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Re: New version of NanoVNA-Saver: 0.2.1
On Sat, Dec 7, 2019 at 03:54 PM, Kurt Poulsen wrote:
Hello Kurt, Thank you very much for your quick answer. I have 3 questions: 1. Where did you subtract the length (20 cm) ? 2. Did you mean that the S11 phase oscillation curve (about sinus) horizontal center line should be minimised to a straight line and not be bowed? 3. Did you mean with the change of Z0 to connect a resistor of 50 Ohm at the end of the 22 cm coax cable? And then vary this resistor in 0.1 Ohm steps to minimise the amplitude of the phase oscillation amplitude? I mean your file "NanoVNA supplied cable 50K to 500MHz.png" in post 7877 at 2019-12-05 20:10. In this screen shot there are 2 diagrams with S11 Phase. When I try to get a similar diagram with a 30 cm RG174 coax cable with open end I get see attached screen shot nanoVNA-saver_RG174-30cm-open-end.png 73, Rudi DL5FA |
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Re: New version of NanoVNA-Saver: 0.2.1
Hello Rudy
Regarding the impedance issue i did look at the phase oscillation from 0.5 to 500MHz when I in the ZPLots has subtracted the length where the Phase approaches a straight line with oscillations. Then I change the ZO on either side off 50 ohm in steps of 0.1 ohm and for 51.4 ohm the phase oscillation was minimized. The return loss oscillation is not changed by changing the Z0 but rather due to port mismatch. I have 3 NanoVNA's and I just picked a random which I measured as shown and it is longer than the one I mentioned in the previous post. The two cables I got delivered with the NanoVNA-H in enclosure has test cable of 23cm between calibration planes and I did not measure the accurate length before now. Regarding the comment about nanoVNA-saver screen shots I do not catch what you refer to versus "NanoVNA supplied cable 50K to 500MHz.png" It is something I have supplied or what ? Regarding the problems with space versus underscore I do know but for old pdf files I cannot change as links are made in may document. I a slowly changing my behavior. Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] <[email protected]> P? vegne af reuterr@... Sendt: 7. december 2019 14:31 Til: [email protected] Emne: Re: [nanovna-users] New version of NanoVNA-Saver: 0.2.1 On Thu, Dec 5, 2019 at 08:10 PM, Kurt Poulsen wrote: Hello Kurt, Thank you very much for your interesting comparison of the two coax cables. Unfortunately I could not understand by which parameter you conclude that the 20 cm NanoVNA supplied cable (RG174?) does *not* have 50 Ohm. Do you please have a more detailed explanation for that assumption? In your posting 7937 (2019-12-06 23:04) you appended the file: "Measurements of test cables.pdf" you wrote also about a 33 cm NanoVNA supplied cable (RG174?). Is that the same coax cable like to 20 cm NanoVNA supplied cable (RG174?) you mentioned in post 7877 ? By the way, the nanoVNA-saver screen shots in x=1024 pixel size are very difficult to read by me (NanoVNA supplied cable 50K to 500MHz.png). I am using a font size of 11 pt and a x width of about 1600 pixel. If you replace in the PDF file names the SPACE characters by an underscore it will give less problems in a web link. 73, Rudi DL5FA |
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Installing NanoVna-Saver : First Time Problems/Fixes
When attempting to install and run nanovna-saver on my old win-7 laptop, there were two specifically related problems:
1. missing: api-ms-win-core-timezone-I1-1-0.dll 2. missing: Microsoft VC++ Redistributable library Both for Program Files (x86) [as I discovered] Did some on-line searching for the first one and found warnings to make sure the DLL was valid...ooops?? It occurred to me that the DLL might be used by other installed software and it was. Had to be valid** so I CTRL-dragged a copy to the Windows/sysWOW64 folder, ---That took care of problem 1. Problem 2 needed more help and a message to the group with a reply by Rune Broberg led me to the Microsoft VC++ Redistributable library. I found that from Microsoft Downloads: Downloaded it, ran it, and problem 2 was fixed. So now I have the software running and all I need is the VNA...8^)...That's on order for delivery around the end of December. In the mean-time doing some reading. Thanks to Rune for the assist in getting thing going!! ** I'd been running the associated programs for several years so the conclusion the DLL was good -- Chuck, W5USJ |
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Re: USB cable
The picture below shows the ST-Link V2 connector to be routed to a pin row. When you use it with one of your fingers, you gently press it when you are programming. No need to solder.
This was the first time I needed this and it worked right away. The RST cable is not needed here. 73, Gyula HA3HZ |
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Re: New version of NanoVNA-Saver: 0.2.1
Hi Eric and Ady
There is also the lazy way if you know what type of cable you have between equipment and the antenna Use a time domain method to find the cable length (You need to know the cable VF) and then measure with the NanoVNA from the equipment into the cable save as s1p and import to ZPlot. The transpose the length of cable towards antenna and remember to select the cable type and you see the antenna impedance compensated for loss in the cable. Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] <[email protected]> P? vegne af erik@... Sendt: 6. december 2019 17:38 Til: [email protected] Emne: Re: [nanovna-users] New version of NanoVNA-Saver: 0.2.1 I'm not an expert but this is what I understood: Zplot is able to determine the impedance of the feed cable (if different from pure 50ohm) It also is able to calculate the frequency dependent loss This will help you understand what power goes into the cable and what into the antenna. When you calibrate at the end of the feedline you ignore the cable. When ignoring the cable (apart from the compensated delay) is ok, calibration at the end of the feedline is ok -- NanoVNA Wiki: /g/nanovna-users/wiki/home NanoVNA Files: /g/nanovna-users/files Erik, PD0EK |
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Re: New version of NanoVNA-Saver: 0.2.1
Hi pgc1683 (do you have a name or are you an alient ?)
