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- Опубликовано: 27 авг 2024
- This video presents the basic definition of a vector network analyzer (VNA), a practical view of how some of the measurements are performed, and an introduction to some of the common measurements that are made. A few examples VNAs are shown. Knowledge of transmission lines, reflections, VSWR, etc. is helpful, but not required for this video. Here are several additional video links that may be helpful:
Directional Coupler videos:
• #158: Directional Coup...
• #196: How a Directiona...
Transmission lines, reflections, and standing wave videos:
• #143: Transmission Lin...
• #208: Visualizing RF S...
Smith Chart videos:
• #297: Basics of the Sm...
• #275: Smith Chart: Z, ...
Notes from this video:
www.qsl.net/w2a...
Your videos are excellent. I have a PhD in Physics and I'm a radioamateur. You should be awarded some kind of prize, especially for not turning everything to monetization and for the extreme clarity of your notes and explanations. Also, watching your videos makes one want to experiment, and I think this is the most important result you can get.
My wife of 33 years said if I buy a new Tek TTR506A VNA she is going to leave me. Boy, I’m going to miss her!
Collateral damage 🙃
Haha :)))))
You'll have to deal with lots of swr.
😂😂
@@poetryinmotionsightsandsou9094 Actually, I think you mean lots of "signal loss" LOL... giggle
My wife is trying to find a w2aew rehab Centre for me. Your videos are addictive in brilliance and content. Excellently done..
😂
Citing this video in the lab manual I'm making. This channel is a gem.
Thank you - I hope your students find it useful.
You break things down so well. This is the first time I've had S22 fully explained. Why can't people just say "reflection off of the output port?"
I bought a NanoVNA and it is amazing. It has allowed me to accurately measure inductors that i have wound ( many were quite off supposeded calculated value) as well as tune antennas easily. It has been worth every penny for sure.
If you had a good osciloscope & frequency generator, you could work out your inductance with the use of a tank circuit and a known good capacitor/s... maybe cheaper than the nano.....especially if you already have this gear I mentioned.
Really, and the NanoVNA V2 extended the measuring range, it makes 2.4GHz antenna tunning easily.
@@ziyuewu3715 oh wow i may need to get a new version!
@@michaelhawthorne8696 i used to use that technique but my osxilloscope is an analog scope and it doesnt get bright enough to see the traces to see a tank circuit ring. Plus lots of calculator involved. Also it still requires the capacitor to be accurate with that method. The nanovna doesnt need the capacitor..and it already reads out in microhenries so its super easy to use.
Also i found the inductors actually change in value over frequency ranges (what measures as 10microhenries at 5mhz may only be 6 microhenries at 10mhz) this was not expected. Thoery always states the inductance value is only based on turns, etc. But that shows the ring technique also will not be truly accurate unless you use a tank close to the frequency your circuit is going to be. If you are building a chebechev filter you have to be accurate or it wont work properly at all
Sadly the standard 2.8 inch NanoVNA screen is too small for my eyes to easily read the text :( But I have heard a rumor that a 4 inch screen S-A-A-V2 version may be in the pipeline. :)
Best video that I have ever seen about the RF measurements. Thank you so much for your informative contents !!!
I have no words about how seldom and useful videos like that about VNA! Thank you very much!!!
Thank you so much for demystifying VNAs for me. I never knew what they really did as Google's explanation wasn't really helpful, as you pointed out. A great video as always. I know how much effort there is in turning out videos, the work you do is greatly appreciated!
Watching your videos always tells me how much I have yet to learn. I always glean usable info even if I don't grasp all of the subject. Thank you for sharing your knowledge.
Oh hell yeah! W2AEW talking about VNAs.
Thank you for sharing your knowledge with us. I am pretty new to radio only being at it for about 6 months. I just got one of these and your video and notes are an amazing resource.
I watched this a while back and benefited from it's teaching, so just wanted to say thank-you!
Subscribed. I salute how wonderfully White this engineer and teacher is.
Another great educational video on VNA's and how technology and embedded circuits have now put very accurate test and measurement equipment affordably put the into the hands of almost anyone.
Excellent presentation, I was actually searching for vectorscopes and this came up, none the less this was time well spent.
This is the only channel I watch at half speed to ensure I don't miss anything!
Your videos are extremely good Alan and I look forward to every one. I'm glad you are providing some introductory content on VNA's - I'm just starting to venture more into them...Perfect timing!
