NANO VNA-F V2 calibration set - Page 1
Forum section: electronics / rf-microwave

author: AI6MK
author_rank: Newbie
timestamp: January 31, 2022, 11:38:35 pm
content: Hi,Just purchased the NANOVNA-F V2 made by sysjoint.com. It feels like a really nicely made piece of gear. So I tried it out by measuring SWR on antennas, coax and a few terminators, after calibrating, of course.I was just about to throw away my coax and 50ohm terminators when I thought I'd measure the resistance of the "LOAD" in the calibration set included in the kit. I was expecting 50ohms but to my surprise it measures 87.3ohms (Fluke 179).So instead of using the "50ohm" calibration terminator provided, I instead used my 50ohm terminators and after calibration the coax (MPD) measured OK (SWR=1.0, flat from 1.8-30MHz).Any insight would be much appreciated.Regards,BRIAN (AI6MK)

author: rob77
author_rank: Super Contributor
timestamp: January 31, 2022, 11:44:40 pm
content: well, the nanovna from china is a piece of crap... i bought it.. my short form the calibrator set left it's pin inside the sma connector on the device.. had to buy a new short and replace the sma connector on the device.. but anyways.. i can't decide what's more glitchy the firmware or hardware... it's better than nothing i guess, but wouldn't buy it the second time.

author: AI6MK
author_rank: Newbie
timestamp: January 31, 2022, 11:56:04 pm
content: Rob,Thanks for your reply. Well I'm a bit speechless. Having a decent 50ohm terminator is fundamental to the accuracy, through calibration, of any VNA and it was only luck that I measured it. I guess you get what you pay for, but I'm still shocked. Time to buy a decent 50ohm SMA terminator.BTW, the only other issue I've found to date is that the display is dim and is very difficult to read in daylight, even after setting to 100%.Regards,BRIAN (AI6MK)

author: cdev
author_rank: Super Contributor
timestamp: February 01, 2022, 01:44:20 am
content: The nanovna2 that I got on tindie from the nanovna2's creators comes with a SOLT calibration set and the short piece is made out of a single piece of metal so what you describe would be impossible. I paid $65 for my nanovna2 and it was a fabulous deal. The two short pieces of coax it came with are decent quality. Overall its really one of the best deals Ive ever gotten in electronics. I'd be hard put to match it for many times its price. A decent VNA often costs as much as a small sports car where I live. And the nanovna2 is definitely decent.Not crap at all.You must have bought one of the clones of which there are many, some of dubious quality.Contactyour vendor,and offer to send them the broken calibrator as proof.You should take close up photos to show what you mean.Quote from: rob77 on January 31, 2022, 11:44:40 pm

author: rfclown
author_rank: Frequent Contributor
timestamp: February 01, 2022, 02:25:11 pm
content: Part of the problem with these VNAs is you aren't sure what you will be getting. I bought from a company that I had dealt with before assuming that with them I wouldn't be getting a clone... bad assumption. The good thing is that my cal kit is actually good. I have HP VNAs so I can measure what's what. My 50 ohm termination is good. My short IS NOT a single piece of metal. You really don't want that because then the center pin turns, which damages the female socket you are mating it with. I don't use the open. You will get a better calibration if you don't. The two short SMA cables that came with mine are actually very good. Port 2 of my unit has a lousy input return loss, so I put a attenuator on that port and sacrifice some dynamic range to get a decent measurement.

author: DH7DN
author_rank: Regular Contributor
timestamp: February 02, 2022, 12:11:12 am
content: I have a NanoVNA V2 Plus4. I started replacing the included calibration standards with a decent quality ones (Radiall, Huber&Suhner, Spinner, R&S) without going down the VNA metrology rabbit hole. Joeqsmith has very educational YouTube videos on NanoVNA and calibration standards where he explains the necessities of good standards in order to make comparable and meaningful measurements.From my experience...- Paying 10 bucks for a (2nd hand market) Huber&Suhner 50 Ohm SMA terminator doesn't hurt much and it has some tighter specs like 50 Ohm +/- 1% over a wide frequency range- I measured the resistance of an unbranded 50 Ohm BNC terminator which was within 50 Ohm +/- 2% spec. Unfortunately, it was equipped with a NTC resistor so temperature changes (+/- 5K) affected the resistance significantly. A comparison to a Huber&Suhner 50 Ohm BNC showed a stable resistance over a temperature range of approx. +/- 5 K- One should stick to one cable/connector "ecosystem" if possible. Mating cheap connectors with quality ones may result in damage and performance deterioration of the quality equipment- You can protect the NanoVNA port connectors by using short pieces of SMA cables between DUT and NanoVNA. Performing calibrations puts some stresses on the connectors so it's better to sacrifice a replaceable cable than risking port wear-out (although they can be replaced...)- NanoVNA V2 Plus4 works fine for me. I was able to perform simple measurements such as SWR/Transmission/Reflection/Impedance without difficulties. It's a very useful addition to the lab

author: rob77
author_rank: Super Contributor
timestamp: February 03, 2022, 09:33:39 am
content: Quote from: cdev on February 01, 2022, 01:44:20 amnot worth the time & effort to deal with the seller in china , and yes it's definitely a clone. for me it was way cheaper to buy the short and the new sma connector. btw.. the calibrator short was also a one piece but the pin broke off.

