nanoVNA - Alligator Clip Leads vs. VNA Test Fixture Kit - Measuring Inductors & Capacitors

[@JimSky]

Seems like the test fixture should be used in the calibration of the VNA.

[@ve6wo]

Yes, but at these low frequencies…

[@acestudioscouk-Ace-G0ACE]

As a beginner in electronics, I found this fascinating and was able to to follow due to your clear and relaxed presentation style. Thank-you.

[@ve6wo]

Glad it was helpful!

[@danboy3399]

Just got my first nanoVNA and came across your video… great information and easy to follow. Thank you.

[@FUNKLABOR_DL1LEP]

4:41 Hi, great job! I saw You turning the SMA connector into the SMA nut, You should always turn the nut and not the adapter. if You turning the Adapter, it is rotating in the connector, this will damage it over Time. 73 de DL1LEP

[@ve6wo]

You are correct. Since this video was made I have started to support the coax with one hand to allow the nut to rotate while preventing the center pin from rotating.

[@intotheblue50]

A lovely clear presentation style, showing your comparison project which is informative and very enjoyable, thank you.

[@rfburns3472]

Very nice demo. I was about to do the same test. One thing I noticed, and it may be minor, is that you held onto the back allegator lead which may have induced some hand capacity in the measurement. Even though it was the black shielded allegator clip it still could have some effect.

[@keyboarderror1]

I soldered a couple of SMA connectors to Dupont pin headers for an easy way to use them with a breadboard. It works pretty well, and you can use the split sides of the board for through connections. If you don't have a dedicated test fixture handy.

[@ve6wo]

Thank you

[@MichaelPechner]

frm what I can tell the only pins connected to out si column 7 rowsc,d,e. B ut you connected the inductor to row A. i assume you modified your board?

[@ernestb.2377]

Great experiments. And of course we would need a test fix for smd as well...

[@IK8XOO--Paolo]

The reason you find difference using the alligator clips cable probably is due his characteristic impedance, bnc connector included. Check starting from there: does it use a 75 ohm bnc version?

[@enriquea.wembagher5537]

Gregg ...Excellent work and demostration !!!! Vy 73

[@davidh1187]

OR 948pf for the capacitor - which the VNA can measure.....

[@JPEE2012]

I would have thought that the calibration for the alligator clip would be more accurate, because you calibrated it to the tip of those. With the test board, you did not calibrate it inline with calibration procedure- it was left out. That board could affect the capacitance and inductance, right?

[@ve6wo]

Yes, however, at the wavelengths we are using to make these measurements this small change in length means very little to the resulting measurement. At higher frequencies, this becomes much more critical.

[@ka2pbo]

That was fantastic! Great explanation the whole way. I agree; for ham radio and electronics experiment stuff, the clip leads are just fine. I have a test fixture but always go to the clip leads .As long as you calibrate each and every time, you're good to go. 73 and Thanks

[@DmitryAvsioukov]

When solving back for L you've actually solved it from calculated frequency, not measured one. No surprise you've got your 14.8uH back :)

[@ve6wo]

Yes, I’m not entirely happy with that part of my video. Looking back at it, I think I could have presented what I was trying to say more clearly.

[@ivolol]

I really don't see the point of your segment at 18:34. You essentially only re-did your same previous calculation backwards, except with a bit of rounding error stemming from initial truncation of the result. I speculate that maybe you got confused, and actually wanted to find the value of what L should be if inserting the measured tank frequency, 1.344Mhz, rather than the calculated, 1.358. Doing that, I got a calculated L of 15.11uH. Otherwise, cool video on using nanovna to inspect component values and resonances. And I solved the above using the exact same calculator :) Funny enough your alligator readings got 2000khz closer to the tank measured frequency.

[@ve6wo]

Now that I haven’t looked at this video in a while I should go back and see if that section you mentioned makes sense.

[@TheSmokinApe]

Well done, I really enjoyed this video 👍

[@ve6wo]

Thank you :-)

[@jwrtiger]

Nice video, thanks!

[@Sethz71]

Big fan, keep it up Gregg!

[@galileo_rs]

You are measuring the fixture and the DUT, calibrate using the fixture connected. When you adjusted the stimulus you forced the VNA to do interpolation, not that important in this case but generally a bad practice.

[@ve6wo]

Yes, but at these low frequencies, I challenge you to do the same test twice, using the correct method and then using the ‘bad practice’ method… and tell me if you see any kind of significant difference. ;-)

[@galileo_rs]

@@ve6wo Generally true but it depends on the DUT. For example try measuring a 10K resistor using a "S21 method" and comparing the results that you get with an ideal model (SimSmith is great for that). For example, place the test jig directly at port 2 VS the usual way of using a coax pigtail. Now, does any of that matter for amateur radio usage, not really but it is good to know how to do it properly and it is a fun experiment.

[@ve6wo]

@@galileo_rs I agree

[@galileo_rs]

@@ve6wo 73 YT3ART

[@geokuf9679]

Excellent, thank you, 73

[@BobMellor1954]

Thanks for this, very interesting, just subscribed 73 Bob

[@ve6wo]

Thanks for the sub!

[@renaat9829]

👍👍👍👍😊😊😊😊