Great Summary! I spent hours reading Tektronics manuals vs a succinct 17 minutes of your video to get the same information. Appreciate this :D
Thanks for the video, Alan - excellent as always.
I bought a Nano VNA because I was having issues with the range of the anti-collision device in my sailplane. It allowed me to design my own antenna which has vastly improved the coverage, and given me greater time to respond to warnings. Without it, I would not have had a clue how bad the various proprietary antennae were at the frequency used, 868.3 MHz. It allowed me to get pretty close to the centre of the Smith Chart even without a matching network and it shows around -30dB reflection loss and an VSWR of less than 1.1. Can't think of anything else to use it for yet but I am a 'newbie' to the world of electronics and particularly RF.
@H Higgins Maybe at the end of the season I will do some more work on it but we have only just been allowed to start flying in the UK because of all this Covid nonsense. I just need to concentrate on the flying for now. The Nano seems to give A+jB info as well so I can maybe get things better. The matching seems incredibly sensitive to co-ax length! Furthest ground contact so far is about 2dB @ 94km and this from about 10mW output so I am pretty pleased with it.
Thank you. For making these videos for us! I still remember the first time I saw one and I was so happy to have some one to look to for help. You are a great friend to me.
well done sir, well done. I spent all of last year using signal generators, spectrum analyzers and Oscilloscopes running acceptance test procedures on electronic countermeasure systems. I did not have to use network analyzers but did look over the shoulder at the next test bench that was using one to troubleshoot some issues. Your video now helps me understand network analyzers enough to do my next assignment.
Know you're busy with work so thanks for taking the time to begin this VNA discussion. Stay safe! 73 - Dino KLØS
Very well done, as you typically do. It is so refreshing to see a fellow ham that is truly an RF pro - getting scarce these days. I notice that in Raleigh, NC there exists a "Smith chart amateur radio society" - a club whose members must be able to demonstrate competence with the chart! My kind of club. 73 de W4NEQ.
Thank you so much, sir ... very informative and simple to understand
Everyone of your videos is clear, concise, and enjoyable. Automatic like. I love my RSA507A. Until I save up for a TTR503A, an external coupler is getting me by. My calibration set is built with help from your previous videos. They compare well enough to commercial sets. My use is greater than hobby but less than a research lab. Thanks for the excellent videos!
I wonder if you got the tracking generator and reflection measurement options. That turns this fine realtime spectrum and vector signal analyzer into a 2-port, 1-path scalar network analyzer.
w2aew Hi Alan, I do have the tracking gen. I don’t have the return loss option. I have considered it though, and still may get that. I use an external directional coupler with it, but don’t get the metrics provided by the option. I want to be able to do phase type measurements and use a smith chart. If the RSA can do that in the future, That would be awesome. At the moment the Rig Expert AA-1400 helps me with antennas. For now it’s filling up the penny jar for a TTR.
@@stevefoudray487 You can enable a 30 day trial license for the Reflection measurements, so you can try before you buy. Currently does not do phase (thus, no Smith charts), just scalar return loss, VSWR, distance to fault and cable loss.
Very informative and timely. I just ordered a Nano VNA. Now waiting for more videos to show me how to use it!
Finally a series about VNAs ! Maybe I will finally understand what is lost in the "Return Loss"
Alan, I love your Videos. I have many RF courses and I always love to share your videos with my classmates and they are always thankful. Our stuff is so dry, mathematical and without examples but your videos help us so much. Please stay healthy and save!
I love your explanation i didnt know how to use ut and when to, but explaining how it works now also allows me to fully understand and appreciate this awesome piece of machinery
Wow you made this video just in time. I was about to buy a NanoVNA to start getting into RF and this is exactly what I needed. Love your videos, thank you so much!
This reminds me of being an undergraduate and trying to use a Time Domain Reflectometer to diagnose a local area network problem.
MIT Chaos Net ran over 1/2" UHF cable (sorry. I don't know any details, though I might recall correctly that it was 50 ohm). The TDR would apply an impulse on the cable and then plot the voltage over time. Any place where there was a bump in the plot indicated a problem on the line and you could calculate how far from your test point the problem was based on the time lag of the reflection.
