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How To Measure Ferrites using a NanoVNA

Ham Radio DX

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How effective are various ferrites in RFI (noise) suppression? You can use a NanoVNA to find out!

⬇️ Equipment in this video ⬇️
NanoVNA SAA-2N 👉 https://geni.us/YPOGD0
NanoVNA H4 👉 https://geni.us/SqRmO

⬇️ Ferrites ⬇️
FT-240-43 Ring 👉 https://geni.us/qpzIxP
FT-140-43 Ring 👉 https://geni.us/ps6to
Clamps 👉 https://geni.us/DVfAN

I wish I knew this when I started Ham Radio 👉 https://courses.hamradiodx.net/b/LmQGB

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Up next:
Using a NanoVNA to Fix Our Repeater Coverage
How Long Is Your Coax? Testing with NanoVNA

⏱️Chapters⏱️
0:00 A ham's best friend
1:23 Using the NanoVNA
2:52 Calibration and setup
6:19 Testing Clamps
13:56 Testing Rings
17:00 Testing Beads
18:13 Random ferrite cores
19:00 FT140-43 test

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#HamRadio #AmateurRadio #ferrite

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20 Comments

@HamRadioDX Creator 8 months ago Pinned

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@silvermica-u3d 1 year ago

I have been in the electronics field professionally for 39 yrs and this video was really interesting and informative. Thank you!

@larslindgren3846 1 year ago

I really don't understand why most ferrite cores aren't marked with material type, brand and part number.
It makes it easy to get them mixed up.

@JamieStuff 2 years ago (edited)

You are on the right track with the resonance theory about your "3 turn" coil. This is evidenced by the fact that you are showing +6 dB on 2m, so you definitely have some E/I phase games going on. All coils have a self-resonant point, due to the L of the coil, and the (parasitic) C vetween the turns of the coil. I would expect a MUCH different result if you spread the turns around the ferrite.

The Smith chart should explain what's going on. I might dig out my NanoVNA and do some experimenting.

(Edit: I'm an EE, though it's been a few decades since I studied this.)

@williamscott8397 2 years ago

I have a device inbound. I really appreciate your instructional style. Keep pumping out relevant and helpful content!

@craigwestlake7362 2 years ago

My NanoVNA arrives next week! Another rabbit hole to explore.. Can’t wait now to experiment. Thanks Hayden.

@amham48 2 years ago

Terrific! Best demo I've seen on ferrites.

@richardowens9061 1 year ago

Remember, ferrite beads are typically sized for the intended application. And, you want your coax/wire/cable to have close contact with the ferrite material for best results. Pulling extra windings through the ferrite bead will increase contact with the core material, resulting in better performance - to a point, as you discovered.

And, you hit the nail on the head as to why extra turns stop helping and start decreasing performance. The capacitance of the turns combined with the inductance creates a resonant circuit at some frequency and its harmonics. This would become more clear, if you expanded the range up to 1GHz, or higher.

@mike94560 2 years ago

I set display scale to 3 so it is easier to find 3dB points. Nice video.

@beyondmiddleagedman7240 1 year ago

You've convinced me that I need to get a nanovna!

@RobCanada 2 years ago

Thanks for the video. I've had a NanoVNA for a while collecting dust as I have a bunch of professional antenna analysers but I am finding these videos fasinanting as to what you can do with these tiny units and it's spuring me to get mine out and play. I look forward to the next installment :)

@jerrym1183 1 year ago (edited)

When you are doing an amplitude measurement like this especially at higher 144 MHz it really helps the accuracy and dynamic range of the measurement to be sure to ground the "shield" of your RF in/out coaxial test leads together at the coaxial end of where your Ferrite under test is happening, this will give greater accuracy especially for 10/6/2 meters. Good Stuff!!

@MrApolloTom 1 year ago

9:47 Thanks, I also learned today that you can drag the pointer!

@bill-2018 8 months ago

Thanks for this, just what I needed.
RG58 with two FT140-43 in series, still r.f. with one so I added a second, another one at the tx.
Ranging from 42 dB at 10m to 25 dB at 160m with 36 at 10 MHz. Six or seven turns on each.
G4GHB.

@LifeAtTerminalVelocity 2 years ago

Dude you just solved a problem for me! Testing this was on my To Do list for the northern winter. Now I'm just going to implement your solution and be done with it.

@DD4DA 8 months ago

A very helpful video. It shows the handling and setup to messure an unknown ferrite. This method is also very good to messure the supression of a Current-Balun.

@RixtronixLAB 2 years ago

Nice video, thank you :)

@akiddoo8113 2 years ago

Excellent! Thank you

@will_doherty 3 months ago

Interesting stuff, thanks. One point that I noticed - if you are going to use leads on the VNA you ought to do all of the calibration steps with the leads connected, to get a proper calibration.