Re: Question on remote use of NanoVNA
Stan Dye,
Thank you so much for that feed back. It helps. I have a few older cell's here to play with.
Andy
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Re: where is the end fed natural resonance
On Sun, Mar 3, 2024 at 11:04 AM, W0LEV wrote:
But given the small difference between the S21 and the Y21 method, I'll
continue with the S21 method.
It's not always small, Dave. The first plot shows VNA R & X for data from a ground probe using a two-port series measurement. The second plot shows the resulting ground permittivity and conductivity. Dim traces are for the S21 method, normal traces are for Y21. The Y21 permittivity and conductivity traces are similar to those derived from a single-port S11 measurement. The traces for the S21 method are in left field. In this application, common-mode current arises because the unknown (ground) is distributed and easily couples to the VNA cables and the VNA itself. It manifests itself as rather large stray shunt impedances. The Y21 method effectively null them. Brian
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Re: Question on remote use of NanoVNA
Andrew, I had some success with the app and method you referred to in your last post.
Consider the following general setup:
a) the nanoVNA is connected to an android cell phone using a usb cable
b) the cell phone is used as a WIFI connection to the nanoVNA
c) I access the nanoVNA via WIFI from my computer using the nanovna-app software.
I successfully performed the following:
1) on an old cell phone (samsung s6 edge, which doesn't even have a sim card installed):
1a) I connected the phone to my home WIFI, and noted the IP address it used for the connection
1b) I downloaded the TCPUART app by "hardcoded" from the app store (a free app)
1c) I connected the phone to my nanoVNA-H4 using an old USB-OTG cable and a USB-A to USB-C cable
1d) I ran the TCPUART app and turned on the nano, then clicked the 'connect' button in the top USB_UART section of the app.
1e) the phone popped up a prompt asking if I wanted to allow the connection, I pressed OK, and it showed I was connected to the nanovna.
2) I started the nanovna-app software on my computer and connected it to the nanovna.
2a) on the TCPUART app on the phone, In the TCP connection part, I clicked on "server" and left it set for port 8080
2b) in the nanovna-app, at the top to the right of the connect button, I entered the phone's WIFI IP address I had previously noted, and port 8080
2c) above the connect button, I selected the TCP/IP connection port from the drop down
2d) I connected, and everything is working.
Now as long as I keep the phone with the nano, I can remotely use it anywhere via my home wifi and the nanovna-app. I can use a rubber band to hold the nano and the phone together as a unit and readily use it remotely.
So the old post from pcg1682 will still work just fine.
I have not yet checked if the OTG cable is really required - the app vendor suggests it may be. I needed to use it to convert from the phone's micro-usb to the usb-c on the nano.
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Re: where is the end fed natural resonance
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Re: where is the end fed natural resonance
Absolutely excellent paper:
But given the small difference between the S21 and the Y21 method, I'll
continue with the S21 method.
Dave - W?LEV
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On Sun, Mar 3, 2024 at 12:45?AM Brian Beezley <k6sti@...> wrote: On Sat, Mar 2, 2024 at 03:13 PM, Stan Dye wrote:
If you read along in his description, he shows his calculated resonant
frequencies of the choke for different versions of the antenna in a
table.
He notes that it should be resonant a bit below the band for a wider-band
antenna response, and close to the lower band edge for a narrow band
antenna.
The way I'd design this antenna is to resonate the choke at the frequency
of interest. That will minimize unwanted current on the feedline below. I'd
calculate the necessary coil length and number of turns. Using a test coil,
I'd adjust one or the other for resonance with a NanoVNA and the Y21 method:
Note that PVC and ABS are not the best coil form materials. PEX is less
lossy. Styrofoam has negligible loss, but it may not be strong enough
mechanically and might also capture moisture.
Then I'd duplicate the test coil in the actual antenna and adjust the
dipole dimensions for minimum SWR at the target frequency. Unless I needed
to minimize the size and weight of a portable antenna, I'd probably add a
second choke a quarter wavelength below the first to suppress any residual
current. If the feedline drops straight below the dipole for some distance,
all this should result in low common-mode current and a clean radiation
pattern.
Brian
-- *Dave - W?LEV*
--
Dave - W?LEV
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Re: Question on remote use of NanoVNA
I¡¯d start looking for a combination of apps/devices that can tunnel a USB connection, or, alternately, the serial port over USB.
