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Re: Improving the performance of a pre-V3.4 original Hugen nanoVNA

 

I'm very sorry, a typo, the TX (CH0) is not that bad, I measured and found while symulating 58.82 Ohms, *NOT 68.82 Ohms.
*

*Jos
*

Op 20-1-2020 om 15:49 schreef hugen@...:

On Mon, Jan 20, 2020 at 09:24 PM, hwalker wrote:

A similar discussion in Japanese (use Google translate or similar)
. His follow-up
discussions in January of this year are also an interesting read.

- Herb
I checked the content of this blog and some of the issues mentioned come from the wrong shield of the bad clone. Some modifications may not apply to a good NanoVNA. Our manufactured NanoVNA-H has good isolation.If you have better suggestions for improvements that can be feedback on github, we will try it and apply it to the next version of NanoVNA-H after verification, and send you the improved version to verify the modified effect.

hugen
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

Bob Albert
 

Mike,
Thanks for the information.? I did not buy the device because I have a second nano that does okay.? But after reading your latest suggestion I guess I'll buy the thing and see if I can upgrade without bricking the unit.? It should also be a door to future upgrades.? Perhaps I can upgrade the second nano via its USB port but that unit is flaky and turns itself off without provocation.? It won't even turn on while the port is connected, and sometimes even when not connected it fails.? Once on, I can connect the port.? Then suddenly it behaves properly.
I did have thoughts of replacing the USB connector but it takes ability that I lack.? I think over a dozen tightly spaced pins and limited access and tools.
Bob

On Monday, January 20, 2020, 10:38:13 AM PST, Bob Albert <bob91343@...> wrote:

Mike,
Thanks for the information.? I did not buy the device because I have a second nano that does okay.? But after reading your latest suggestion I guess I'll buy the thing and see if I can upgrade without bricking the unit.? It should also be a door to future upgrades.? Perhaps I can upgrade the second nano via its USB port but that unit is flaky and turns itself off without provocation.? It won't even turn on while the port is connected, and sometimes even when not connected it fails.? Once on, I can connect the port.? Then suddenly it behaves properly.
I did have thoughts of replacing the USB connector but it takes ability that I lack.? I think over a dozen tightly spaced pins and limited access and tools.
Bob

On Monday, January 20, 2020, 10:31:32 AM PST, Bob Albert via Groups.Io <bob91343@...> wrote:

Mike,
Thanks for the information.? I did not buy the device because I have a second nano that does okay.? But after reading your latest suggestion I guess I'll buy the thing and see if I can upgrade without bricking the unit.? It should also be a door to future upgrades.? Perhaps I can upgrade the second nano via its USB port but that unit is flaky and turns itself off without provocation.? It won't even turn on while the port is connected, and sometimes even when not connected it fails.? Once on, I can connect the port.? Then suddenly it behaves properly.
I did have thoughts of replacing the USB connector but it takes ability that I lack.? I think over a dozen tightly spaced pins and limited access and tools.
Bob
? ? On Monday, January 20, 2020, 10:13:05 AM PST, n2msqrp <mstangelo@...> wrote:

Bryan,

Thanks. I thought it had to do with the mismatch between the coax and S11 port. I had a length of RG-6 handy and see the same effect with that 75 ohm cable and see the same effect. Since the loss of the Rg-6 is higher the step responses is decreasing at a faster rate.

I have a 75 to 50 ohm pad. If I have time I may connect the pad to the S11 port, run a calibration using a 75 ohm load and run the test again.

Mike N2MS



Mike,

You need to think about what you are seeing in the time domain.? What the software produces is the impulse response (the positive going blips) and the step response (the steps in your plot) of the network attached.? The steps are the result of multiple trips of a wave traveling through your cable.? The part you are asking about is the step response of your cable.? Consider the following.
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

Bob Albert
 

Mike,
Thanks for the information.? I did not buy the device because I have a second nano that does okay.? But after reading your latest suggestion I guess I'll buy the thing and see if I can upgrade without bricking the unit.? It should also be a door to future upgrades.? Perhaps I can upgrade the second nano via its USB port but that unit is flaky and turns itself off without provocation.? It won't even turn on while the port is connected, and sometimes even when not connected it fails.? Once on, I can connect the port.? Then suddenly it behaves properly.
I did have thoughts of replacing the USB connector but it takes ability that I lack.? I think over a dozen tightly spaced pins and limited access and tools.
Bob

