Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
Search
NanoVNA newbie having problems with new unit
|
I was gifted a brand new nanoVNA unit which was purchased from eBay. I had difficulty with doing the calibration step because the ut came without a 50 ohm SMA load and female thru connector. I found a BNC terminator and SMA adapter cable plus t-piece which I m using as a barrel connector to attach the 50 ohm load. No ideal, but at least I could in this way complete the calibration steps. However there are a number of problems which I am not sure whether are normal or whether the unit is defective which I would like to ask about.
Firstly, the little rocker switch is very poor and sticks when pushed to the left. Pushing down is temperamental. This is probably already a basis for asking for a replacement. I¡¯m no sure whether the 50 ohm connector should have been included but that would presumably be another. The other issues are less clear. For example, I disabled trace 3 and set a start and stop frequence and saved the config, but when I power back on, the config is lost and I¡¯m back to default settings. If I connect an antenna (airband) and scan from 100MHz to 150MHz I see the dip that indicates its resonant frequency on the top yellow trace, but this shifts about if I put my hand anywhere near the nanoVNA unit so that it becomes impossible to move the pointer to the peak to determine the frequency. I don¡¯t see this happening in either of the three videos that I have watched so far. The SMA to BNC cable that I am using to connect the antenna is about 20cm long and is a standard far east product. Any feedback would be appreciated. If these are easy to fix issues that might be expected given the cost of the product then I am happy to try and fix, otherwise I can arrange to get it sent back to the seller. |
|
subs,
As a newbie the first thing you want to do is check out the "Files" and "Wiki" sub-sections of this group. The icons to access either sub-section is located in the left margin of the page. There is a lot of info that has taken time and effort to assemble. If you don't find the info you are looking for in either of those subsections then try the "Search" button at the top of the page. This group is closing in on 6000 messages and odds are someone else has already "been there, done that". There should probably be a hash tag "Newbie" topic as a lot of users are experienced with antenna analyzers but initially get lost when first trying to use the NanoVNA. A vector network analyzer can be used as an antenna analyzer but because it has so much more capability it has to be set-up correctly to give you the information you want to measure. With an antenna analyzer you turn it on, tune to the frequency of interest and read the results off the display. There is usually only one connector on the antenna analyzer so it pretty obvious where you hook the antenna two. The NanoVNA has two connectors, Ch0 and Ch1. Complex impedance measurements, from which typical antenna measurements are made, are done at Ch0. Transmission measurements are done at Ch1. In order to make accurate complex impedance or transmission measurements you have to ensure the NanoVNA is properly calibrated. There is a ton of information in the Wiki sub-section on performing a calibration. There is also User guides and Menu quick operating guides to show you how to select only the displayed information you want. At first the displayed information is daunting, but with use you learn to get only what you need displayed. As far as your specific questions: 1. A search through the messages for "switch" will show you that the multifunction switch is the least liked feature of the NanoVNA. The primary problem is that is polled rather than interrupt driven. That means the microprocessor doesn't respond as soon as you operate the switch. It may be performing other operations and gets around to checking if there is input from the switch when there is a break in those operations. This causes the operation of the switch to appear "laggy". For menu selection and numerical input, the touchscreen is more of a pleasure to use. The only time I use the switch is for marker movement, as trying to "drag" the markers using the touchscreen can be a chore. Having said all that, if the rocker switch is physically stuck to the left of right when you release it then that is a mechanical problem and I would see to exchange it. 2. You should thoroughly read the user manual on the Wiki subsection on saving and recalling configurations. "Save 0" always holds the configuration information that is displayed when the NanoVNA is powered on. If you changes are not specifically made using "Save 0" then they will not show at power on. 3. I am sure you've heard the term "hand effect". If the antenna is not in close proximity to the NanoVNA and the cable connecting the antenna and the NanoVNA is properly shielded then you shouldn't observe any noticeable "hand effect". If either of those conditions is not true then you will observe the effects of your body detuning the antenna as your hand approaches the NanoVNA. 4. Some of the NanoVNA's are sold without cables or OSL standards to lower their selling price. Is you already have those items then you can cut your cost that way. If you don't have those items then you generally pay more in purchasing them after the fact. Hope you don't get discouraged. Like any other piece of test equipment, the NanoVNA takes time to learn to operate properly. If you have some past measurements on any antennas or other devices, compare that data with the NanoVNA . That is a good check of whether the NanoVNA is operating as it should. - Herb |
|
Thank you for your kind reply. My apologies for not checking out the "Files" and "Wiki" section. It does indeed have a lot of information and contains my answer regarding the issues with the switch and lots more!