The thing you hook up to the NanoVNA needs to be a USB-C host that can open the serial port. And it needs to send the serial data.
I would imagine a Raspberry Pi, Beagleboard, or maybe even some Arduinos can do this - I¡¯ve run NanoVNAs from a RPi, but I ran Python code on the Pi that interacted with the serial port. What you would need is some sort of ¡°network serial port¡± application - they exist, but I don¡¯t know any offhand.
And of course, you¡¯d need to rig up a battery to power the Pi, and set it up headless.
You might be able to do some sort of VNC or Remote Desktop to the Pi from your PC - that works quite well - I do it all the time from both Mac and PC. I don¡¯t know if you can tunnel the USB or Serial port with VNC, though.
Note that googling this is going to be a bit of work - you¡¯ll get lots of ¡°how to run VNC with a serial port¡± not ¡°how to remote a serial port with VNC¡±. The latter is what you want.
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On Mar 3, 2024, at 6:07?AM, Andrew Harman <Nexus9d9@...> wrote:
?On Sat, Mar 2, 2024 at 10:25 AM, Dragan Milivojevic wrote:
You were provided with a BT and WiFi solution but you persist for some reason. Dragan,
You obviously missed a few points. I'd personally like to hear more on it as the the application I'm looking for has not in fact been provided.
What has been said - your provided solution was for a H4. And as I have stated several times I have the H. There are differences in the board and as I understand as with the web app the difference may require a OTG adapter on one model and not the other. The interface therefore in your BT-Wifi solution could not be absolutely the same.
This is important, I have also stated that I was looking for a "canned" solution, meaning out of the package. I am disabled, took it in my third tour, so am not looking to dissect, modify or solder inside the Nanovna. Plug and play hardware with some software loading is what the goal is.
Andy
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Re: Question on remote use of NanoVNA
This seems to be using a android phone as one end of a serial port bridge: that is, it emulates the serial port over USB, just one would directly connected, and then on the other (PC) end, Trueport is the virtual serial port. Judging from the name of the android app, I¡¯m guessing it encapsulates the serial traffic in TCP/IP.
My own experience with Android phones and such is that 4 years is a very long time for an app or interface to continue working. This solution might depend on specific versions of Android (note that the author mentions that the phone was not new at the time).
V5.0-5.1 is Lollipop, 5.1 came out in 2015.
It is intriguing to not have to ¡°modify¡± your NanoVNA - just plug in the USB-C, but this particular approach is going to take a fair amount of tinkering, and finding a current set of apps (on phone and PC) that can do what¡¯s needed.
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On Mar 3, 2024, at 8:42?AM, Andrew Harman <Nexus9d9@...> wrote:
?From a 4 year old post, I'm looking more to this:
pgc1682@...
03/06/20 #11557
Hi,
Now, I have good succes Nanovna WIFI mode with Android phone (Samsung Xcover 3). Nanovna connected to phone with USB-OTG cable. This phone not new, Android 5.1.1. I use on phone TCPUART by hardcoded joy. On pc I use Trueport. Nanovna saver not detect automatically the Nanovna, but manual port settings works. Stable connection, vna works well. But Nanovna Saver device screenshot function always crash. I try with router works, I try without router and without mobile internet, Phone simply switch to hotspot mode. Works well too.
I not know how to contact Nanovna webapp developer. I think tcp serial data stream support easy upgrade.
73,
Lajos
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Re: Question on remote use of NanoVNA
From a 4 year old post, I'm looking more to this:
pgc1682@...
03/06/20 #11557
Hi,
Now, I have good succes Nanovna WIFI mode with Android phone (Samsung Xcover 3). Nanovna connected to phone with USB-OTG cable. This phone not new, Android 5.1.1. I use on phone TCPUART by hardcoded joy. On pc I use Trueport. Nanovna saver not detect automatically the Nanovna, but manual port settings works. Stable connection, vna works well. But Nanovna Saver device screenshot function always crash. I try with router works, I try without router and without mobile internet, Phone simply switch to hotspot mode. Works well too.
I not know how to contact Nanovna webapp developer. I think tcp serial data stream support easy upgrade.
73,
Lajos
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Re: Question on remote use of NanoVNA
I have H and H4 modified the same way. H4 is simpler as you only have to
solder a connector and make an opening in the case. OTG has nothing to do
with BT or with other solutions since the Nano is battery powered. If you
can't solder attach your Nano to any SBC like Raspberry Pi or similar and
export the serial port over IP.
