On Thu, Aug 25, 2022 at 07:38 AM, Khalid Ibne Masood Khalid wrote:
Hello Everyone,
() My concern is whether this VNA can
talk with nanovna saver or may be with some python program?
This VNA product has its own PC program and they have not published their communication protocol. So it does not work directly with NanoVNA Saver or NanoVNA app. You would have to "sniff" the USB exchange in order to reverse engineer the communications protocol. However it does export industry standard s1p and s2p Touchstone files. You can import these into NanoVNA Saver or NanoVNA app and use the graphing options in these programs. Have you considered using another VNA that has better support like the LiteVNA64 or one of the V2 type products? Roger
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You want a Linux compatible way to calibration from raw data?
You might look at SciKit-RF - a python package that does all the needed calculations, as well as drawing plots/smith charts, etc.
An example of calibration:
some sample code attached below where I'm experimenting with measuring a cable and then using it to extend the reference plane to the end of the cable.
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On Fri, Aug 26, 2022 at 03:35 AM, Nick wrote:
Like the raw data calibration facility. Can this application be built on
linux?
My fork for this App: Autor write it on C++ Builder (Use free Embarcadero? C++Builder) This allow compile application on different platform (Windows, Android, iOS, macOS §Ú Linux) Need use not free RAD Studio
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Khalid,
Unless the manufacturer has claimed this device uses a command structure that is compatible with the NanoVNA & LiteVNA series, you will have to write your own interface routines in NanoSaver.
But - the manufacturer needs to have published the interface command structure (API) in a similar way that the NanoVNA and LiteVNA commands have been published.
Good luck.
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On Fri, Aug 26, 2022 at 06:35 AM, Nick wrote:
Like the raw data calibration facility. Can this application be built on
linux?
Nick, Nanovna-App is opensource and available on github: Feel free to port it over to Linux - if you dare.....;-)
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Like the raw data calibration facility. Can this application be built on linux?
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Ok I am going to give it a try I will flash using nanovna.app (I won't be able to save what I got on the unit now) your firmware that was post a few messages back, and I will use your modded software hopefully then the nanovna.app will work! If not or if I need my display to work, I will re-flash (enter DFU mode using the button way cause the display won't work) with the newest firmware version that is listed on the website.
This is the plan!
Thanks so very much for the help!
ohh i am waiting to hear back about this problem on the other forum just a fyi.
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On LiteVNA (or V2 modded by SD card + my fw) possible dump firmware to card from Expert Settings.
For V2Plus4 only if use ST-link.
After hold button and power on, you see only black screen, but on NanoVNA-App or QT connect to device it ask about flash firmware.
After complete possible need power off and power on device.
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Yes I found it in the menu, and when doing the hold right button the display won't say DFU mode just a white blank screen correct?
I won't be doing the ST-link programmer way :( I was hoping there was a way with just software like is done when flashing
I can use the nanovna.app for flashing, correct?
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You found menu 'enter in DFU mode' on V2Plus4 device? Or no?
For enter in Bootload mode (used in device CPU not have DFU mode, it use bootloader) need hold right button (if connectors up) and power on device
PS be careful on use ST-Link programmer for write firmware (use only QT or NanoVNA-App), at start adress written bootloader, this boodloader use CPU unique ID for run, and if damage it you brick device.
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I was just thinking if by loading that firmeware and the LCD don't work then it would be hard to get unit into DFU mode? unless there is a way with using the buttons?
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ya, that's what I am thinking to, I can load stock firmware back if you need. I did post in other forum too.
I can use the nanovna.app to load firmware it does detect when it's in DFU mode, so I would think it's ok for that?
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As i know all (but not LCD module) work, you always can load last firmware from official page for restore.
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hummm maybe i am missing something it won't let me join that forum :(
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Ok that's is good to know i will ask them. you was saying about the display unit could be newer, what would happen if i load your firmware onto a "new" display model? if by doing that the display has issues that is ok cause i would be using the app for measuring and i could flash it back to the stock firmware if i need to.
