash the device.

As for your device stuck in DFU mode, turn it off & remove battery.
Check continuity from Boot0 pin to both Gnd and Vdd pin (NOT Vcc!)
-DO NOT- use an ohmmeter that has over 1V at the probes!
Without the Jog SW pressed, and with no jumper from Boot0 to Vdd, there should be no connection to Gnd or Vdd.
Some jog switches get stuck when pressed-inward causing a permanent DFU.

Good luck!

...Larry
Re: Advice on which FW to load SAA-2N v2_2

 

Let me know how you go, I am also interested to do that.
Re: Replacement of damaged NanoVNA circuit board #hardware

 

This thread may be helpful: /g/nanovna-users/topic/80361897#20422
Reinier

On October 3, 2022 8:06 AM Reinier Gerritsen <r.gerritsen@...> wrote:


Working on 900 MHz patch antennas (copper foil for tuning and matching) with about 1 or 2 meter of coax to the (original) SAA-V2, I had 3 broken units (1 from my customer). All revived by replacing the switch ic directly at the input. Search in the nanoVNAV2 group for details on repair and how to add protection.

Success, Reinier

On October 2, 2022 5:24 PM linhz0hz@... wrote:


I am interested if anyone figured this out, because I just fried mine nanoVNA SAA-2N just now. -_-!

I was building some homebrew amplifier. Before measuring that, I wanted to calibrate the test PCB before I put in my transistor. So I would solder different resistors on the board and take measurement. The board is not powered (completely passive).
It was tedious, I got lazy and did not remove my nanoVNA while I solder. I had DC-blocking capacitors though and I got away doing that a few times before so I imagined it would be fine.

But apparently it is not fine this time. Now if I just connect Tx to Rx port, I got high reflection (close to an open) and only -20dB transmission. Software part seems to work still, so I suspect RF front end was killed. I open the casing and took a look, but I don't want to make a rush decision and break it further. Also those EMI shields looks hard to remove.

So does anyone have advice for me on what is the most efficient way to repair? And do you expect a soldering iron to have damage like this (I still don't fully believe it!) or is this something else?



Re: Replacement of damaged NanoVNA circuit board #hardware

 

Working on 900 MHz patch antennas (copper foil for tuning and matching) with about 1 or 2 meter of coax to the (original) SAA-V2, I had 3 broken units (1 from my customer). All revived by replacing the switch ic directly at the input. Search in the nanoVNAV2 group for details on repair and how to add protection.

Success, Reinier

On October 2, 2022 5:24 PM linhz0hz@... wrote:


I am interested if anyone figured this out, because I just fried mine nanoVNA SAA-2N just now. -_-!

I was building some homebrew amplifier. Before measuring that, I wanted to calibrate the test PCB before I put in my transistor. So I would solder different resistors on the board and take measurement. The board is not powered (completely passive).
It was tedious, I got lazy and did not remove my nanoVNA while I solder. I had DC-blocking capacitors though and I got away doing that a few times before so I imagined it would be fine.

But apparently it is not fine this time. Now if I just connect Tx to Rx port, I got high reflection (close to an open) and only -20dB transmission. Software part seems to work still, so I suspect RF front end was killed. I open the casing and took a look, but I don't want to make a rush decision and break it further. Also those EMI shields looks hard to remove.

So does anyone have advice for me on what is the most efficient way to repair? And do you expect a soldering iron to have damage like this (I still don't fully believe it!) or is this something else?


Re: Replacement of damaged NanoVNA circuit board #hardware

 

Yes, and I have seem the ground pin cut off, and I have seen miss wired wall sockets.
Just letting people know that simple/cheap soldering Irons can kill digital electronics.? Kent

On Sunday, October 2, 2022 at 08:38:29 PM CDT, Jim Lux <jimlux@...> wrote:

On 10/2/22 5:37 PM, KENT BRITAIN wrote:
? If you measure capacitance between the AC cord to the Iron tip, you get about 200 pf.
The AC voltage is capacitively coupled to the Iron tip unless you have a specially grounded IRON,(And have the Ground Connected)
So the average soldering iron is a 200 pf cap plugged into 120 VAC going to your circuit.? Kent
The typical Weller WTCP irons all have grounded tips.