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On Sun, 3 Mar 2024, 15:07 Andrew Harman, <Nexus9d9@...> wrote: On Sat, Mar 2, 2024 at 10:25 AM, Dragan Milivojevic wrote:
You were provided with a BT and WiFi solution but you persist for some reason.
Dragan,
You obviously missed a few points. I'd personally like to hear more on it
as the the application I'm looking for has not in fact been provided.
What has been said - your provided solution was for a H4. And as I have
stated several times I have the H. There are differences in the board and
as I understand as with the web app the difference may require a OTG
adapter on one model and not the other. The interface therefore in your
BT-Wifi solution could not be absolutely the same.
This is important, I have also stated that I was looking for a "canned"
solution, meaning out of the package. I am disabled, took it in my third
tour, so am not looking to dissect, modify or solder inside the Nanovna.
Plug and play hardware with some software loading is what the goal is.
Andy
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Re: Question on remote use of NanoVNA
On Sat, Mar 2, 2024 at 10:25 AM, Dragan Milivojevic wrote: You were provided with a BT and WiFi solution but you persist for some reason. Dragan, You obviously missed a few points. I'd personally like to hear more on it as the the application I'm looking for has not in fact been provided. What has been said - your provided solution was for a H4. And as I have stated several times I have the H. There are differences in the board and as I understand as with the web app the difference may require a OTG adapter on one model and not the other. The interface therefore in your BT-Wifi solution could not be absolutely the same. This is important, I have also stated that I was looking for a "canned" solution, meaning out of the package. I am disabled, took it in my third tour, so am not looking to dissect, modify or solder inside the Nanovna. Plug and play hardware with some software loading is what the goal is. Andy
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Re: where is the end fed natural resonance
On Sat, Mar 2, 2024 at 04:45 PM, Brian Beezley wrote:
Using a test coil, I'd adjust one or the other for resonance with a NanoVNA
and the Y21 method
Much simpler to just place the coil between the two ports and adjust for minimum |S21|. There will be a deep notch at self-resonance. I verified with a circuit simulation that the notch frequency doesn't vary with shunt port capacitance, which is what the Y21 method addresses. It also doesn't change with stray series inductance due to the leads. The self-resonant frequency will be sensitive to nearby objects and to stray capacitance across the coil. Best to hang it in air if possible. At least place it on a thick dielectric with low permittivity, such as styrofoam. Keep the coil far away from anything conductive or ferromagnetic. If anyone sees a problem with this method, please speak up. It seems too easy for something as sensitive as coil self-resonance. Brian
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Re: Which version of the firmware supports rotary encoders
Hi,
The DeepVNA-101 only supports Deep Elec firmware. The latest version is V1.0.5.
It does not support FW written for the NanoVNA-H /-H4 by Hugen or DiSlord.
HTH...Bob VK2ZRE
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On 3/03/2024 8:18 pm, blackberryer wrote: At present, this toggle switch, always feels not silky enough, not sensitive enough, look at the latest version of DEEPVNA-101 replaced with a rotary encoder, nanovna has which version of the firmware to support this function
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Which version of the firmware supports rotary encoders
At present, this toggle switch, always feels not silky enough, not sensitive enough, look at the latest version of DEEPVNA-101 replaced with a rotary encoder, nanovna has which version of the firmware to support this function
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Re: where is the end fed natural resonance
On Sat, Mar 2, 2024 at 03:13 PM, Stan Dye wrote:
If you read along in his description, he shows his calculated resonant
frequencies of the choke for different versions of the antenna in a table.
He notes that it should be resonant a bit below the band for a wider-band
antenna response, and close to the lower band edge for a narrow band
antenna.
The way I'd design this antenna is to resonate the choke at the frequency of interest. That will minimize unwanted current on the feedline below. I'd calculate the necessary coil length and number of turns. Using a test coil, I'd adjust one or the other for resonance with a NanoVNA and the Y21 method: Note that PVC and ABS are not the best coil form materials. PEX is less lossy. Styrofoam has negligible loss, but it may not be strong enough mechanically and might also capture moisture. Then I'd duplicate the test coil in the actual antenna and adjust the dipole dimensions for minimum SWR at the target frequency. Unless I needed to minimize the size and weight of a portable antenna, I'd probably add a second choke a quarter wavelength below the first to suppress any residual current. If the feedline drops straight below the dipole for some distance, all this should result in low common-mode current and a clean radiation pattern. Brian
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Re: RF output from nanoVNA-H and H4
On Thu, Feb 29, 2024 at 05:45 AM, montanaaardvark wrote:
A related question is what power is acceptable on port 2 (of an H4)? I have an
LNA I wanted to measure the gain of but not having a large selection of
attenuators I was afraid to do that. It has 24 dB gain and I'm pretty sure any
of those increased by 24 dB (if the amp could put that out without
compressing) could be an issue.