Regarding your points: 1. Answered by WiKi. Thanks. 2. I had a look at the file "nanoVNA User Guide 2019-07-11 (PDF)|" but the settings do not correspond to what I have on the device. There is no RECALL/SAVE item, just RECALL under which there are 4 Recall options 0 - 4. Under CONFIG there is just SAVE which I assumed would save the settings. There is no SAVE 0. Under CAL there are SAVE options with SAVE 0 thru SAVE 4 and which I presumed relate to saving calibration setting profiles. It is possible that I need to update my firmware, but having reviewed that information I am totally confused as to which firmware I actually require? There seem to be various versions by different people and I am not sure which one is the de-facto or "official" version? My current firmware version is: 0.2.3-1-g145a034 3. Yes, I am aware of the hand effect. I am using a shielded co-ax only 20cm long so the end of the antenna is approximately that distance away from the nanoVNA. The nanoVNA is also shielded well with metal plates front and back so I didn't expect that to be a problem. The guy in the video was plugging antennas directly into the nanoVNA, handling them and moving them about and yet the traces seemed to be rock steady. On mine, the peaks completely shift away from their position when my hand gets anywhere near the unit so was very prone to the hand effect. Looking at the Hardware Versions section on the WiKi, I believe that I do have the genuine article. I avoided the white version and have a black unit like the genuine one in the picture with NanoVNA written in the bold and with the correct font (no rounded V). On the board, everything seems properly shielded. I haven't yet removed the cellophane from the screen. 4. Thanks for confirming that. I will order in the items that I need. I take your point about the learning curve which is why I was only going through the basics at this stage, i.e. calibration and a quick test following step by step with the help of a video. I just used a couple of my scanner antennas. In time I intend to make a further study. I don't have any other basis for comparison. I was hoping one day to get a spectrum analyser, but can't afford one for now and this nanoVNA should suffice for my present hobbyist needs. Even with the hand effect, I think I have managed to work out the best configuration for my loaded telescopic whip to pick up the frequencies of interest on the scanner, although it would have been much easier and more accurate if the trace remained steady. Incidentally, I tried the Web client on my PC but without success. Firefox just gives a blank screen. With Chromium I was able to get to the web page at and it showed part of the menu with most of the options greyed out and blank frames. When I clicked Connect for the first time it listed a virtual USB device and paired it, but, I then got: "failed to open: Error: failed to open device". Unfortunately there is no troubleshooting info on the authors website and I couldn't find anything more generic elsewhere, for example on Google Chrome or Chromium. There is helpful information telling you how to pair and connect, but not in relation to this error, so any help here would be appreciated. Since I'm on Linux, I will probably also have a look at NanoVNA Saver. John. |
|
John,
Glad you are making progress. The NanoVNA Web client is primarily used by people who want to save data from their NanoVNA while taking measurements in the field or away from their PC. The page by the author, , gives some sparse directions for Linux (Ubuntu). My advice is to go straight to Rune's excellent NanoVNA-saver application. Plenty of users in this group have it working under Linux and will be able to assist you if you have installation problems. The user guide at /g/nanovna-users/files/NanoVNA%20User%20Guide-English-reformat-Oct-2-19.pdf is the most recent English translation of the official on-line help document by cho45. The latest firmware release by hugen at should probably be considered the stable release and other releases later than his as experimental or beta. Hugen eventually merges some all or some of the features of the experimental releases into his master branch. If you are not seeing a proximity effect with your receive antenna then I'm not sure why your measurements are varying when you interact with the NanoVNA. Since you were able to fight through the variations then I'm glad you were able to get things to work out for you. -Herb |
|
It seems then, that the firmware version that I have is the latest by Hugen.
