Setting up the NanoVNA for checking baluns and insertion losses

Don't run away! Sorry for the 15 second delay before the video starts.
This video will show you how to set up a NanoVNA for testing baluns, chokes, filters, antenna switches and more. You can even check a home brew plate choke for an HF amplifier for attenuation as well as self resonance.
People have asked me about the attenuator. Once you do the calibration, the 10 db attenuator becomes transparent. You do not add or subtract that value to your readings.
Here is a link to part two of this video. It shows how to check antenna switches.
• Setting up the NanoVNA...
Barry
Update: The 20 DB benchmark was given in someone else's youtube video. If you want to equate DB attenuation to ohms needed on a core, here is what you are looking for to set your own benchmark.
10,000 ohms = 40 DB
5,000 ohms = 33.9 DB
3162 ohms = 30 DB
1778 ohms = 25 DB
1000 ohms = 20 DB

[@johnwest7993]

A very clear, practical, straightforward instructional video of exactly what to do, and why.

[@clems6989]

Another great video. I still think this channel is horribly underrated...

[@simongreen3726]

Thanks. Just followed your methodology to measure the resonant frequency of an airwound coax choke for 6m. Worked a treat!

[@Mojomo777]

Thank you very much, I still keep learning how to do this correctly and very helpful when I need to refresh my memory.

[@K6TJO]

Barry this is exactly what I was trying to learn. THANK YOU!!! 73 de K6TJO!

[@radiofhi]

A great instructional video on why and how to calibrate a Nano VNA. Brilliant and concise. Thanks! Bob K4FHI

[@jeffwillams2773]

I found the 43 and 31 are very similar although I wind mine differently. Super video.

[@pmsecretary52]

Another good video thanks Barry

[@laurynaslauris9677]

very good video for setting up vna

[@cschmittie3284]

Wow! Very informative! Packed with useful stuff. Definitely going to work on this. W0AP

[@HammerToneAmps]

Thank You Barry. Excellent explanation this procedure. I'm curious about the purpose of the 10db attenuator?

[@1babydean]

Enjoyed it very much. Thanks

[@boxingday11]

Thanks Barry👍🇬🇧

[@diogenio]

The BEST video of its type on KZbin. Great job, Barry. 73, W1LJ - since 1974

[@eugengrzondziel1706]

I saw so many videos about measuring of commom mode chokes but this is the first, it shows the instrumentation needed for and the fully measuring procedure. Thank You very much for your work! Well done. 73 de DM5GE P. S. could You explain the function of 10 dB attenuator your test fixture?

[@shanerorko8076]

What is the attenuator for?

[@AB1Vampire]

"this isn't Hollywood" My kinda Ham

[@joeminor6314]

Thank-Goodness

[@debohannan4315]

Fantastic video been wondering how to do that , I have been building coaxial sleeve chokes for 2 meters , they work but don't know how well so any chance you can do a video on that ? Thanks keep up the good work.

[@washingtonstatepicker3460]

Thank you for the video! I am trying to learn to make baluns now, so ugly baluns don't work? What about Ferrite beads? I ordered some clamp on ferrite beads from Palomar for my homemade GMRS/MURS and 2m/70cm antennas. How would I test those?

[@randyslaten299]

Very informative presentation! I may be wrong, but it looks like you connected a jumper between input and output of the 1:1 isolator (@ 19:14) instead of connecting it to the nanoVNA. If that was the case then bad readings were caused by no readings taking place on the 1:1 isolator. Overall, great explaination of testing methods for these devices.

[@de_w8tam]

Question, what is the purpose of the 10db pad on S21? I realize you've calibrated it out, but I'm not sure of the point of it. Is it basically to present a 50ohm load to S21? 73 de w8tam

[@02vLxcZF]

I have the same question and tempted to suggest the same answer. Have you worked out a different response since then?

[@de_w8tam]

@@02vLxcZF nope.

