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Snap-On Ferrite Cores FIXED! 3dB → Only 1dB Difference (RF Choke Test)

Budget Ham Radio

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Snap-On Ferrite Cores vs Solid Cores – Full Follow-Up Test!

In my last video the snap-on Mix 31 ferrites were showing 3dB less attenuation than the solid cores. But after installing the SO-239 and PL-259 connectors, the snap-ons gained about 2dB. Now there's only a ~1dB difference.

In this video I test all 7 individual snap-on cores one at a time on the same piece of coax at 14.267 MHz using the NanoVNA. Then I stack all seven and compare to the previous test.

What caused the improvement? I walk through my thoughts on why the connectors made such a difference when testing the shield (common mode).

Key takeaway: For real-world use on assembled coax, there's not enough difference to matter on your radio. Choose snap-ons for convenience if you already have connectors on the cable.

00:00 Intro & Setup
02:33 Testing each core individually
08:26 Stacking all 7 snap-ons
11:56 Why the connectors changed the results
15:59 Final recommendation for hams

If this helped, please 👍 Like the video and subscribe for more ham radio test & build videos!

73,
Jerry KM4ZKB

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If you build or buy coax chokes for HF, this test will help you decide. Solid cores edge out on performance, but snap-ons are much more flexible if your coax is already terminated.

Thumbs up if this was helpful! Drop a comment: Have you noticed a difference between snap-on and solid ferrites?

Save money and build your own!

👉 * Link to items used in this video in my Amazon store *
https://www.amazon.com/shop/budgetham...

Source for the Mix 31 ferrite cores for RG8X coax *
Snap-On - https://www.mouser.com/ProductDetail/...
Solid Core - https://www.mouser.com/ProductDetail/...

👉 Previous DIY choke videos: Common Mode Choke (CMC) Build and Test

Subscribe for more ham radio builds, tests & tips! Hit like button if this helped your shack.

Thanks for watching! Hope you have a blessed day.

#HamRadio #ferriteCores #ferritebeads #CommonModeChoke #CMC #RFI #AmateurRadio #nanovna

20 Comments

@Rodney_AE5TX 6 months ago (edited)

Jerry, thank you for your great videos. This is just another example of your sharing knowledge and experience with the community and dropping real-world examples. I subscribed and look forward to all your nuggets of wisdom. 73

@joeforlingieri4146 6 months ago

Thanks Jerry. I love your down to earth style and to use what you have around the shack/workshop if you can attitude. It really brings home the true spirit of ham radio! Have a great Easter. N1JFF

@WECB640 6 months ago

Hi Jerry. Good to see hams experimenting and measuring their results! It's been my experience that while both solid and split cores perform the same, the solid type wins due to stability over time. The split core is very convenient, but the gap must be a solid connection and over time (thermal cycling, dust ingress, or mechanical tension weakening), that gap eventually creeps open and then the magnetic field collapses rendering the ferrites all but useless. It doesn't take much for this to happen. Even if one end has a few thousandths while the other end it tight, the circulating currents within the ferrite are diverted and the inductance is greatly reduced.

This is the price we pay for convenience. I have seen several operators who have snap on chokes on their mic cords to suppress RFI, only to find that that the RFI has once again returned. Once they remove the snap on choke, clean the mating surfaces, add additional spring tension and put them back in service, the RFI stops like it did when the choke was new. I hope that's helpful to the ham community. 73 OM Keep up the good work.

@Kevin-tt5wt 6 months ago

Your logic and methodical approach are great! Thanks for making this.

@ScottNB0W 6 months ago

Thanks for doing that work. After the last video, I was expecting to see a significant difference between a few of those individual values.
Happy Easter!

@hbox21 6 months ago

good work Jerry see you next time. 73,s from across the pond. M7LUR

@17chucksters 3 months ago

Thank you for your demonstrations and walking us through your experiments. I’m learning a lot. 73

@benjaminon5bgo636 6 months ago

Many thanks Jerry for your perseverance in your testing methodology !! That subject between ferrite types has harassed my mind for a long Time. Many Thanks for your great test ! Best 73s, Ben - ON5BGO

@kunjant75 2 months ago

Nice work. Learned a few things

@schrodyn 6 months ago

Love your videos mate. Keep it up!

@analog_guy 6 months ago

Good conclusion.

@k.c.sunshine1934 6 months ago

Nice empirical experiment. Thanks for your effort in documenting this demonstration. This is a "classic" demonstration of the problem-solving process.

@markrobinson7831 6 months ago

Great video, lots to think about.

@NC9I 6 months ago

Jerry, good to see they are good quality pieces. I think of one were to use large heat shrink you could keep out some contaminants and keep them tight on the coax.
Thank you for taking the time to test each one.

Nc9i
Brandon

@chuckfinley858 6 months ago

There is also a percentage of tolerance for these cores in manufacturing. I'll bet no string of cores will be exactly the same for this reason. It happens in virtually every electronic device. Thanks for the update. 73!

@TomL2040 6 months ago (edited)

Excellent test with clear results (20m is good choice to test since that is what many people use most in the field). Now, the next logical test is the use of a single large diameter toroidal ferrite (like FT-240) and pass the coax through it multiple times to see the improvement with each perfectly spaced turn. And separate tests for different diameters of turns of coax. And what happens when the turns are not perfect (cross-over each other) to see degradation of choking. ❤

@DK5ONV 6 months ago

Happy Easter to you and yours, Jerry. 73 de Uncle Günter across the Pond 💯👍🙋‍♂

@andrethomas1800 6 months ago

Probably the most significant difference between the two styles would be the behavior close to the point of saturation - which of course if you ever reach that in this particular application you have way bigger problems that some noise on the outside of your coax. Nice vid, thanks for sharing.

@nnasab 6 months ago

Thanks for the video, I usually just use the snap on models. K4NCC

@jpmiller8098 3 months ago

I suggest that the differences were due mostly to the small variations in the gaps in the core halves. Put a piece of paper in the gap of a core and you will see a big difference with that single snap-on core. Those cores will snap on slightly differently each time. I don't suspect the connector itself but it might have changed the length of the cable slightly. The 1.35 dB initial value is due to the inductance of the loop in your test setup. What looks like a smiley mouth on screen is a loop of wire in air. Its inductance is proportional to the area of that loop. That gives an attenuation that increases with frequency with 1.35 dB at 14 MHz. If you squeezed those wires closer together like a closed mouth smiley face, you would get less attenuation. You did well to keep it in just about the same position throughout your tests so that would not be a variable. But you did make it more open in this test than in previous tests by extending the ground wire and possibly by adding the connectors. W5PZT