Ferrite Beads on video cables, when are they useful?

[Gara]

Do Ferrite beads on analog video cables have any benefits or disadvantages? Why are they on so many officially released cables?

Spoiler

They are on a lot of official RGB Scart cables for various systems that have Ferrite beads. I've also seen them on various Extron BNC cables, but only their "Mini High Resolution" line. The thicker "Super High Resolution" stuff doesn't have them. Would that indicate the filtering a Ferrite core is supposed to provide is only useful on cables with less shielding?

I'm really curious to hear peoples thoughts on this.

[maxtherabbit]

Do Ferrite beads on analog video cables have any benefits or disadvantages? Why are they on so many officially released cables?

Spoiler

They are on a lot of official RGB Scart cables for various systems that have Ferrite beads. I've also seen them on various Extron BNC cables, but only their "Mini High Resolution" line. The thicker "Super High Resolution" stuff doesn't have them. Would that indicate the filtering a Ferrite core is supposed to provide is only useful on cables with less shielding?

I'm really curious to hear peoples thoughts on this.

They act as common mode current chokes. The serve both to reduce emissions of, and reduce susceptibility to, RFI

[kitty666cats]

I once bought a fat bag of various sized clip-on ferrite beads; I picked through ‘em and attached them to all my ‘best’/‘keeper’ cables that I use in my permanent setup. Ideally you want to thread/loop them through said clip-on cores/beads. TBH I don’t notice a particularly discernible difference, but it was a cheap impulse buy and a good... “peace of mind” of sorts haha. I’d say it is worth picking up a cheap bag of various sized ones if you ever find yourself finishing a setup you know you are gonna have assembled for a good long while. The kinda thing you buy with the remnants of an Amazon gift card or whatever

[Gara]

They act as common mode current chokes. The serve both to reduce emissions of, and reduce susceptibility to, RFI

Yes yes, I read the Wiki. What I'm curious about is when do Ferrite beads actually benefit an analog video cable. What theoretical environment or variables did cable makers envision that they would choose to build them in to cables. Is it some kind of cargo cult thinking or do they actually have a real world benefit.

I personally see no difference in my setup by clamping or unclamping one from a video cable. If I lived in a radio station next to a cellphone tower then would that be different result? It's a long shot, but I figured I'd ask and see if anyone here has any theories or experiences to share.

I’d say it is worth picking up a cheap bag of various sized ones if you ever find yourself finishing a setup you know you are gonna have assembled for a good long while. The kinda thing you buy with the remnants of an Amazon gift card or whatever

This has been my approach. I had some, so I figured why not. I've always been curious to know if they actually do anything.

When searching through old posts there was one user here on Shmups that insisted they blurred the video signal when added.

[maxtherabbit]

I personally see no difference in my setup by clamping or unclamping one from a video cable. If I lived in a radio station next to a cellphone tower then would that be different result?

Yes. That's the only time they would benefit you. The main reason that manufacturers install them is for FCC compliance with respect to RF emissions. That doesn't benefit you as the user, but theoretically may benefit those around you trying to work weak signal radio contacts.

[Syntax]

Clip on ferrite cores don't really work. Waste of money.

For a ferrite core to be effective you need one that is an unbroken ring, and your wires need to loop around that at least once. (3x more effective)

Anything else is snake oil.

[XtraSmiley]

Did someone say beads....

[Konsolkongen]

Clip on ferrite cores don't really work. Waste of money.

For a ferrite core to be effective you need one that is an unbroken ring, and your wires need to loop around that at least once. (3x more effective)

Anything else is snake oil.

I believe it was Panasonic plasmas that used to bundle clip on ferrite beads for the power cables.

In my previous apartment I had an issue where every time the fridge would start the TV signal would drop out. I made a loop on the coax cable and clipped the ferrite bead on and it helped a lot. Almost completely eliminated the problem to the point where it was just a brief hick-up.

I later realized that I could get fully shielded plugs for the coax. That of course did fix it, without the ferrite bead. But they do work to some extend.

[Josh128]

^
Samsung plasmas also have ferrite cores on the power cables.

[Konsolkongen]

It was probably Samsung then. I’ve had both

[stuntman]

Clip on ferrite cores don't really work. Waste of money.

For a ferrite core to be effective you need one that is an unbroken ring, and your wires need to loop around that at least once. (3x more effective)

Anything else is snake oil.

A while back I had a cheap car dash cam that introduced audible noise to the radio. A clip on ferrite bead at either end of the power cable reduced this noise significantly. I'm sure the type of installation you suggest is better, but "anything else" may still be of benefit in certain scenarios (in my case a cheap, easy and effective fix).

[incrediblehark]

Clip on ferrite cores don't really work. Waste of money.

For a ferrite core to be effective you need one that is an unbroken ring, and your wires need to loop around that at least once. (3x more effective)

Anything else is snake oil.

I believe it was Panasonic plasmas that used to bundle clip on ferrite beads for the power cables.

In my previous apartment I had an issue where every time the fridge would start the TV signal would drop out. I made a loop on the coax cable and clipped the ferrite bead on and it helped a lot. Almost completely eliminated the problem to the point where it was just a brief hick-up.

I later realized that I could get fully shielded plugs for the coax. That of course did fix it, without the ferrite bead. But they do work to some extend.

My old 480p Panny plasma also, and came with extra ferrite beads for connections. Can't speak to their effectiveness but I haven't noticed any interference while using them.