With regards to the Save, thank you for the link, and this one makes more sense as it is consistent with the menu I have. It seems that Trace setting status rather oddly is saved in the calibration settings along with Marker setting status. I just didn't envisage that as a calibration factor. As you pointed out, it needs to be saved in SAVE 0, but under calibration rather than the general system settings SAVE, which doesn't seem to save much except: - Touch panel calibration information - Grid color - Trace color - Calibration data number loaded by default That's sorted that one out. I ran into difficulties with nanovna saver though. I already had the pre-requisistes: `python3-serial` * `python3-pyqt5` * `numpy` The last of these is ambiguous which I will come to in a moment. I followed the process in the readme and got this at the end of the output: ------------------- Running setup.py bdist_wheel for NanoVNASaver ... error Complete output from command /usr/bin/python3.7 -u -c "import setuptools, tokenize;__file__='/tmp/pip-bd9ju62f-build/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /tmp/tmp_eemos37pip-wheel- --python-tag cp37: /usr/lib/python3.7/distutils/dist.py:274: UserWarning: Unknown distribution option: 'long_description_content_type' warnings.warn(msg) usage: -c [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...] or: -c --help [cmd1 cmd2 ...] or: -c --help-commands or: -c cmd --help error: invalid command 'bdist_wheel' ---------------------------------------- Failed building wheel for NanoVNASaver Running setup.py clean for NanoVNASaver Failed to build NanoVNASaver Installing collected packages: PyQt5-sip, PyQt5, numpy, pyserial, NanoVNASaver Running setup.py install for NanoVNASaver ... done Successfully installed NanoVNASaver-0.1.4 PyQt5-5.11.2 PyQt5-sip-4.19.19 numpy-1.17.3 pyserial-3.4 ------------------- I then ran: $ python3.7 nanovna-save.py and got: python3.7: can't open file 'nanovna-save.py': [Errno 2] No such file or directory I had python-numpy installed, but I then tried installing python3-numpy and then ran the install again. This time I still got the same warning at the end of the install output, but the program ran. It would therefore seem that python3-numpy is the required package. The program does seem to connect to the nanoVNA and I was able to set the start and stop frequency and run a scan which seemed to work. However, it would seem that some component has failed. Any help would be appreciated. |
|
Hi John
I had a look at the file "nanoVNA User Guide 2019-07-11 (PDF)|"Here are 3 menu maps for different firmware versions: /g/nanovna-users/wiki/User-Guides Under CONFIG there is just SAVE which I assumed would save the settings.That SAVE is nominally for touch screen calibration. It is possible that I need to update my firmware, but having reviewed that informationUnless you identify problems with firmware you have, other than confusing/missing documentation and poorly organized menus, what you have should be good enough. Recent messages are more likely about recent firmwares. .. for which documentation is more likely outdated. There seem to be various versions by different peopleThat is between 6 and 19 days old, per I have different problems with every version tried. For using nanoVNA standalone, I install Hugen's most recent AA dfu version from here: |
|
Hi,
toggle quoted message
Show quoted text
the file name is "nanovna-saver.py". So the error you got seems to have been because you tried to run a file that did not exist? If the application works, then I don't think anything important has failed. You don't mention which commands you tried running in which order, so I can't tell what caused the "bdist_wheel" problem. -- Rune / 5Q5R On Sat, 26 Oct 2019 at 11:37, <subs@...> wrote:
It seems then, that the firmware version that I have is the latest by |
|
I would also suggest you are too close to the antenna you are trying to
toggle quoted message
Show quoted text
test. With a 20cm cable your body is very close. If you are also testing indoors it can also scew your results. Paul G0VKT On Sat, 26 Oct 2019, 10:56 Rune Broberg, <mihtjel@...> wrote:
Hi, |
|
You might be having a problem with RF currents on the coaxial cable shield and therefore the VNA. You could try putting a ferrite beads on the cable but you would need to remove and reattach one connector. Just as good would be to loop the cable through a ferrite toroidal core a few times. The type of ferrite should be appropriate for the frequency range of concern.
|
|
"I have different problems with every version tried.