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I do not track the development of these devices, the developer asked to leave support. Therefore, it is better to ask him on the site /g/NanoVNAV2Firmware for the device that I have posted, but later their hardware changed (or the display connection, I don¡¯t know), so you should still ask the official manufacturer about any device support. But knowing his attitude, I don¡¯t think that anything will come of it (it is for this reason that NanoVNA-App does not support the exchange protocol, the developer did not want to fix some of the nuances in the exchange, saying that these are software problems)
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Ohh, I need hardware too? And it's only part of the firmware?
My has firmware version 20220301 if that tells you anything?
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Re: Antenna Gain measurement with NanoVNA
Seems to me you are conflating reactance with resistance.
0 reactance by definition is the resonant point.? Has nothing to do with resistance or VSWR directly.? Resistance and subsequently VSWR are dependent on both reactance and resistance
Using EZNEC Pro/2 v7.0 and the Dipole1.ez entry I see Z 70.8 and -j6.577 for minimum SWR of 1.43 at 297MHz (I did adjust the element lengths to 0.24 to match the intended frequency better)
However at 299Mhz it shows Z 71.89 and +j0.345 for an SWR 1.44 with almost no reactance so more "resonant" but a slightly higher Z.
And if you change to 75Om Z0 the minimum VSWR shows at 299 instead of 297 with an SWR of 1.043
So once you know your 0 reactance point is all about matching Z to maximize power to the antenna.
Mike W9MDB
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On Thursday, August 25, 2022 at 09:37:56 AM CDT, TG Frerichs <tomfrerichs@...> wrote:
I keep seeing the statement that a resonant halfwave center fed dipole has zero reactance at the feed point, and I don't think this is always correct.
For a center-fed dipole that is 1/2 wavelength and where the length/diameter ratio is greater than fifteen (i.e. a wire antenna) in free space, (e.g., no mutual impedance from a ground plane), I found a couple of references that indicate Xl <> -Xc. They agree as to values.
Quoting Blake:
The radiation resistance for an exactly half-wavelength dipole is found ... to be 73.1 ohms, referred to the maximum current point (dipole center). Therefore this is also the resistive component of the input impedance when the dipole is fed at the center. There is also a small reactive component of 42.5 ohms, inductive. This small inductive reactance may be eliminated by shortening the dipole to about 95% of a half-wavelength (i.e., to 0.475 {lamda}) The radiation resistance (and input impedance) is then 67 ohms. The pattern (beamwidth and gain) is not significantly affected by this slight shortening.? ----? Blake, L. V., Antennas (Second), Artech House, Dedham, MA, 1984, pp. 175-176
And in the Antenna Engineering Handbook (Third) in the chapter on dipoles and monopoles I found a third-order polynomial that gave the same results given the above limitations. The claimed accuracy of this approximation is 0.5 ohms, and in the table entitled "Functions R(kl) and X(kl) Contained in the Formula of the Input Impedance of a Center-Driven Cylindrical Antenna" the values for pi/2 length (in radians) are R=73.12 and X=42.46.? ? ----? Chen, To Tai and Long, Stuart A.,"Dipoles and Monopoles," Antenna Engineering Handbook (Third), Johnson, Richard C., Editor, McGraw-Hill, New York, NY, 1993, pp. 4-4, 4-5
Of course, if you start to include a ground plane, ideal or otherwise, these numbers go all to hell. But I think it does show that assuming that a resonant dipole has zero input reactance is not necessarily accurate.
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Re: Antenna Gain measurement with NanoVNA
Point well said, bravo, thanks Jim.
Mike C.
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On 8/25/2022 11:08 AM, Jim Lux wrote: On 8/24/22 11:39 AM, TG Frerichs wrote:
I keep seeing the statement that a resonant halfwave center fed dipole has zero reactance at the feed point, and I don't think this is always correct.
? <snip>
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Roger Need
Mike C.