After one of two times doing this we eventually learned that the problem was always in the Building 38 basement phone closet. This network cable was stuff and fragile and had a minimum allowed bending diameter of about four feet. The cable needed to make a large turn there and whenever a workman leaned a ladder against it it would kink the cable. I think we had to fix that once, but I don't recall how.
You're always educating me. I needed an overview of the VNA
I just had a phone interview (2020 ECE grad) about the difference between a SA and a VNA the other day and your videos, along with some credit to the signal path, allowed me to answer him with confidence! Thanks so much for your videos, they're amazing
Good luck with the job!
@@w2aew thanks so much! :)
Thanks Alan. My NanoVNA (a Fathers'Day gift) arrives today, so your video was very timely. TRGHS. 73 Bill N2CQR
Cool - good luck with it Bill. Let me know if you have any questions!
Finally! Asked you for it some time ago (for I can understand your explanations best), and now it is here. Thank you sooo much!! You can't imagine how perfect the timing of this video is for me. Thank you, thank you, thank you!.
Best practical introduction to vna! Great demonstration.
I've not understood need for two-port measurements for most all situations. Our "nano" versions do very well.
Always invaluable info, looking forward to the next part in the VNA discussion...
Cheers,
This little VNA gives me a wealth of information about my antenna. I'd LOVE to see a video on how to interpret the data, and make use of that interpretation to know what I need to change about my antenna to optimise it.
The VNA can help you to measure your antenna's impedance match to the transmission line which helps you to get maximum power transfer (minimum SWR, S11 reflection coefficient). See video #314. But, it can't help you make it a more efficient radiator.
Great overview! Looking forward to the followup video(s) with comparisons. 73s
Thanks for that, looking forward to seeing your video on how to use a VNA! My school has some nice R&S ones but I wasn't too sure on how to use them.
Awesome video. And thanks for giving examples and your opinion on the existing VNAs on the market.
Thanks for the excellent presentation and explaining the basics
I've been waiting for you really dig into this series!! thanks for sharing your knowledge
Thanks so much for a VNA series. Got a bench full of aging Tek and HP equipment, never quite got my head around VNAs, but have been shopping a little; surplus lab VNAs are still awfully expensive in hobby terms. This will be most helpful!
Excellent introduction to how a VNA works! I purchased the NanoVNA last fall and really like all that can be done with this very inexpensive instrument for amateur radio. Thank you Alan!
As always excellent explanation. Even I know what VNA is and also using it frequently is really nice to see some clear explanation of the basics behind.
Scope probe is the coolest way to point during presentation
Wow great info that has been needed for years. Thanks. Keep em coming,
Very good explanation. Clear and understandable. You are good instructor. Thanks..
Great to find your channel. Ironically, I was chatting with a colleague recently about network analyzers and, voilà, this video popped up. Nice presentation.
Thanks God your healthy. Another excellent video.
Very informative video and very well explained. I highly appreciate your work. Thank you!
Thanks for sharing. I can't wait for more content on the NanoVNA.
very nice...cant wait for next videos for how to with VNAs
Excellent tutorials with theory and applications on the bench! I admire your test equipment collection as it is very high grade -- Tektronix and others and notably your very clear layout of contents on graph paper which is indicative of good engineering practices and communication skills in total.
We would all love to have 100K budgets for pro grade gear but it is useless without the knowledge and training to make use of such instrumentation and how lower cost but useful devices that are affordable compare to "pro grade" instruments that are now very available.
Your presentations are "classroom'" grade, instructive and a real service to elevate our desire to expand our knowledge and engineering practices!!!
Many thanks!!
You make it easy to understand, thank you.
As I have said many time, these videos are brilliant. Thank you very, very much.
'Magenta' is the color name I believe you have there. At least that's the name we use in the cockpit to refer to our navigation "magenta" line.
Excellent video presentation on VNA's It's one of those must have tools for RF work and play. I'm really surprised how well the NANO VNA measurements are so closed to the expensive VNA's like the HP 8753 and Agilent FieldFox units. For home use such as Amateur radio it's hard to beat that low cost for this type of RF tool. Thanks again for the video and looking forward to more .
Perfect timing. I'm looking forward to the coming videos 73 NE5U
Another item in the wishlist / cart. Thank you for the in-depth introduction.
Congrats on your mention in this month's QST. Best 73's de WD6FIE
Thank you! I haven't gotten my copy yet!