For using nanoVNA standalone, I install Hugen's most recent AA dfu version from here: When I fist saw that _AA_ version I thought that a 274kb file would not fit on a 128kb device! I am familiar with Arduino process where we upload .hex files with an AVR programmer so was drawn to that file first. Looking at the manual section 8, I see that I need dfu-utils, which is available in Ubuntu so I can download that and use the .dfu file when a new update is released. For now, since my device has been supplied with the most recent version, I see no reason to change the firmware yet. However, what is the difference between the _AA_version and the non-_AA_ version? "the file name is "nanovna-saver.py". So the error you got seems to have been because you tried to run a file that did not exist?" Yes, absolutely, which suggests that the first time with the python-numpy package installed, the installer did not complete correctly. The second time with python3-numpy installed evidently it did. But that didn't get rid of the "bdist_wheel" problem. Sorry, I had listed all of the commands in my post but a copy and paste error meant that I had to re-type everything in haste. I basically followed the readme exactly. Here are the steps: - unpack the .tar.gz file into a directory - enter the directory - check all dependencies are present $ sudo apt install python3.7 python3-pip $ python3.7 -m pip install . Once completed: $ python3.7 nanovna-saver.py These were present: * `python3-serial` * `python3-pyqt5` This one does not exist: * `numpy` However, python-numpy exists, and I installed python3-numpy for good measure. "I would also suggest you are too close to the antenna you are trying to test. With a 20cm cable your body is very close. If you are also testing indoors it can also scew your results." The guy in the video connected the antenna directly to the SMA connector and had his hands onver the antenna as well as the nanoVNA yet (apparently) had no problems. Maybe some creative editing? I am testing indoors and both antenna and nanoVNA are close to me. I found that if I take note of where the peak is when my hand is away from the unit and then move the marker to approximately that point on the screen and then move my hand away to see here it landed, then eventually with two or three more corrections it I can get the marker pretty close to spot on. I had a closer loor at the unit today. Its seems that the front and back are not made of metal as I had thought, but of thin PCB material. The corners have plated through holes, but there doesn't seem to be any metal layer across the board, so reaaly, there is no outer shielding. The 4 screw mounts are not connected to the ground plane either so any shielding would not have been electically connected anyway. Is this intended by design? I notice that the more expensive version in the black box appears to come in a plastic case? |
|
Spelling the name of the file wrong doesn't suggest a problem with numpy,
toggle quoted message
Show quoted text
no ;-) I don't know exactly what Linux version you are using, but the instructions given normally work, and will install any required dependencies via pip. I hope you manage to get it to work in any case :-) -- Rune / 5Q5R On Sat, 26 Oct 2019 at 16:24, <subs@...> wrote:
"I have different problems with every version tried. |
|
"You might be having a problem with RF currents on the coaxial cable shield and therefore the VNA. You could try putting a ferrite beads on the cable but you would need to remove and reattach one connector. Just as good would be to loop the cable through a ferrite toroidal core a few times. The type of ferrite should be appropriate for the frequency range of concern."
Thank you for this. I will have a think about this. At this stage I am only plugging in the antenna and looking for the dips that show the resonant points. I am not pumping any signal in, but I guess it is possible there might be currents induced from other sourcessuch as CFL lights or chargers. "AA has larger text, but is limited to displaying two traces at a time" Thank you for the explanation. That might actually be helpful on this small screen although if I can get PC software working and learn to work things from there, then it might not be needed. I will experiment some more and see. BTW, I have now logged the "bdist_wheel" issue on the nanovna-saver Github. |
|
W5DXP
From: subs@...: However, what is the difference between the _AA_version and the non-_AA_ version?The AA version is a single-port (CH0) version, i.e. Antenna Analyzer. The CH version is a dual-port version - CH adds CH1, i.e. Vector Network Analyzer. Presumably anything without an AA or CH ID is a dual-port VNA version. |
|
On Sat, Oct 26, 2019 at 09:33 AM, W5DXP wrote:
The AA version is a single-port (CH0) version, i.e. Antenna Analyzer. The CH------------------------------------------------------------------------------------------------------------------------ W5DXP, Referencing the groups Wiki page at: /g/nanovna-users/wiki/home aa / ch : aa (Antenna Analyzer) is limited to 2 traces but larger font size. ch has 4 traces, but smaller font size. My first NanoVNA had the AA firmware installed. Both ports are still activated in the AA firmware but by default the two available traces are set in the menu to CH0 for making reflection only measurements. For making transmission measurements, either trace can be set to CH1. By limiting the unit to two traces the memory savings was used for a larger font size. The CH version can be put in a mode similar to the AA version by turning off two of the four traces and assigning the displayed traces to CH0 for making reflection only measurements. In the foregoing display configuration, the font size is smaller for the CH version of the firmware. - Herb |
|
"The AA version is a single-port (CH0) version, i.e. Antenna Analyzer. The CH version is a dual-port version - CH adds CH1, i.e. Vector Network Analyzer. Presumably anything without an AA or CH ID is a dual-port VNA version."
