NanoVNA - tried to do my homework, more confused than ever. - Page 1
Forum section: electronics / rf-microwave

author: casterle
author_rank: Regular Contributor
timestamp: December 26, 2020, 06:58:00 am
content: In advance, thank you for your time and patience in helping an old hobbyist, new to the RF arena, with some needed advise.I've found bits and pieces of what I'm about to ask scattered about, but nothing that addresses my question. Referrals to answers I may have missed are most welcome!I've spent a few weeks here and on YouTube trying to identify an inexpensive VNA that meets my needs as listed below. I've decided that my best option lies within the NanoVNA-ish family of products,but if you think I should consider something else, I would appreciate your input.I usually like choices, but this device takes the concept to the extreme, or so it seems to me. Part of my frustration lies with the nebulous nature of these devices; several times I've followed links to the recommended device, credit card in hand, only to find something else, or a device no longer carried/produced.On to myneeds:Reliable & accurateLow KHz to >= 3 GHzActive firmware/software/support community, preferably with a history of making reasonable efforts to fit fixes and improvements to prior versions. Extra credit for multiple active options for firmware.PC connectivity for data export & remote controlPrefer < $100, but could go to $200 (US)As my old eyes no longer play well with small screens, I'd prefer one of the larger devices, but small is fine if it best meets my other criteriaAnd mywants:Range to 6 GHz so when my wireless devices finally support 5-gig I won't need something new.Whatever my ignorance has led me to omit from this list, barring cables, connectors and such which I have in abundance.And finally mydon't care:Large battery capacityI've found 3 form-factors, each with either a 2.8(?)", 4" or 4.3" display. Within each of these groups lie many devices:With or without plastic or metal casesWith or without accessories, which themselves vary in quantity and appearanceWith varying names, color combinations and logosWith varying claims of functionalityWithoutindication of what may differentiate each from the otherSo I am left to wonder...Are these 3 devices each designed/manufactured by one company, then sold to and rebranded by others such that all hardware within each group is identical and usesor can usethe same firmware/software?Are some resellers supplying/installing some/all of the critical components such that devices using the same board from the same source may perform differently?Something else?So now I hope you understand why I'm frustrated and bewildered. Would some kind soul please suggest a product that I can buy, with some way to know it when I see it?Extra karmafor a link to something I can order today, in stock or out with more on the way, before the darn thing has vanished never to be seen again.Thanks again for being the kind of person who reads these long pleas for help!

author: DH1AKF_Wolfgang
author_rank: Contributor
timestamp: December 26, 2020, 09:41:36 am
content: You need a NanoVNA V2 Plus4.The following site has some links to sellers and specially newsgroups.https://nanorfe.com/nanovna-v2.htmlThis VNA works until 4.4 GHz and has a 4 " display.For 6 GHz your money budget is too small.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 26, 2020, 10:16:50 am
content: in GHz VNA world, > $5000 price is common and considered cheap. few years ago before NanoVNA madness, i was looking for 6GHz speced VNA, my only hope when Deepace KC901V reviewed by Shariar @ $2000, after sitting in ebay for so long waiting for the right price on used VNA (HP) market, i lost patience and hit the KC901V. during the time, i saw 3GHz PC-USB unit for like $400 cheapest and more, i think like MiniVNA, PocketVNA etc, didnt really hit me as i was looking for 6GHz minimum, and PC-dependent unit is less tempting. now came NanoVNA 3GHz, since you limited your budget to $200 you pretty much narrow it to only one brand... NanoVNA... and with V2+4 price raised to $150, i'm expecting the upcoming 6GHz version will be out of your budget too

author: casterle
author_rank: Regular Contributor
timestamp: December 28, 2020, 11:05:03 pm
content: Quote from: Mechatrommer on December 26, 2020, 10:16:50 amThank you. I didn't expect to find a 6 GHz unit in my price range, but hey, until a few months ago I didn't realize I could get a functional multi-component tester/identifier for < $15 so you never know!All I really want is to cover through 2.4G for WiFi IOT stuff. Few offer 5G support yet, and I expect 2.4 will live on long after it's common.