I'm sure I should know this, but I don't.
If you want to measure the gain of an amplifier vs frequency using a NanoVNA you need an attenuator on Port 1 so that the power is limited into the LNA. This serves two purposes: the LNA is not driven into compression and the power out of the LNA into Port 2 of the NanoVNA is at a safe level to prevent damage. You don't want use too large an attenuator because of the limited dynamic range of the NanoVNA. I suggest you use one that is slightly larger than the maximum gain of the LNA. When you calibrate the NanoVNA do the short open and load in the normal fashion but attach the attenuator to Port 1 (or the end of the connecting ) cable when you do the through calibration. Then make your measurement and now the NanoVNA will automatically show the gain vs frequency. Attached are some measurements I made on a Chinese LNA module I bought off Amazon. Roger
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Re: where is the end fed natural resonance
If you read along in his description, he shows his calculated resonant
frequencies of the choke for different versions of the antenna in a table.
He notes that it should be resonant a bit below the band for a wider-band
antenna response, and close to the lower band edge for a narrow band
antenna.
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On Sat, Mar 2, 2024, 2:09 PM Brian Beezley <k6sti@...> wrote: On Sat, Mar 2, 2024 at 12:45 PM, W0LEV wrote:
Thanks for measuring.
That was a calculation, not a measurement. SRF is notoriously difficult to
calculate accurately. I wouldn't read anything into the fact that it came
out exactly 144 MHz. This is where a NanoVNA comes in, especially using the
Y21 method for series measurement.
Brian
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Both files are identical, -H.dfu is always the link to the latest version.
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Re: where is the end fed natural resonance
On Sat, Mar 2, 2024 at 12:45 PM, W0LEV wrote:
Thanks for measuring.
That was a calculation, not a measurement. SRF is notoriously difficult to calculate accurately. I wouldn't read anything into the fact that it came out exactly 144 MHz. This is where a NanoVNA comes in, especially using the Y21 method for series measurement. Brian
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Re: where is the end fed natural resonance
Yes, indeed, it is resonant! Pictures on a PC screen can be pretty
misleading. I should have laid out the dimensions on a piece of paper.
Thanks for measuring.
Dave - W?LEV
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On Sat, Mar 2, 2024 at 8:29?PM Brian Beezley <k6sti@...> wrote: On Sat, Mar 2, 2024 at 12:00 PM, W0LEV wrote:
No need to adjust the resonance of the base inductor as that just forms
an
inductive choke which presents a high-Z at the operating frequency. It is
a reflective choke. Ideally, it would be parallel resonant at the
operating frequency, but the number of turns shown in the link to the
Flower Pot Antenna for 2-meters is far too many for parallel resonance.
It's resonant, Dave. The impedance needed for isolation at the end of a
dipole is very high since the dipole impedance there is high. This requires
a resonant choke.
Just for fun I modeled the 2m choke to see its SRF. I just guessed at the
diameter of RG-58 and I didn't include any adjustment for the outer cover
dielectric. Here's what I got:
Brian
-- *Dave - W?LEV*
--
Dave - W?LEV
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Re: where is the end fed natural resonance
On Sat, Mar 2, 2024 at 12:00 PM, W0LEV wrote:
No need to adjust the resonance of the base inductor as that just forms an
inductive choke which presents a high-Z at the operating frequency. It is
a reflective choke. Ideally, it would be parallel resonant at the
operating frequency, but the number of turns shown in the link to the
Flower Pot Antenna for 2-meters is far too many for parallel resonance.
It's resonant, Dave. The impedance needed for isolation at the end of a dipole is very high since the dipole impedance there is high. This requires a resonant choke. Just for fun I modeled the 2m choke to see its SRF. I just guessed at the diameter of RG-58 and I didn't include any adjustment for the outer cover dielectric. Here's what I got: Brian
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Roger Need
Ho-Ro