[@02vLxcZF]

@@de_w8tam Ok thanks. Best guess is to simulate a 50 ohm antenna going into the balun, and the only piece of hardware available if you want to avoid a messy set-up with resistors soldered onto pieces of wire, is the attenuator...agree?

[@jimf1196]

@@02vLxcZF Don't you hate when the author doesn't answer any questions? He is only measuring the insertion loss of an inductor here. I don't know why either except if you were testing a real Balun with a ratio that gives you a gain on the output it might overdrive the input to the VNA and damage it. I'm just guessing too.

[@jefferylegere]

could you do another where you show the cable setup better? i am lost as to what connects to what.

[@izzzzzz6]

Hi. Can anyone help me with using a VNA with open wire and balanced antenna? I am wondering if i can measure the antenna impedance at the feedpoint and then build ladder line to match that impedance. Then can i use a VNA at the shack end to see what the total impedance is at height? The problem seems to be how to connect open wire to a VNA and will that be accurate once the spacing from the ladder line is brought tight in to the coax connector on the VNA? The object is to A. Match / build the ladder line impedance to match the antenna impedance and then to measure total impedance at the shack so as to know the best ratio of Balun to use in the tuner. Thanks.

[@izzzzzz6]

I've got some ring magnets that i found in a fire, they came from speakers but the magnets lost their magnetivity from the fire. Does anyone know if i can use these ring magnets as either a transformer core or as a ferrite bead to choke common mode or parasitic noises? I have lots of ring magnets on broken speakers, some quite large. I'm wondering if i can give them a 2nd life.

[@mholzer54]

KU3X de N6UNX - Nice presentation... I have what I believe to be a proper Nano VNA but a less expensive one that has a MAX of 101 samples. I built a choke using a 140-43 toroid and RG-174. It behaves well hooked up, and my Nano VNA is showing -35 Db at around 6.5 MHz with a nice slow curve up as it heads upward. At 10 Meters it is around -13 Db and at 20 Meters around -26 Db. Not bad, I think. And you? By the way, I can hear the difference, about 2 S-Units down on 20 Meters. And at 100 Watts CW, the wires don't warm up. It is in line with a home-brew End Fed Half Wave. Great pairing of Toroids! 73, Marc - N6UNX

[@Capt_Duffy]

Sir, first of all, it was simply an Outstanding video, cleared lots of confusions..i have a question, i ve just made a balun, i ve tried everything changed the winding many times but simply cant pass the 27db of attenuation using 240-31 toroid, what could i change ?

[@barrygkx]

If you wind 14 turns of coax around an FT 240-31 core, at 160 meters you should read around 33 db. It increases from that point on and goes down to 27.6 db on 10 meters. On 30 meters you should get around 35.2 db. Even if you only have 10 turns of coax around this core, on 80 meters you should see around 30 db and on 10 meters you should see around 29 db. Barry

[@lu1fdu]

How many db would be fine using 1500w?

[@victorb22622]

Theoretically and practically good ,but i cannot saw the full connection of left side of nano vana ,so it was not cleared what did you connected with nano vana as it does not seen while wire

[@jonathanwatmough9871]

Excellent thank you

[@w4mpx]

Thanks!

[@gravestonemyth]

My NanoVNA H4 does not have the sampling menu 😞

[@g0fvt]

FWIW the NanoVNAs are beautiful to use with the right software on a PC, did some sweeps of my common mode choke which is wound with RG142, attenuation with a stack of 4 FT240-43 is about 37dB at 1MHz, peaks at 42dB at 1.3MHz but gets worse and worse going towards 10m. I have a further pair of ferrites to improve 10m. Need to pull some turns of the big stack, Capacitance between turns might be skewing my results.....

[@jefferylegere]

what is the right software?

[@g0fvt]

@@jefferylegere I have used NanoVNA saver. Email me and I can send screengrabs from it.