author: cdev
author_rank: Super Contributor
timestamp: December 29, 2020, 01:28:08 pm
content: I have the plain version 2.2 and it offers usable functionality above 3 GHz, for some things. The synthesizer does go up to 4.4 GHz. It can be calibrated normally, but the response (as others have shown here) has ripples but they are not large in the lower part of that range. It does show useful info. (Like the response of a filter or component, or SWR) The (in)accuracy if one goes much higher could likely be characterized using a better instrument and some of it compensated for, perhaps in software?

author: joeqsmith
author_rank: Super Contributor
timestamp: December 30, 2020, 01:16:40 am
content: For the V2+ & +4>Reliable & accurateMy V2+ has not been reliable since purchased. The V2+4 has been working fine but really, for the $130 I'm not expecting a long life out of it.Guessing it will depend how you treat it more than anything.> Low KHz to >= 3 GHzNot sure what low KHz means but I will say the V2+/+4 can not be used for narrow band measurements. I found that out after buying them. Odd is that my original NanoVNA does a decent job.>Active firmware/software/support community, preferably with a history of making reasonable efforts to fit fixes and improvements to prior versions. Extra credit for multiple active options for firmware.I don't have any use for firmware options myself. I just want the raw data, a lot of it and I want it fast. V2+4 does a decent job. So much better than the original NanoVNA. The supplied software, well, it's on par with what I saw with the original NanoVNA. I couldn't use it. I'm sure there are some open source interfaces for it by now.>PC connectivity for data export & remote controlSee above.> Prefer < $100, but could go to $200 (US)$150 ish for the V2+4.> As my old eyes no longer play well with small screens, I'd prefer one of the larger devices, but small is fine if it best meets my other criteriaUse a PC.Based on the lack of requirements, it sounds like a learning adventure. IMO, that really is the strong point of these devices. They are good enough to learn some basics and cheap enough that when you damage them, it's no big deal.I had someone contact me about a used VNA they had for sale. I think they were asking $13 or so. I saw they are down around 7 now with the ecal & cables. That's a good deal assuming the system all checks out.

author: virtualparticles
author_rank: Regular Contributor
timestamp: December 30, 2020, 07:05:50 pm
content: IMHO, none of these small VNA's are what one could call "accurate". For instance, the typical supplied load standard in the cal kit has a return loss of about 15 dB. That means +/- 3 dB accuracy for 5 dB RL measurements which is dreadful. The phase accuracy is nonexistent since the delays of the short and open are not taken into account during calibration. After calibration, all of these units are pretty drifty and if the temp in the room changes or you blow on the circuit board, you can expect a fair amount of change.All this being said, they are probably worth the price for a hobbiest as long as that hobbiest isn't trying to do rocket science. They are a fun toy.Good Luck!

author: Bud
author_rank: Super Contributor
timestamp: December 30, 2020, 07:21:15 pm
content: Inexpensive, good community support, failrly accurate ( including characterization of the cal kits) - take a look at VNWA. Over 10 years of active project with community support, developed by a math professor (and a Ham radio enthusiast) from a German university.

author: Dennis Frie
author_rank: Contributor
timestamp: December 30, 2020, 07:30:46 pm
content: What's the specific use of the instrument? Tuning filters, measuring antennas, smith chart or?I've been playing a bit with a miniVNA Tiny Plus2 (1 MHz - 3 GHz). While it's pretty good for basic antenna measurements, reflection etc. actual antenna tuning using smith chart at higher frequencies, are not exactly what I would call "stable and accurate".As already mentioned, it's a great tool and will get you a long way. Just don't expect too much in terms of accuracy, especially when going to the GHz-range and looking at phase

author: cdev
author_rank: Super Contributor
timestamp: December 30, 2020, 10:15:54 pm
content: Why not?Indications so far are that the nanovna2 is accurate within its specs. Manufacturers of high priced VNAs have conceded this.The uses of the instrument are it seems the same as yours - I suspect the same as most instances of when one would use a much higher priced two port VNA forbut in the hobbyist and ham radio context.So far for me its mostly been tuning filters, adjusting antennas..yup. The smith chart is accurate, especially if you use a higher number of points, its really produces quite useful info.Set to produce so many points requires using it with a computer, and since I have the 2.2 version, its slower, but hell, I'm saving money so I can wait a minute longer!Quote from: Dennis Frie on December 30, 2020, 07:30:46 pmIs it not accurate for phase above 1 GHz?

