On Sun, 07 Mar 2004 00:05, Patrick Dunford wrote: > Christopher Sawtell wrote: > >On Sat, 06 Mar 2004 23:35, Patrick Dunford wrote: > >>Christopher Sawtell wrote: > >>>Got caught by the flippin' Reply-To: again. Sorry > >>> > >>>---------- Forwarded Message ---------- > >>> > >>>Subject: Re: [OT] LAN cable tester in Christchurch to borrow please > >>>Date: Sat, 06 Mar 2004 21:12 > >>>From: Christopher Sawtell <[EMAIL PROTECTED]> > >>>To: [EMAIL PROTECTED] > >>> > >>>On Sat, 06 Mar 2004 18:00, Yuri de Groot wrote: > >>>>Hi, > >>>> > >>>>Does anyone have an advanced LAN cable tester I can borrow > >>>>in Chch? > >>>>I have one that tests each of the 8 strands for electrical > >>>>conductivity, but it does not test ability to carry ethernet > >>>>traffic - if ya know wha I mean. > >>> > >>>I came across a very similar situation to your's a while ago. > >>>After much confusion with very odd intermittent faults it transpired > >>> that the poorly put together Ethernet wiring would happily carry 10MHz > >>> signals, but not 100MHz. Sometimes the net worked ok as a 10MHz net, at > >>> others it failed as a 100MHz. We were confused for quite a while. After > >>> rewireing it properly, it worked perfectly. > >>> > >>>The point of the story is that it might be worth your while putting an > >>> old 10MHz card in one of the machines to force your net to run at > >>> 10MHz. If it works at the lower frequency, then that more or less > >>> proves that you have problems with noise on the cable run. > >> > >>What can cause noise on network cables? > > > >Cross-talk from the mains would be the most usual. In any situation > > remotely 'industrial' the mains wiring can be a real noise generator. > > > >As a previous poster stated running Ethernet close to mains wiring is > > usually the problem. imho, At least 50 cms in practice leave at least one > > stud space between them in a wall. > > What about patch leads and power leads of computers running close together?
Bundled up together in a nice neat cable run would not be a good idea. It's running the Ethernet and mains wires parallel for any distance that causes the problems. A few cms, like through the the cable feed hole in a desk is ok, but tying the wires together for metres is death for the Ethernet signal. -- Sincerely etc. Christopher Sawtell NB. This PC runs Linux. If you find a virus apparently from me, it has forged the e-mail headers on someone else's machine. Please do not notify me when this occurs. Thanks.
