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ferrite bead for ethernet cable


Razor512
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I have a 50ft cat 5

e ethernet cable that I am planning on installing for someone. The problem is that they have a lot of equipment that does introduce interference

I already installed ferrite beads on the sound equipment and power cables, but I wonder if I should install one on each end of the ethernet cable (cat 5 e says 350MHz but I am not 100% sure of all of the frequencies that may be in use on the cable and I want to find the right one for the cable.)

I want to make sure there no problems at all

which ferrite bead is the best one for a ethernet cable

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Ive seen them used in USB cables, but never in cat5 or any ethernet form. Would that even work with a length of 50 feet, if there is interference anywhere along that line length? I Thought they were used at the end of the cable close to the device itself to not cause problems with the device and cable connection at the cable end, not for shielding of the the cable length itself. If noise is cancelled close to the device ends, what happens to the noise introduced inbetween the ferrite ends?

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sound and video equipment seems to cause interference for the speakers. as things that have nothing to do with the sound will cause a slight noise. I was able to fix that but I am not sure if it will cause any problems for the ethernet.

everything seems to work fine when I hooked everything up, but it doesn't hurt to take all precautions

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sound and video equipment seems to cause interference for the speakers. as things that have nothing to do with the sound will cause a slight noise. I was able to fix that but I am not sure if it will cause any problems for the ethernet.

everything seems to work fine when I hooked everything up, but it doesn't hurt to take all precautions

I don't think it will help or hinder the signal. The twists in the cable are supposed to handle that. I've set up computers that had network runs go past very large three phase electric motors. The only way to get a signal to the computers was to run fiber. You could try running inside grounded metal conduit.

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That was my thinking, that the twists negate the need or use of ferrite and probably wouldn't even make a noticable difference in the network. If you want something better, then use cat6. Routing it by things that cause inerference will still cause problems with the communitcation, but you need to be generating a lot of EMI to cause problems in the signal. I doubt you will even need to resort to cat6 though.

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The Ferrite bead works by increasing the serial inductance of the wire to effectively low-pass filter out hf (RF) so a large enough bead will knacker gigabit ethernet cable. The twists help with common mode rejection but also depend on the quality of the differential input electronics of the interface. nuff said.

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I have a 50ft cat 5

e ethernet cable that I am planning on installing for someone. The problem is that they have a lot of equipment that does introduce interference

I already installed ferrite beads on the sound equipment and power cables, but I wonder if I should install one on each end of the ethernet cable (cat 5 e says 350MHz but I am not 100% sure of all of the frequencies that may be in use on the cable and I want to find the right one for the cable.)

I want to make sure there no problems at all

which ferrite bead is the best one for a ethernet cable

Why not run shielded Cat5? Ground one end only and that should take care of noise issues. However I think you'll find that this solution is only needed when running near 3 phase motors and VFD (Variable Frequency Drives).

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When I did CCNA, I was told that, whilst the maximum Ethernet cable length is 100m, I should use a maximum of 5m of stranded cable (at each end of a long run) and the remaining (upto 90m) of unstranded cable. The reason given was that there's much less interference with unstranded vs. stranded.

I've not seen this documented so it might have been one of those pearls of wisdom gained "on the job". I don't know if the OP's 50ft cable is stranded or not. It might be worth experimenting with a length of unstranded (if such a length is available to him/her).

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When I did CCNA, I was told that, whilst the maximum Ethernet cable length is 100m, I should use a maximum of 5m of stranded cable (at each end of a long run) and the remaining (upto 90m) of unstranded cable. The reason given was that there's much less interference with unstranded vs. stranded.

I've not seen this documented so it might have been one of those pearls of wisdom gained "on the job". I don't know if the OP's 50ft cable is stranded or not. It might be worth experimenting with a length of unstranded (if such a length is available to him/her).

I think someone was high when they said that.

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You can buy flat cat6, so its not like they have to be round cables, but its the twists that cancel the noise as well as the shielding. Ferrite beads may help reduce noise coming down the line but how much interference do you think you are going to get on the cable that will cause a problem? What are you running these cables around?

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I think someone was high when they said that.

I found some information (here and here) suggesting that solid UTP should be used for longer runs because the attenuation is less than with stranded UTP. I knew there was a reason to limit the length of stranded UTP cables.

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I found some information (here and here) suggesting that solid UTP should be used for longer runs because the attenuation is less than with stranded UTP. I knew there was a reason to limit the length of stranded UTP cables.

Okay, now I see what you were talking about. I thought you meant "unstranded" as in "untwisted" cable, like a phone cable. Most people don't wire buildings with patch cable, which is what the stranded cable is for.

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.... Most people don't wire buildings with patch cable, which is what the stranded cable is for.

Agreed. I don't know what the OP had in hand when mentioning a 50ft cat 5 cable. I would *assume* that such a length is solid ... but I might be wrong.

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