author: cdev
author_rank: Super Contributor
timestamp: December 30, 2020, 10:30:01 pm
content: I don't understand what you're referring to here, could you flesh this out a bit for a beginner?Quote from: virtualparticles on December 30, 2020, 07:05:50 pm

author: joeqsmith
author_rank: Super Contributor
timestamp: December 31, 2020, 01:35:05 am
content: Quote from: cdev on December 30, 2020, 10:15:54 pmInteresting that the name brand manufactures are even looking at these. Can you provide a link to their reports? Maybe you meant owners of high priced VNAs?Quote from: virtualparticles on December 30, 2020, 07:05:50 pmNot sure about their firmware calibration but it seems like their software supports Touchstone. Assuming you have the data for the standards you plan to use. Sounds like there are two other software packages that support the V2+. They may be willing to add what ever features you want.I'm working on documenting my software as well which basically uses the Agilent format.https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3356252/#msg3356252I've not seen what I would consider a problem with drift with any of these low cost units. If you or anyone else cares to document their findings (test setup etc), I can attempt to replicate it using mine.The loads supplied with the V2+ were an improvement over what I received with the original unit.

author: casterle
author_rank: Regular Contributor
timestamp: December 31, 2020, 04:15:56 am
content: Quote from: joeqsmith on December 30, 2020, 01:16:40 amThat is exactly what I'm looking for - an adventure in learning. I'm about to start exploring the physical world via affordable tools. I'm nearly done packing for the trip!Quote from: joeqsmith on December 30, 2020, 01:16:40 amThanks. I almost asked for more info, but I think I want to start with something new so I know it's solid; I don't know enough to feel safe doing otherwise.

author: casterle
author_rank: Regular Contributor
timestamp: December 31, 2020, 04:25:37 am
content: Quote from: Bud on December 30, 2020, 07:21:15 pmThanks. I took a look, but this product line looks like a technically steeper first step than I'm up for. I'd love to own a German-engineered product; this is the first I've seen that I could afford since the '63 VW Bug I drove in high school many decades ago (probably not what comes to mind when one thinks of German engineering).

author: casterle
author_rank: Regular Contributor
timestamp: December 31, 2020, 04:45:34 am
content: Quote from: Dennis Frie on December 30, 2020, 07:30:46 pmMy one and only purpose in buying this instrument is to learn; it will be an educational toy and if I actually build anything with it that's icing on the cake. I want something as flexible as I can get within my limited budget so I can go in whatever direction my curiosity takes me.Quote from: Dennis Frie on December 30, 2020, 07:30:46 pmI was under the impression that the NanoVNA was quite useful for antenna tuning - that's one area I'm eager to explore. Are you commenting on your specific brand/model of instrument, or do you feel all units in this class fall short like this?

author: DH1AKF_Wolfgang
author_rank: Contributor
timestamp: December 31, 2020, 10:43:40 am
content: Instead of long speechesyou better should asks the users of NanoVNA /V2 /F:https://groups.io/g/nanovna-usershttps://groups.io/g/NanoVNA-V2

author: joeqsmith
author_rank: Super Contributor
timestamp: December 31, 2020, 01:36:23 pm
content: Quote from: casterle on December 31, 2020, 04:15:56 amJust for learning and exploring, I suggest getting both the original NanoVNA and the V2+4. In some cases, the original NanoVNA will out perform the V2+4. Combined, you're in that $200 range. You may want to get one of those demo boards (I havn't played with one).At the $13,000 they were originally asking (even at $7,000), I would just make the sale contingent on the unit being sent in for calibration. If the unit were to fail the seller eats the cost. If it works, you cover it. That extra $1,000 or so may save you a lot of pain. A member here had/s an older 8753 they were selling for I think around $3,000. Looked clean.If you lived next door, I would give you my old 8754A. The cost to ship it could very well exceed your budget.I learned a lot from that old instrument. There's no computer, so it forced me to learn the basic math.If you are strapped for cash, you could save the $200 and just download several free papers and start reading.I tried the mailing lists off and on but never found them particularly helpful. Most of the chatter was amateur/CB radio related (antenna tuning seems to be popular) or someone talking about their printed case. The forums seem to be more focused and easier to search. Some of the mail lists are locked. Imagine, the NanoVNA cult.