I'm Considering buying one of these. You helped to bring me up to speed with your explanation! 73's de KC2RDU
Great videos, thank you!
Thank you so much by very instructive video. RF is a fascinating science. I have learned many new things with your video. Although English is difficult to me, I will try attend your others videos.
This was just terrific
Alan thanks for another great video.
I have been used to the old scope and sig gen trick for doing time domain reflectometery. But nice to know a nano vna can do that too!
I teach license courses for novice hams. At this rate I'll soon replace myself with a playlist of your videos.... First rate video, as always!
Hopefully they'll help your students.
@@w2aew They help me! Fake it till you make it :) But seriously, they really do help! The Back to Basics are a seriously usefull. They also prove a point I've been trying to make for a while which is that you can do these courses as distance learning - I'm a firm believer that the future of the hobby lays not in resurecting CW (not that it needs resurecting, plenty new hams are learning it, at least here in Sweden) but rather in teaching and tutoring as many aspiring hams through their exams as we can!
Great video, as always! I'll receive my nanoVNA in a few days, so I'm looking forward to learning how to use it and make measurements.
Ooops! Your written rho at 9:23 is actually a sigma! - rho has a vertical tail. :) Nevertheless a great explanation and demonstration (as usual).
Oops, thanks for the correction.
And rho is acrually the voltage signal wave ratio (VSWR) not the magnitude of reflection coefficient right??
VSWR = (1 + abs(gamma)) /( 1 - abs(gamma)), which is also the ratio of Vmax to Vmin
@@xmun9236 Complex gamma (rho angle phi) = complex (V reflected/V forward), so rho is the reflection coefficient's magnitude (absolute value), and not the same as Vmax/Vmin (= SWR when the line's not matched). Complex (V ref + V fwd) is a solution of the transmission line's wave equation. So V ref and V fwd can be thought of as independent waves that "combine" to create V max and V min along the line.
I have corrected the downloadable notes.
Very informative, as usual. Thanks.
Great video. I would like to know more about the S parameters. Thank you.
Awesome Content
Excellent! Congratulations!
You explain this very clearly!
Thanks for putting efforts in making these videos.
Thanks again, Alan. I learn something new each visit to your channel. Can't wait to see how the Nano VNA stacks up to the Professional VNA. 73, de KB7ZUT
Excellent video. Well done!
Thanks, looking forward to the next videos!
Thanks a lot for your explanation.
As always, it was very good and instructive
Regards
oh my god this looks so amazing but i havent got the time yet to watch. fffffffffffffffffuuu. onto my watch-later list. you're a champ, w2aew.
Thanks! Damn, I like your videos. Always Very well detailed and explained.
Amazing lesson! I cannot wait for the next :D
Nothing better than Alan over hearty breakfast. Hold on need to get ready for this.
ok i'm back.
Your explanations and clarity of presentations for all your videos that I have viewed are superb. Thanks for the excellent work you do. I fully agree with M@marcozbo. Great job.
Your videos are very useful and detailed, keep up the good work!
Great video, informative as always, looking forward to the future VNA vids!!
I got a interview coming up thanks for also covering return loss and reflection coefficient and s parameters
Great! How did your interview go?
@@w2aew I have it on Wednesday with Apple! It’s for their rf team in Cupertino!!
@@Coolgiy67 I hope it goes well (or went well, depending on when you read this).
@@w2aew Wednesday is in 2 days from now but thanks. I’m also using chat gpt and my rf engineering friend to study for this
@@Coolgiy67 Good luck today!!!
Thank you! Very informative. I like to hear your topics.
Great video, thanks
Another interesting cartoon, thanks again :) Zdravím z České republiky
Every time I watch this channel I get an ad for oscilloscopes 🤓
Well done, thank you for this vid.
I love my NanoVNA only cost me $36 ish off wish from someone around New York. (It works so I can't complain.) I have used it to tune up my 40m dipole I use with my SDR and also found that my dual band vertical on my house might work for some parts of the 900Mhz band.
Great video, thank you!
Oh noes, you've switched from real graph paper to fake one!
Glad to see your video popup in my feed, thanks!
Saving a lot of trees (given all of the editing and revising I do before making a video).
What device is it?
From www.remarkable.com
Oookay, you convinced me - I'll put NanoVNA on my to-buy list...
Very nice explained 👍
Thanks. So far so good and I have some catching up to do.
Very informative 👍