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discussion about vna software
#calibration
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Can someone give me a link to discussions regarding the VNA software that's listed in the files section? I posted a question about it on this forum a while ago and I got no comments at all. So I am thinking this topic is discussed elsewhere. In particular I have some questions about the calibration procedure.
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OK. Since you didn't get any answers on your previous post, I'll respond.
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Specifically, what are you calibration procedure questions? I'll try and answer them. Dave - W?LEV On Thu, Jul 9, 2020 at 7:22 PM diyer <m240zz@...> wrote:
Can someone give me a link to discussions regarding the VNA software --
*Dave - W?LEV* *Just Let Darwin Work* |
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vaclav_sal
From reading the mail in past few month - this group is mostly about "how do I ..."
The "software" discussion are generally about how bad is the recent batch of clones. There really is not a dedicated group to actually discuss or , heavens forbid, modify the software. Case of point - when I first learn about NanoVNA I expressed interest in adding bluetooth. It did not go well until I realized what are this group interests. Back to your question - as far as I know the original software is written in C and there WAS an access to source code - few month back. I did imported it from github but couldn't not get my brain to work with the OS it was written for - without having the actually hardware. Dropped the "project" and experimented with bluetooth. I MAY try it again since I got the real McCoy hardware now. Sorry, but I really cannot offer specific about the files. Unless you are seasoned Python hacker, I would stay away from anything Python. ( I loaded chirp - a python app - and lost access to "terminal " - fun ) Cheers |
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I have the original with small screed, the -F and the -H4. All calibrate
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fine using the touch screen, however, I'd recommend using NANOSaver supported on a PC or laptop. You can obtain finer resolution by invoking more points and the procedure guides you through the procedure. Either procedure guides you through the necessary steps. Just remember, before you do a cal. on the NANO only, clear all cals. previously completed. Dave - W?LEV On Thu, Jul 9, 2020 at 7:56 PM CT2FZI <ct2fzi@...> wrote:
Ok we are here to help. --
*Dave - W?LEV* *Just Let Darwin Work* |
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Thank you Dave. Here is the thing I don't understand about using the vnr4 software on our cute little vna tool. First let me say that for now all I'm interested in is less that 20mhz so these little variations that are a big deal above 100mhz don't really bother me.
When I read the PDF for the TAPR-TenTec I see 2 different calibration procedures. 1. Detector calibration. This requires coax cables shorted and open and 50 ohm load. 2. Then there is fixture calibration that seems to require the same thing but with those little sma devices that came with it. It seems like with the our little VNA device if I only do #2 then it should be adequate, since usually the fixture is essentially the connectors on the VNA device or just very very short cables like 1 inch in my case.. Why can't I just skip #1? Is #1 procedure a gross calibration that must be done to get the device and software in the same ballpark? maybe there is a lot of variation of devices? Bottom line What's the purpose of #1 with the software since you don't do that when using the device standalone without a pc. Not looking to reprogram, recompile or any of that other fun stuff. Just trying to understand the process. tks 73 |
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If you are considering covering only to 20 or even 30 MHz, you really don't
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need to distinguish between the "no fixture" and "with fixture". The fixture will make such an insignificant difference at those frequencies it really isn't worth using. All that said, for your target frequency range, do which ever cal you wish and store it. For either cal, you need to use the open, short, and load (SOL) SMA standards that came with your VNA. They are cal. standards. Each time you change frequency ranges, you need to do a cal. Remember, you only have 101 points in the native NANO. So, if you set your frequency sweep to cover 1 through 30 MHz, your resolution or sample spacing will be only every (roughly) 300 kHz. You may totally miss the entire 40-meter band and have only a couple of points on 75/80-meters. So, choose your frequency sweep width carefully. If you set your sweep to cover 6.5 through 7.5 MHz, you would have a sample every (roughly) 10 kHz. In any case, you need to do an SOL cal every time you turn on the VNA. Using NANOVNASaver supported on a PC or laptop, you can save cal. files on the PC. You can also gain many more points by dividing up your total frequency sweep into a number of segments, each of which can accommodate 101 points. Hope this helps a bit? Dave - W?LEV On Fri, Jul 10, 2020 at 12:00 AM diyer <m240zz@...> wrote:
Thank you Dave. Here is the thing I don't understand about using the vnr4 --
*Dave - W?LEV* *Just Let Darwin Work* |
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yes, that does, it is helpful to understand how the number of points and segments affects the stimulus frequencies.
I see that you are just using the pc software to save the cals. I was hoping that I could use the pc software to make nice plots on the pc screen so I could copy and save them. It sounds like I"m not configuring the pc software correctly to make the plots that I'd like to see. Seems like it would be more powerful than just using the device screen in my hand but maybe not. At least my understanding is correct that it doesn't really matter about the 1, 2 calibration procedures especially at such low frequencies. Procedure 2 is adequate. |
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Unless you buy or build a "fixture", there isn't one to calibrate. It sounds like all you need to do for calibration is the normal, common "OSL" described in the basic instructions for any version of the nano, using the 3 loads included with the device. I made a fixture to adapt alligator clips to my nano, for testing and trying to identify unmarked toroid cores.