author: cdev
author_rank: Super Contributor
timestamp: December 31, 2020, 01:41:00 pm
content: No,This was in either the nanovna2 or the original nanovna group. One of the executives of another manufactuyrer, one that I know but I dont remember which, had one, had looked at in in their lab, and had conceded that it was performing exceptionally well. This was one of the main factors that made me buy it. I had a strong feeling that I better jump on it quick.I don't have a link, I don't think. But its in there if you look.Quote from: joeqsmith on December 31, 2020, 01:35:05 am

author: casterle
author_rank: Regular Contributor
timestamp: January 01, 2021, 01:30:42 am
content: Quote from: joeqsmith on December 31, 2020, 01:36:23 pmI think you omitted the ',000' in the original message. I thought we were talking about a used NanoVNA here! I'd have to sell my neighbor's car to get into that price range.Quote from: joeqsmith on December 31, 2020, 01:36:23 pmI've been unable to find what I'm sure is arealV4+2 available for order; I'm on the manufacturer's waiting list. I think I'll grab a NanoVNA while I'm waiting. Am I looking for something called exactly NanoVNA with no adornments or qualifiers on the name? Can you suggest where I might buy one that isn't a cheap knockoff?If I'm confused, it's that I've found units that look alike with different names, units that look different with the same name and other trust-depleting red flags. Thanks!

author: cdev
author_rank: Super Contributor
timestamp: January 01, 2021, 03:24:48 am
content: I was told it was worth waiting to get a nanovna2, and I did, and I'm very happy that I did. I got the SAA2 from the makers on tindie .

author: virtualparticles
author_rank: Regular Contributor
timestamp: January 01, 2021, 03:33:40 am
content: Quote from: cdev on December 30, 2020, 10:30:01 pmHere is an interesting video which covers reflection measurement accuracy. JoeQSmith posted that touchstone files might be used to data base the calibration pieces. I wasn't aware of that. If so, that would be very helpful for the accuracy of the device. Most mechanical calibration kits simply assume that the 50 ohm load is perfect and the open and short are characterized by a third order polynomial over frequency plus a delay. One would need a "real" VNA to characterize the calibration pieces and generate the touchstone files unless they are already supplied.Please see this short video for an explanation of reflection measurement uncertainty.https://coppermountaintech.com/reflection-vs-transmission-accuracy-in-vector-network-analyzer-measurement/Cdev stated that the NanoV2 is accurate within it's specs. Could you share those specs please? My orginal Nano came with none at all. I'd be really curious.Thanks!Brian

author: virtualparticles
author_rank: Regular Contributor
timestamp: January 01, 2021, 03:36:33 am
content: Quote from: cdev on December 30, 2020, 10:15:54 pmCould you post the specs please? Mine didn't come with any at all.

author: cdev
author_rank: Super Contributor
timestamp: January 01, 2021, 03:44:27 am
content: They have a chart on their web site.https://nanorfe.com/nanovna-v2.html#specificationsHonestly, I think its literally the best deal in test equipment I've ever gotten. Its certainly been getting a lot of use. It basically lives on my desk now.

author: virtualparticles
author_rank: Regular Contributor
timestamp: January 01, 2021, 04:08:14 am
content: Quote from: cdev on January 01, 2021, 03:44:27 amThanks for the speedy reply! I believe the VNA probably meets those "specifications". They don't actually give any accuracy specs at all so to that's pretty easy to say! The system dynamic range tells you something about S21 accuracy at low levels but the accuracy from 0 dB down to about 50 dB would be a function of transmission tracking error which is not given. The "S11 Noise Floor" is completely meaningless. Reflection accuracy is a function of the residual directivity of the VNA which is mostly determined by the uncertainty of the load in the cal kit, not the "noise floor" of the reflection receiver. See the video I posted earlier for details.I'm glad you're happy with the device, I totally agree that for that price, everyone should have one to play with.Thanks!Brian

author: casterle
author_rank: Regular Contributor
timestamp: January 01, 2021, 06:52:16 am
content: I found one of the original NanoVNA's on Amazon w/30% off coupon. Under $32 delivered. Only32 left in stock!