[@oldbassist60]

With a stack of four, you're looking at wire length, winding wrapping methods, distributed capacitance. With that much inductance, you'll see degradation the higher you go. One - maybe two cores and the correct wire type, size and insulation will give you results. KZbin TRX Lab. he does an excellent job at explaining your exact problem. Use #16 PTFE stranded for 1:1 chokes & 1:4 baluns and #14 solid for 1:9 enameled with tape wrapped over the core.

[@oldbassist60]

@@jefferylegere SimSmith has been recommended to me. I just received my Nano VNA. Google VNA Software. Much of it is free.

[@g0fvt]

@@oldbassist60 since then I have built them differently. So far the best for broadband common mode impedance has been wound with 2 twisted pairs from CAT6 cable, just 2 cores. CAT6 has low loss at HF and each twisted pair has a characteristic impedance of about 100ohms.

[@GreenGuyDIY]

Don't know what I am doing wrong. Even if I simply use a single thru cable supplied with the Nano and do the steps 1) end of cable attached to S11 with open, 2) short, 3) load, 4) end of cable open and load on S21, 5) cable connected to S11 and S21 (thru); the sweep does not go to 0 but stays at the bottom of the screen. As I move the marker it stays around -1.9dB. Would this be because I am not using the 10dB pad?

[@GreenGuyDIY]

Got it. somehow I paused the sweep. Thanks for the lead on sma to terminal.

[@rfburns3472]

Does anyone know why the 10 db attenuator is necessary?

[@markashley5074]

It's absolutely not necessary.

[@NikoSan713]

Hello, I don't understand why you need a 10 db attenuator? and Why 10 and not more or less? 73' F4JPC Nicolas

[@bushbuster9703]

50 ohms

[@antoniomartina6960]

Grazie 73s a tutti da ON3RA

[@Nobody-ld7mk]

Don't know how they do it... 6.5:1 exchange rate.

[@hankhamner3671]

You should have calibrated to the end of the test fixture. Otherwise your results are incorrect. Also, why did you find an attenuator necessary. Finally, 20dB is not the best measure. You need to have at least 2k ohms of resistance and this needs to exceed reactance.

[@BarefootBeekeeper]

Are we allowed to describe connectors as male and female any more? 😉

[@n4lq]

i guess I don't understand.... Why are you calling a single piece of wire....a balun? It's just an inductor. Although the principle is the same an actual balun won't read that high of an impedance causing the unaware to think he did something wrong.

[@cf6156]

Very nice video. Congratulations, but you are not measuring a balun ! You are mesuring a device that look like a balun .... Balun mean measuring first amplitude and phase imbalance or cmrr . Vswr and insertion loss are important but not esencial . You can have in your hand a device that has a nice vswr and be insertion loss , but not working well as a balun. Regards. Good luck

[@rudiwiedemann8173]

DUDE! You don’t have a BalUn, UnUn OR a common-mode current choke there. You’ve got a simple toroid core inductor! I don’t know what the HECK you’re trying to demonstrate.

[@barrykery1175]

The test is the same principal. Do the same follow the same test procedure and you will get the same attenuation results.

[@Echo_Hotel]

You shouldn’t be holding any of the wires while calibrating or testing…

[@barrygkx]

Think of what you are saying? Coax is like a water pipe, all of the water is inside of the pipe just like all of the RF is inside of the coax. There is no common mode in this setup. So if all of the RF is inside of the coax and what goes on outside of the coax does not get into the coax, "How does touching the coax on the outside effect what goes on inside of the coax? " Nothing different than touching the outside of a water pipe, "does it effect the water flow?" The answer to both is, "NO !" Barry, KU3X

[@Echo_Hotel]

@@barrygkx wow marking you off. The water analogy was meant for secondary school. How about you ponder this what would be the condensation in this analogy?

[@bruceblosser384]

How about a rehearsal of what you are going to present... commonly not used - but universally required for an intelligible presentation - I simply can not sit through 20 minutes of himming and haawing, while I wait for the interesting parts! :)