On Monday, January 20, 2020, 10:31:32 AM PST, Bob Albert via Groups.Io <bob91343@...> wrote:

Mike,
Thanks for the information.? I did not buy the device because I have a second nano that does okay.? But after reading your latest suggestion I guess I'll buy the thing and see if I can upgrade without bricking the unit.? It should also be a door to future upgrades.? Perhaps I can upgrade the second nano via its USB port but that unit is flaky and turns itself off without provocation.? It won't even turn on while the port is connected, and sometimes even when not connected it fails.? Once on, I can connect the port.? Then suddenly it behaves properly.
I did have thoughts of replacing the USB connector but it takes ability that I lack.? I think over a dozen tightly spaced pins and limited access and tools.
Bob
? ? On Monday, January 20, 2020, 10:13:05 AM PST, n2msqrp <mstangelo@...> wrote:

Bryan,

Thanks. I thought it had to do with the mismatch between the coax and S11 port. I had a length of RG-6 handy and see the same effect with that 75 ohm cable and see the same effect. Since the loss of the Rg-6 is higher the step responses is decreasing at a faster rate.

I have a 75 to 50 ohm pad. If I have time I may connect the pad to the S11 port, run a calibration using a 75 ohm load and run the test again.

Mike N2MS



Mike,

You need to think about what you are seeing in the time domain.? What the software produces is the impulse response (the positive going blips) and the step response (the steps in your plot) of the network attached.? The steps are the result of multiple trips of a wave traveling through your cable.? The part you are asking about is the step response of your cable.? Consider the following.
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

Bob Albert
 

Mike,
Thanks for the information.? I did not buy the device because I have a second nano that does okay.? But after reading your latest suggestion I guess I'll buy the thing and see if I can upgrade without bricking the unit.? It should also be a door to future upgrades.? Perhaps I can upgrade the second nano via its USB port but that unit is flaky and turns itself off without provocation.? It won't even turn on while the port is connected, and sometimes even when not connected it fails.? Once on, I can connect the port.? Then suddenly it behaves properly.
I did have thoughts of replacing the USB connector but it takes ability that I lack.? I think over a dozen tightly spaced pins and limited access and tools.
Bob

On Monday, January 20, 2020, 10:13:05 AM PST, n2msqrp <mstangelo@...> wrote:

Bryan,

Thanks. I thought it had to do with the mismatch between the coax and S11 port. I had a length of RG-6 handy and see the same effect with that 75 ohm cable and see the same effect. Since the loss of the Rg-6 is higher the step responses is decreasing at a faster rate.

I have a 75 to 50 ohm pad. If I have time I may connect the pad to the S11 port, run a calibration using a 75 ohm load and run the test again.

Mike N2MS



Mike,

You need to think about what you are seeing in the time domain.? What the software produces is the impulse response (the positive going blips) and the step response (the steps in your plot) of the network attached.? The steps are the result of multiple trips of a wave traveling through your cable.? The part you are asking about is the step response of your cable.? Consider the following.
Re: We started selling nanoVNA-H4 using STM3

 

Ok. Thanks.
On Mon, Jan 20, 2020 at 1:12 PM, Larry Rothman<nlroth@...> wrote: There is a link in the Wiki.

On Monday, January 20, 2020, 1:11:19 p.m. GMT-5, Chris ODonnell via Groups.Io <redrider17747@...> wrote:

Can you post the instruction sheet(s) shown behind the unit in the photo?
? On Sun, Jan 19, 2020 at 10:45 PM, RFy<gpdxdveil@...> wrote:? How fast full sweep and how many sweep points on this variants?
Re: Improving the performance of a pre-V3.4 original Hugen nanoVNA

 

Did you include the SA612 with power?
Using another vna I measured fairly accurate ch0 resistance with power on

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK
Re: Corrupted firmware.

 

Image attached.

USBDeview1.png

Re: Improving the performance of a pre-V3.4 original Hugen nanoVNA

 

90%+ Isopropyl Alcohol on a cotton swab will make quick work of that flux.

- Bill

On 2020-01-20 11:41, Reinier Gerritsen wrote:

Hi Eric,
Thanks for your experiments to improve the nanoVNA.
And buy some flux remover to clean up the mess
Reinier
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

 

Bryan,

Thanks. I thought it had to do with the mismatch between the coax and S11 port. I had a length of RG-6 handy and see the same effect with that 75 ohm cable and see the same effect. Since the loss of the Rg-6 is higher the step responses is decreasing at a faster rate.