"My first NanoVNA had the AA firmware installed. Both ports are still activated in the AA firmware but by default the two available traces are set in the menu to CH0 for making reflection only measurements. For making transmission measurements, either trace can be set to CH1. By limiting the unit to two traces the memory savings was used for a larger font size." W5DXP and hwalker, and Larry Rothman, thank you for this further clarification. Not having the option to inject a signal from one channel while listening to the other might be an issue if this was specifically required for testing and would certainly be a considration when choosing the firmware version. However, if one of the traces can indeed be assigned to CH1 for transmission measurements, then that is less of an issue. Two channels are sacrificed to get a bigger font. I guess it depends on whether the measurements being done will require more than two traces and whether one doesn't mind the smaller font. I will stick to the version I have for now. BTW, I have now ordered the 50ohm load, female SMA through and other adapters as well as a fine touch stylus. These will take some time to arrive, but hopefully will make things easier to to complete the calibration properly without additional leads and adapters. |
|
Thanks, and I take your point and I acknowledge that I probably made a typo the first time I ran 'python3.7 nanovna-saver.py' to run nanovna-saver. I had evidently missed the final 'r' off, perhaps while copy and pasting it. However, the 'bdist_wheel' thing happens either way. As mentioned, I have this logged on their Gitub and mihtjel has kindly said that he will look into it, although he also confirmed that no functionality would be missing.
Regading the dependencies, with the exception of listing them, there are no instructions given for the download/install of them, including this one. This is not unusual as it is usually left to the user to figure that out. PIP seems to be being used only to install the nanovna-saver package. On Debian and derivatives (Ubuntu/Mint) the way to install these dependencies would usually be e.g. "sudo apt install numpy", but that does not work as there is no such package. I also imagine that there is likely a difference between the package that I already had installed and initially tried to run against, namely 'python-numpy' and the one named 'python3-numpy'. They look like different versions of this python module and I now have both installed. However I agree, that this doesn't mean that there is a problem with numpy per se, only that the instruction, as stated in both the downloaded nanovna-saver README.md and on their Github is ambiguous and I just wanted to bring that to attention in case anyone else who has little Linux experience runs into the same problem. I did a couple of tests by removing python3-numpy, and running nanovna-saver with python-numpy and it seemed to run OK. I then did the opposite and removed python-numpy and then re-installed python3-numpy. Nanovna-saver also seemed to run OK with this version, so perhaps the program does not seem to mind which version is installed, so long as at least one of them is. Python3-numpy would seem to be more consistent with the version of the other two python dependencies mentioned, i.e. python3-serial and python3-pyqt5 but I will wait to see what mihtjel advises. |
|
Hi John-
toggle quoted message
Show quoted text
In your #3, what you're seeing should be due to the fact that the antenna-VNA assembly is "floating" and is highly subject to things that are in the near field. Basically, anything that is not virtually invisible to RF (like teflon, etc) becomes part of the antenna system when it is in the near field and when (for example) your hand comes very close to, or actually in contact with any part of the antenna-VNA assembly, you become part of the antenna system. Any "shielding" that is only connected to the shield side of the antenna or the "ground" trace on the analyzer's PCB just becomes part of the antenna system as well. That alters the impedance seen by the VNA, and that is reflected in what you see on the display. This is why designing/evaluating antennas for handheld transceivers is such an "interesting" process! Hope that makes sense! Very 73 Tom On Fri, Oct 25, 2019 at 08:37 PM, <subs@...> wrote:
|
Oristo
Gary W9TD
to navigate to use esc to dismiss