I have repeated the measurement for sending you some s1p files. I have also made a report where the measurement are seen and exposed to ZPlot. Instead of implementing anything in the NanoVNA saver it is much simpler to save to s1p and import in ZPlot followed by a delay which is standard for ZPlot with selection of the cable types in question For the VNWA software there is a simple interface to ZPlots where the measurement are automatic polled to the ZPlots I respond to you questions below -----Oprindelig meddelelse----- Fra: [email protected] <[email protected]> P? vegne af pgc1682@... Sendt: 6. december 2019 14:37 Til: [email protected] Emne: Re: [nanovna-users] New version of NanoVNA-Saver: 0.2.1 Hi Kurt and others, Sorry for wrong copied new post. I deleted it. Now the the correct reply: Thanks for the detailed reply. You can send to me the measurements in file s1p format? You can measure this with professional grade VNA and export s1p format? I frequently use zplots and sim smith chart ( ). Both program useful function extensions for vna-s. Many amateur grade instrument not have useful functions (Markers, cursors, graphs, etc.). I like nanovna-saver, many function available without external program. Some amateur grade commercials vna says: Laboratory grade. This is not true, i test the R&S entry level (!) handheld vna, much better. Of course, many bad connector, adapters, cables exist. For example, my unkown (i think, Hugen, but not 100%) clone nanovna sma thru adapter very bad. Very lossy and not 50 ohm. I have another sma thru, much better. Near ideal with nanovna. <<<Yes indeed the FF adaptor is very poor but from end November Alababa.com supply Hugen-H with low loss FF adaptor anf I have one it is very good See my document for calibration data: and female calibration NanoVNA-H.pdf Professional adapters and calibration kit have low loss. I see many cheap adapter lossy. I think, this erros maybe compensatable. But easiest way change to good adapter. I use lossy port extension trick on low frequncy (if osl calibration impossible), 1,8Mhz to 52 mhz. I not understand square wave signal how many bad. I think not good. Harmonics, for example. <<< In principal terms the squarewave signal does not harm as mixed to an audio bandwith IF %KHz as I remember Another questions, the calibrations. Nanova-saver see raw input values? Or selectable? I think not, use only 101 point nanovna calibration. This is bad for expert user, double calibrations. And 101*10 = 1010 point data, interpolate between 101 original calibration points not a best way. I think some ripple from this way, but i will test it. Professional instrument not recommended to use interpolated calibration point. If change frequency range, it works, but displayed the "uncalibrated" warning. <<<< as all SOL standard has smooth running impedances traces 101 point are enough point and the interpolation is very close to exact calibration. NanoVNA does not use raw data but does small changes to the NanoVNA calibration. That is why you always must calibrate the NanoVNA with same setup of test cables and do a full calibration followed by a save to C0 Then start using NanoVNA saver and do calibration and measurements: On nanovna, i can not find correct calibration. For example open short load delays not user definable. I have not zero lenght N osl calibration kit. Not all sma short has zero delay. I think requres firmware mod. <<< the NanoVNA requires ideal calibration standard meaning open (precompensated with 50fF or 2.5ps one way) 0ps short and pure 50 ohm load. It does not matter whether this is SMA as the supplied kit or N, BNC or PL259 etc. But the trouble is such devices does not exist apart from N female short. But there is a simple stunt to do as when using N, BNC, PL259 flange adaptor the grind down the center conductor flush with the rear side for open. Solder a 2 mm Cu or Brass disk to the center conductor and the rear for short and for open use a single 49.9 ohm 1% SMD resistor as load (in the NanoVNA-saver you need anyway to create a calibration kit file and the define load as 49.9ohm) else use two 100 ohm 1% SMD resistor and in both cases grind down the center conductor to a 0.5mm height. Now you have to figure out the fringe C for the open and the shunt C for the load. More on that later but in the nanoVNA calibration kit file it is "forbidden" to use shunt C for load so the shunt C must be converted to a negative inductance after the formula L in pH= - C-shunt in fF*2.5. Then the delay from the rear of the bulkhead adaptor to the calibration plane has to be calculated and for that purpose a caliper is used. measure in mm e.g. from the front of the female N down to the calibration plane subtracted from the entire length form front to rear and multiply by 4.79 and you have the one way delay = the offset used in NanoVNA. This way you have a super N kit. The fringe C for load is a bit dependent the amount of solder used but about 150fF and the open fringe C is 80fF Calibrating the VNWA is just using the fabricated N standard and in the NanoVNA enable the negative electrical delay with the calculated adaptor delay. Then the calibration to the rear of the adaptors are pulled back to N adaptors calibration plane. If only the calibration of the NanoVNA prior to using the NanoVNA saver then forget about the Electrical delay as that only facilitate fairly correct measurement using the NanoVNA as standalone without compensating for the fringe C of open and load. If you want to do it the complicated way see my document: to fabricate a N Male and Female calibration kit rev2.pdf Kind regards Kurt |
Kurt Poulsen
Chuck Carpenter
Gyula Molnar
Oristo