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Re: [Fwd: Re: LAN noise?]



Data over a CAT 5 cable is high speed.  Ferrites impede changes in
directio on current flow.  The higher the speed the more the impedement
of change, up to the point of saturating the ferrite.  If the ferrite is
to be efficient in eliminating radiated lAN noise, it will also be
efficient at reducing the amplitude on the LAN.  This may be ok for very
short distances, but, over a longer distance the signal may be
attenuated enough to cause errors.  At the least the nice square waves
that the LAN card generates and looks for will become more like sine
waves.

Glenn
WB4UIV


Franklin Antonio wrote:
> 
> At 09:21 AM 6/1/99 -0400, Al Lawler wrote:
> >I used to get RF pickup from the keyboard, but that eas easilly cured with
> >a ferrite bead,  although this would probably degrade the performance of a
> >lan cable...)
> 
> In my experience, twisted pair LAN cables work just fine with ferrite beads
> on them.  When I wired my house, I put ferrite beads around the cat-5 cable
> behind every wall jack.  I also put them on the cables at the hub end
> before I crimped on the connector.  I bought a huge bag of ferrite beads at
> a swapmeet once that fit nicely over the cat-5 cable.  Also fit nicely over
> the burglar alarm cables.
> 
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