author: cdev
author_rank: Super Contributor
timestamp: January 01, 2021, 04:22:19 pm
content: This is a video that shows how the dynamic range of the SAA2 (N in his case) is much better than the original nanovna but still not up to the task of precisely adjusting a diplexer with a100 db notch.(Note the missing part of the curve indeed needs to be "guesstimated" as its down in the noise floor. But its possible to do pretty well, just not 110 db well. Given some distant signals there, a good receiver can show where the null would be.)You know, the cal kit is up to you. You can buy a better set of calibration loads. The ones I bought are probably better than the ones I've been able to make myself, but that's not saying much.Quote from: virtualparticles on January 01, 2021, 04:08:14 am

author: casterle
author_rank: Regular Contributor
timestamp: January 01, 2021, 07:19:38 pm
content: Now that I'm dipping my toe in the water with the NanoVNA, what about cables? I've got a number of those thin cables with SMA connectors (what are they called?), and a number of SMA-to-something-else adaptors. Oh, and one of those funky test boards with a Smith chart on the back.Thing is, with the exception of one or two cables supplied by big-name clients over the decades (which I know were top-of-the-line), how good are these things? I have to assume an expensive big-name cable is better than what must be the sub-dollar cables supplied with the cheap boards, but assumptions being what they are, is this correct?Can I trust cheap cables? Is there some way to identify bad ones? I don't want to be mislead by a cheap part while I'm getting started...My readings have led me to believe that the quality of the calibrators that come with the unit is critical to accuracy. Do I need to buy another set of calibrators (which would, I hope, be useful with the V2+4 whenever it becomes available again)? If so, recommendations are welcome.

author: cdev
author_rank: Super Contributor
timestamp: January 01, 2021, 08:52:05 pm
content: You got a VNA. How do your existing cables check out?

author: Bud
author_rank: Super Contributor
timestamp: January 01, 2021, 10:00:51 pm
content: Quote from: casterle on January 01, 2021, 07:19:38 pmhttps://community.keysight.com/thread/2321

author: casterle
author_rank: Regular Contributor
timestamp: January 02, 2021, 10:33:33 pm
content: Quote from: cdev on January 01, 2021, 08:52:05 pmIt will be a few days before I receive it. Never having played with RF stuff other than 'doing as I'm told' to hook things up while testing my software, I'm not sure how to check my existing cables. It seems to me one of the things I ordered from AliExpress was an 3GHz RF generator, perhaps with a noise source. Would that be helpful?Sorry if this is an stupid question...I haven't thought about this subject much since I was a kid in rural Ohio, where we had CB's because some of our friends still had party telephone lines which we couldn't tie up with chit-chat (party line: several houses sharing same copper pair; privacy neither included nor optional).

author: casterle
author_rank: Regular Contributor
timestamp: January 02, 2021, 10:41:28 pm
content: Quote from: Bud on January 01, 2021, 10:00:51 pmThanks for the link. I have no idea what "put data->mem, then Data-Mem (NOT Data/mem)" means, but I think I get the gist of it. Will I be able to do the equivalent of "data->mem" with a NanoVNA?

author: Bud
author_rank: Super Contributor
timestamp: January 02, 2021, 11:10:46 pm
content: It was a reference to the function on the older HP VNAs to save a trace to memory so you can then visually observe the difference between the reference trace and the current trace.I do not know if that Fisher-Price toymininano vna has such feature.

author: casterle
author_rank: Regular Contributor
timestamp: January 02, 2021, 11:23:51 pm
content: Quote from: Bud on January 02, 2021, 11:10:46 pmAs I understand it, I can dump data to my PC from the NanoVNA so comparisons shouldn't be a problem.

author: cdev
author_rank: Super Contributor
timestamp: January 04, 2021, 01:02:43 am
content: The nano VNA does support some basic math functions.nanoVNA saver also has some more.If there is something you need to do thats not built in , do you know how to use any spreadsheet like Excel, open office Calc, etc? If you do you likely can do this using the math functions and averaging. That's basically what all these instruments do. The math can be done by the onboard microprocessor or offloaded so you can do it on your PC.