author: virtualparticles
author_rank: Regular Contributor
timestamp: April 25, 2022, 03:58:37 pm
content: Quote from: DH7DN on February 02, 2022, 12:11:12 amThis is highly advisable. When I checked the 50 ohm load calibration piece, I found it had about 18 dB Return Loss at the highest frequency as measured on arealVNA. That means +/- 3.3 dB reflection accuracy at 8 dB and of course no accuracy at all for 18 dB or more. The Open and Short are OK (if they hold together) although the delay is unaccounted for in the calibration leading to phase errors. All in all, the nano is a good value for the price and the substitution of a decent calibration load is the first step to making it better.

author: cdev
author_rank: Super Contributor
timestamp: April 29, 2022, 12:06:54 am
content: Its very easy to make your own and 1% accuracy is not difficult to attain over the enntire range.

author: cdev
author_rank: Super Contributor
timestamp: May 01, 2022, 02:18:13 pm
content: 87.3 ohms as the load? Please tell us more and maybe uoload a photo of this item. I have some 90 ohm coax that I suppose could connect to it. Maybe its an old old Ethernet terminator? (just speculating) My old cables were old ethernet cables from NASA surplus.....junk..In retrospect I should have kept more of them, they are very useful. But 87 ohms is a non-typical load, IMHO. As long as you calibrate your VNA to see a 50 (or 75) ohm resistive load as load to be calibrated to you should be okay. As far as I can think of...There must be some reason they did that..Quote from: AI6MK on January 31, 2022, 11:38:35 pm

author: virtualparticles
author_rank: Regular Contributor
timestamp: July 27, 2022, 01:11:37 pm
content: Quote from: cdev on May 01, 2022, 02:18:13 pmThe calibration kit supplied with most Nano VNAs is absolutely terrible. Your load was probably defective. The one I got was not what I would consider a load standard, it was more of a cheap terminator. I measured it with a real VNA and it had return loss of 15 dB at the highest Nano frequency. This would mean +/- 3 dB accuracy at -5 dB return loss measurement and horrible accuracy at -10 dB.Best,Brian

author: joeqsmith
author_rank: Super Contributor
timestamp: July 27, 2022, 01:57:44 pm
content: Quote from: virtualparticles on July 27, 2022, 01:11:37 pmAt 300MHz you may be better off making one. On the low cost side the best I was able to do was to buy a bunch of Mini-Circuits ANNE-50+ terminators and sort them. I think I paid $10/ea and bought 8. One was pretty good. The second best of the group was used for the Nano.

author: jmw
author_rank: Frequent Contributor
timestamp: July 28, 2022, 02:55:30 pm
content: Here's a writeup of doing EM simulations, then constructing my own standards. The results are definitely acceptable for working at NanoVNA frequencies.https://jmw.name/projects/vna-standards/

author: Raindog
author_rank: Contributor
timestamp: October 18, 2022, 02:33:39 am
content: I purchased one of these about two months ago. I don't expect to have the same accuracy as a HP VNA but it has worked good enough for me. I haven't had any issues with the supplied short, open or the load. However I do have some quality loads and shorts if need be. I swept a HF low pass filter and was able to duplicate the results I got using a HP 8644A signal generator and a HP 70k series spectrum analyzer.

author: LM21
author_rank: Regular Contributor
timestamp: October 20, 2022, 10:18:49 pm
content: There are atleast 3 versions of NanoVNA. This is a good starting pointhttps://nanorfe.com/nanovna-v2.htmlhttps://nanorfe.com/nanovna-v2.htmlThey differ by their frequency range.

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: October 21, 2022, 06:26:08 am
content: Also if you buy NanoVNA from an official supplier you will get a much better experience (both with the VNA and with the calibration kit) than if you buy it from some random nobody flogging counterfeits.I have one, bought from an official supplier. 50 ohms is 50 ohms and the VNA does a brilliant job for what it is.

author: LM21
author_rank: Regular Contributor
timestamp: October 31, 2022, 03:15:21 pm
content: Quote from: Geoff-AU on October 21, 2022, 06:26:08 amI bought NanoVNA V2 Plus4 from Tindie, and I'm happy with it. Large battery helps stand alone usage. Only problem is that I have three different NANOVNAs, from first to this V2 plus. I have several versions of PC software, I have no idea which works with what VNA, I have to try each every time I'm going to use PC software. Besides most work with Win10But I definitely recommed bying from official store.If you want greater accuracy, buy VNA6000-B or VNA6000-A.Better calibration set can be bought from Ebay, and more accurate fromhttps://www.sdr-kits.net. I would not buyhttps://www.sdr-kits.netVNA, but calibration kit looks good. I'll probably buy one of those some day. You can spend much more money to calibration kits, if you want