But you may bet better graphs by using a different PC software Try NanoVNA Sharp, or NanoVNA Partner, or NanoVNA MODv3. NanoVNASaver is also popular but is Python and will not run on my PC. The 101 samples can be important if you may have narrow, sharp resonance peaks or notches. Try scanning narrower bandwidth ranges, 3 to 5 mHz, then 5 to 8 mHz, and so on, and compare with one wider sweep like 3 to 30 mHz. Doug |
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On Friday 10 July 2020 10:15:01 am DougVL wrote:
I made a fixture to adapt alligator clips to my nano, for testing and trying to identify unmarked ?toroid cores.Having a recently acquired NanoVNA-H4, and having a bunch of unmarked toroid cores (some with windings, some without), I'd sure be interested in hearing more about how you do this... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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On Fri, Jul 10, 2020 at 12:05 PM, Roy J. Tellason, Sr. wrote:
Having a recently acquired NanoVNA-H4, and having a bunch of unmarked toroidTake a look at the wiki for this group and you will see several test fixture links. Also search this group for postings on toroids and measuring inductance. Lots of good info for you... Roger |
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On Friday 10 July 2020 03:17:36 pm OneOfEleven wrote:
You might find this a bit informative Roy ..A bit, I didn't know about that phase stuff. But I already have a component tester and an L-C meter to measure those parts with. From what I've been able to gather regarding toroid cores, the material makes a lot of difference in terms of the frequency range the thing can handle. Beyond that things get a bit fuzzy... It's not clear to me what I'd need to do to characterize these cores. Wind a turn or two of wire and see what the value is? Sounds a bit tedious. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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Thanks for mentioning those other software packages, I did not realize there were so many. I just assumed that the files area contained them all. Regarding fixture I'm doing as you suggested. I picked up a sma cable at a swap meet, cut it down to 1" and put alligator clips on it.
I have a linux machine so I assume I could try nanovnasaver on it.. maybe it would even run on my raspberripi. I know it makes a difference when you get to the ghz but I can't help but be amused by the suggestions to get special torque wrenches to attach those sma connectors. Back to plumbing, my least favorite hobby, at least nothing leaks out and causes a mess. |
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As you probably have found out measuring unknown characteristics of torroids is not so simple. you can go here and get some ideas as to the possible types of materials you may have obtained.
In my case most of the junk torroids I've found have come from low frequency switching power supply applications running in the 100-200khz range and turn out to not be very useful for rf. I just decided to buy a few of several types of cores to see how they worked in some of my rf projects. have fun with it. 73 |
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Hi Roy,
Check my quickie forum search link at the top of the Wiki page and use specific search terms to find out more about testing toroid cores as there are probably over a hundred posts from various members on how they perform that.? Also check posts from Herb, Rudi, Erik, Kurt and other members.? /g/nanovna-users/search?q=toroid+cores On Fri, 10 Jul 2020 at 4:57 PM, Roy J. Tellason, Sr.<roy@...> wrote: On Friday 10 July 2020 03:17:36 pm OneOfEleven wrote: You might find this a bit informative Roy ..A bit,? I didn't know about that phase stuff.? But I already have a component tester and an L-C meter to measure those parts with. From what I've been able to gather regarding toroid cores,? the material makes a lot of difference in terms of the frequency range the thing can handle.? Beyond that things get a bit fuzzy... It's not clear to me what I'd need to do to characterize these cores.? Wind a turn or two of wire and see what the value is?? Sounds a bit tedious. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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On Fri, Jul 10, 2020 at 12:05 PM, Roy J. Tellason, Sr. wrote:
Having a recently acquired NanoVNA-H4, and having a bunch of unmarked toroidTry reading this for some ideas.... /g/nanovna-users/topic/72777666#12315 Roger |
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On Friday 10 July 2020 05:48:10 pm Larry Rothman wrote:
Hi Roy,There's definitely some interesting info there. I wonder why my search didn't turn up anything like that? Oh well, more stuff to pursue... On Fri, 10 Jul 2020 at 4:57 PM, Roy J. Tellason, Sr.<roy@...> wrote: On Friday 10 July 2020 03:17:36 pm OneOfEleven wrote:--You might find this a bit informative Roy ..A bit,? I didn't know about that phase stuff.? But I already have a component tester and an L-C meter to measure those parts with. Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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On Fri, Jul 10, 2020 at 03:05 PM, Roy J. Tellason, Sr. wrote:
Check this link (if it works!) It's supposed to be an article by w6rmk, on his earthlink web site. Which I can't find directly - must have gotten the page thru facebook. Or google "Identifying Mystery Ferrites", which might get you there. Also find a PDF by Owen Duffy, on his web site, the article "A method for estimating the impedance of a ferrite toroidal inductor at RF". Section 3, on the second page, is "Identifying ferrite materials", with a chart. You find the frequency where a 1-turn coil's R=X and get the mix number from the chart. There is a similar (but much shorter) page at I have these articles printed out for easy access when I did some toroid checking. Doug |
CT2FZI
Roger Need
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