author: Electro Fan
author_rank: Super Contributor
timestamp: April 01, 2021, 08:08:41 pm
content: For a NanoVNA with a firmware screen says SAA-2N (it's a NanoVNA SAA-2N V2.2 Vector Network Analyzer 50KHz-3GHz, 4" screen, metal case, N connectors) and the currently installed firmware has an installed date of November 17, 2020, any ideas on if or where any newer/recommended firmware might reside? ThanksEdit: some people recommend "V2.74" from blackmagic which appears to be about a month older than what is installed, and then there is also "2.8" V2 with metal case which has a higher rev number for whatever that is worth. Of these three choices, (whatever was installed in Nov 2020, 2.74 blackmagic, and "2.8") are any likely to be a clear winner? Also, any idea if this is a deadend product or if there is likely to be path to firmware upgrades?So far this looks to be homebase for the product:https://nanorfe.com/nanovna-versions.htmlOr maybe there are other resources that would show a better path to the future?(Out of all the products that get discussed around here, the "NanoVNA" product category has to be a contender for most confusing.... just sayin').

author: cdev
author_rank: Super Contributor
timestamp: April 01, 2021, 10:09:23 pm
content: Not only do you get to check your existing cables, it will also give you the info to be able to figure out where they are broken to a fraction of a cm. .Quote from: casterle on January 02, 2021, 10:33:33 pmA nanovna has its own RF generator built in (althoughy unfortunately its only usable with the NanoVNA2 not as a CW source. But it will generate any frequency you want up to 4.4 GHz, well enough to test cables or filters to your hearts content. ..

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: April 02, 2021, 03:26:58 pm
content: I bought one and don't know why.

author: cdev
author_rank: Super Contributor
timestamp: April 03, 2021, 02:45:41 am
content: It's a fun toy and good for testing cables better than anything else.Quote from: joseph nicholas on April 02, 2021, 03:26:58 pm

author: joeqsmith
author_rank: Super Contributor
timestamp: April 03, 2021, 02:07:36 pm
content: Quote from: joseph nicholas on April 02, 2021, 03:26:58 pmIf you are interested in experimenting with RF circuits, at $50 you can get a lot of bang for the buck with the NanoVNA and collect some pretty decent data up to 300MHz. If you want to experiment at higher frequencies, at $130 the V2+4 is an impressive bit of hardware. If you want to do narrow band experiments, stick with the old hardware.Even if you bought yours based on hype, keeping up with the Joneses, or have zero interest in RF and just like loading new firmware into your devices, it's not much of a financial loss.Quote from: blueskull on April 03, 2021, 02:54:21 am$50 is one thing. You're on a whole new level. The old saying: "A Fool And His Money Are Soon Parted" comes to mind.

author: Bud
author_rank: Super Contributor
timestamp: April 03, 2021, 02:34:11 pm
content: Quote from: blueskull on April 03, 2021, 02:54:21 amYou need a girlfriendShe will fix that sort of spendings quick.

author: cdev
author_rank: Super Contributor
timestamp: April 03, 2021, 09:56:45 pm
content: If the real estate wars in Shenzhen are anything like the ones here, dropping out of it is a good decision. Its a bubble and when it breaks it will be ugly.I am lucky that I pursued a path much like yours. The area I live is kind of a diamond in the rough. often maligned, its actually loaded with interesting opportunities and a world class center of high tech. Culturally it has a lot going for it. But its eclipsed by the nearby metropolis.Quote from: blueskull on April 03, 2021, 04:06:31 pmIts even worse than that in San Francisco. The place I left behind.QuoteHow does one couple the VNA to the typical traces on a PCB in order to use the VNA for TDR stuff? I have some ultra-tiny mini-circuits 1:1 baluns, I think they will do okay if I use copper tape to connect to the PCB.

author: cdev
author_rank: Super Contributor
timestamp: April 04, 2021, 04:05:58 pm
content: thank you.Either copper tape or mini grabbers is probably where I will end up.Quote from: blueskull on April 04, 2021, 03:26:49 am