I have a 75 to 50 ohm pad. If I have time I may connect the pad to the S11 port, run a calibration using a 75 ohm load and run the test again.

Mike N2MS


Mike,

You need to think about what you are seeing in the time domain. What the software produces is the impulse response (the positive going blips) and the step response (the steps in your plot) of the network attached. The steps are the result of multiple trips of a wave traveling through your cable. The part you are asking about is the step response of your cable. Consider the following.
Re: Corrupted firmware.

 

Ok, so one last try with USBDeview. In the image you can see where I've highlighted a Port_#002.Hub, SMT32 Bootloader line. However, the very last line is what shows up when I reset and enable DFU on my nanoVNA. The serial number looks corrupted, does this mean that I must recover using the ST-Link v2 dongle? I think I saw where that is less than $2 USD on the Chinese website.

73, Brian
Re: We started selling nanoVNA-H4 using STM3

 

There is a link in the Wiki.

On Monday, January 20, 2020, 1:11:19 p.m. GMT-5, Chris ODonnell via Groups.Io <redrider17747@...> wrote:

Can you post the instruction sheet(s) shown behind the unit in the photo?
? On Sun, Jan 19, 2020 at 10:45 PM, RFy<gpdxdveil@...> wrote:? How fast full sweep and how many sweep points on this variants?
Re: We started selling nanoVNA-H4 using STM3

 

Can you post the instruction sheet(s) shown behind the unit in the photo?
On Sun, Jan 19, 2020 at 10:45 PM, RFy<gpdxdveil@...> wrote: How fast full sweep and how many sweep points on this variants?
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

 

Bob,
Flash the latest firmware.
TDR functionality has been part of most Nano firmware since mid Oct.
I know your USB connector is pooched but did you ever buy the STM-Link device I gave you the link for?
I've used it to test-flash my device in case the USB every screwed-up - and it works fine.
...Larry

On Monday, January 20, 2020, 12:55:07 p.m. GMT-5, Bob Albert via Groups.Io <bob91343@...> wrote:

How can I add TDR capability to my early version of the nano?
? ? On Monday, January 20, 2020, 09:53:16 AM PST, n2msqrp <mstangelo@...> wrote:

I've added a screenshot of the display to the Pictures Section

Mike N2MS

On January 20, 2020 at 11:08 AM n2msqrp <mstangelo@...> wrote:


I've been checking my coax using NanaVNA Saver 0.2.2-1 on a NanoVNA-H with Hugen 0.4.5-4-g96e7efe firmware.

I have a piece of 75 ohm Commscope F-11 coax going to a junction box in the yard, I believe thet the far end is open.

I ran the TDR? function. The Estimated cable length 41.104m (134ft 10.3in) seems correct but I don't understand why I get this stair step graph with reflections at multiples of the 41.1m length.
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

Bob Albert
 

How can I add TDR capability to my early version of the nano?

On Monday, January 20, 2020, 09:53:16 AM PST, n2msqrp <mstangelo@...> wrote:

I've added a screenshot of the display to the Pictures Section

Mike N2MS

On January 20, 2020 at 11:08 AM n2msqrp <mstangelo@...> wrote:


I've been checking my coax using NanaVNA Saver 0.2.2-1 on a NanoVNA-H with Hugen 0.4.5-4-g96e7efe firmware.

I have a piece of 75 ohm Commscope F-11 coax going to a junction box in the yard, I believe thet the far end is open.

I ran the TDR? function. The Estimated cable length 41.104m (134ft 10.3in) seems correct but I don't understand why I get this stair step graph with reflections at multiples of the 41.1m length.
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

 

I've added a screenshot of the display to the Pictures Section

Mike N2MS

On January 20, 2020 at 11:08 AM n2msqrp <mstangelo@...> wrote:


I've been checking my coax using NanaVNA Saver 0.2.2-1 on a NanoVNA-H with Hugen 0.4.5-4-g96e7efe firmware.

I have a piece of 75 ohm Commscope F-11 coax going to a junction box in the yard, I believe thet the far end is open.