? ? ? On Sunday, October 2, 2022 at 05:33:28 PM CDT, <linhz0hz@...> wrote:
?
? I am interested if anyone figured this out, because I just fried mine nanoVNA SAA-2N just now. -_-!

I was building some homebrew amplifier. Before measuring that, I wanted to calibrate the test PCB before I put in my transistor. So I would solder different resistors on the board and take measurement. The board is not powered (completely passive).
It was tedious, I got lazy and did not remove my nanoVNA while I solder. I had DC-blocking capacitors though and I got away doing that a few times before so I imagined it would be fine.

But apparently it is not fine this time. Now if I just connect Tx to Rx port, I got high reflection (close to an open) and only -20dB transmission. Software part seems to work still, so I suspect RF front end was killed. I open the casing and took a look, but I don't want to make a rush decision and break it further. Also those EMI shields looks hard to remove.

So does anyone have advice for me on what is the most efficient way to repair? And do you expect a soldering iron to have damage like this (I still don't fully believe it!) or is this something else?





? ?




Re: Replacement of damaged NanoVNA circuit board #hardware

 

I would also think that even if a tip did have capacitive coupling, unless the board had earth ground somewhere, that no current would flow . . . .kinda like a bird on a power lime.

On October 2, 2022 8:38:18 PM CDT, Jim Lux <jimlux@...> wrote:
On 10/2/22 5:37 PM, KENT BRITAIN wrote:
If you measure capacitance between the AC cord to the Iron tip, you get about 200 pf.
The AC voltage is capacitively coupled to the Iron tip unless you have a specially grounded IRON,(And have the Ground Connected)
So the average soldering iron is a 200 pf cap plugged into 120 VAC going to your circuit.? Kent
The typical Weller WTCP irons all have grounded tips.



On Sunday, October 2, 2022 at 05:33:28 PM CDT, <linhz0hz@...> wrote:
I am interested if anyone figured this out, because I just fried mine nanoVNA SAA-2N just now. -_-!

I was building some homebrew amplifier. Before measuring that, I wanted to calibrate the test PCB before I put in my transistor. So I would solder different resistors on the board and take measurement. The board is not powered (completely passive).
It was tedious, I got lazy and did not remove my nanoVNA while I solder. I had DC-blocking capacitors though and I got away doing that a few times before so I imagined it would be fine.

But apparently it is not fine this time. Now if I just connect Tx to Rx port, I got high reflection (close to an open) and only -20dB transmission. Software part seems to work still, so I suspect RF front end was killed. I open the casing and took a look, but I don't want to make a rush decision and break it further. Also those EMI shields looks hard to remove.

So does anyone have advice for me on what is the most efficient way to repair? And do you expect a soldering iron to have damage like this (I still don't fully believe it!) or is this something else?












--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
Re: Replacement of damaged NanoVNA circuit board #hardware

 

On 10/2/22 5:37 PM, KENT BRITAIN wrote:
If you measure capacitance between the AC cord to the Iron tip, you get about 200 pf.
The AC voltage is capacitively coupled to the Iron tip unless you have a specially grounded IRON,(And have the Ground Connected)
So the average soldering iron is a 200 pf cap plugged into 120 VAC going to your circuit.? Kent
The typical Weller WTCP irons all have grounded tips.

On Sunday, October 2, 2022 at 05:33:28 PM CDT, <linhz0hz@...> wrote:
I am interested if anyone figured this out, because I just fried mine nanoVNA SAA-2N just now. -_-!
I was building some homebrew amplifier. Before measuring that, I wanted to calibrate the test PCB before I put in my transistor. So I would solder different resistors on the board and take measurement. The board is not powered (completely passive).
It was tedious, I got lazy and did not remove my nanoVNA while I solder. I had DC-blocking capacitors though and I got away doing that a few times before so I imagined it would be fine.
But apparently it is not fine this time. Now if I just connect Tx to Rx port, I got high reflection (close to an open) and only -20dB transmission. Software part seems to work still, so I suspect RF front end was killed. I open the casing and took a look, but I don't want to make a rush decision and break it further. Also those EMI shields looks hard to remove.
So does anyone have advice for me on what is the most efficient way to repair? And do you expect a soldering iron to have damage like this (I still don't fully believe it!) or is this something else?
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