I ran the TDR function. The Estimated cable length 41.104m (134ft 10.3in) seems correct but I don't understand why I get this stair step graph with reflections at multiples of the 41.1m length.
Re: TDR Measurement with NanoVNA Saver #nanovna-saver #tdr

 

On Mon, Jan 20, 2020 at 09:08 AM, n2msqrp wrote:


I ran the TDR function. The Estimated cable length 41.104m (134ft 10.3in)
seems correct but I don't understand why I get this stair step graph with
reflections at multiples of the 41.1m length.
Mike,

You need to think about what you are seeing in the time domain. What the software produces is the impulse response (the positive going blips) and the step response (the steps in your plot) of the network attached. The steps are the result of multiple trips of a wave traveling through your cable. The part you are asking about is the step response of your cable. Consider the following.

The incident wave traveling through your cable reaches the end of the cable and is reflected by the open circuit back down the cable toward the VNA. This initial reflection represents the time-domain measurement of your cable's length and is the first step and impulse in the TDR plots. A factor of 2 and cable velocity factor is included in the software to convert from the true time domain value to equivalent cable length. Because the cable and the VNA are not matched, there is a reflection when the traveling wave reaches the vna. As a result, another wave is launched back along the cable toward the open end. This is repeated until the signal is completely absorbed by losses in the cable and the load in your vna or your run out of time-domain analysis capability with the software approach used. In this case you can't plot a later time due to limitations of the sampling done by the VNA. Notice that in the impulse response the impulses are getting smaller and smaller as time increases. This is due to the loss in the cable and the impedance match between the cable and the VNA's input impedance. Unless you want to consider all of the details of the transmission line setup you have created which includes complex values of losses, impedance, open circuit, reflection coefficient of the VNA input, etc, it is easiest to ignore all of the information after the time-domain value represented by the length of the cable. However, if you go through the full details of the step response of the network you have created (including the cable, the specific open circuit at the end of the cable, and the input of the VNA), you should be able to reproduce what nanoVNA-Saver is observing. For checking cables, this is usually not very useful, but it is possible.

I hope this helps explain what you are seeing.

--
Bryan, WA5VAH
Re: *** FIX FOR NANOVNA-SAVER PYQT5 INSTALLATION PROBLEMS ON LINUX MINT 19.3 *** #nanovna-saver

 

/g/nanovna-users/files/NanoVNA%20PC%20Software/NanoVNA-Saver/nvna-s-pve-rev-b.pdf

- typos fixed.
Re: New user: NanoVNA-H how to determine hardware version

 

On Mon, Jan 20, 2020 at 08:29 AM, Alan G3XAQ wrote:

" None of this seems to tell me which hardware version I have received. I've trawled the messages on here and can't see how to find it. "
==============================================================
Alan,
I have both NanoVNA-H versions 3.3 and 3.4. I found the easiest way to tell the difference between versions, without opening the case, is turning the unit off and observing the power LED. On ver 3.4 the LED extinguishes immediately, whilst on ver 3.3 it stays illuminated for a few moments like the original NanoVNA.

- Herb
Re: Improving the performance of a pre-V3.4 original Hugen nanoVNA

 

Well, I did the component changes on my version 3.3 to version 3.4 NanoVNA-H (resistors only).

Using my 4 point precission LCR measuring device I measured @ 10kHz? directly on the connectors, VNA power off :

CH0 = 68.82 Ohms (not so good)

CH1 = 50.268 Ohms (good)

I did a low frequency symulation of the in- and output-circuits and the results are conform my measurements.

For what it's worth, certainly not for HF and high up.

Jos

I

Op 20-1-2020 om 15:49 schreef hugen@...:

On Mon, Jan 20, 2020 at 09:24 PM, hwalker wrote:

A similar discussion in Japanese (use Google translate or similar)
. His follow-up
discussions in January of this year are also an interesting read.

- Herb
I checked the content of this blog and some of the issues mentioned come from the wrong shield of the bad clone. Some modifications may not apply to a good NanoVNA. Our manufactured NanoVNA-H has good isolation.If you have better suggestions for improvements that can be feedback on github, we will try it and apply it to the next version of NanoVNA-H after verification, and send you the improved version to verify the modified effect.

hugen
Re: We started selling nanoVNA-H4 using STM32F303CCT6 and 4-inch LCD

Ivan Alie
 

I just had contact with Maggie less then 3 hours ago, and made payment via paypal.
Also she sayd its CNY overthere so will be at work again for shipping the goods February 4
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