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[Weaver]

If I use double shielded - SSTP or SFTP - cable, can I get away with letting it touch mains cables?

Not lying parallel for a substantial distance.

I got hold of some (hopefully) Cat 6a cable from netshop.co.uk that has an overall foil screen and foil shields around each of the individual pairs.

[sheddyian]

I wouldn't worry.  It's pretty much going to work or it's not going to work.

If there is too much interference (unlikely) then you'll get significantly slower throughput due to retries etc. MUCH slower than expected. Otherwise it'll just work, and improving the shielding etc won't increase speed at all.

If you look at the reviews of HDMI cables in TV / Hifi magazines, where they say "oh this cable shows much better clarity, detail, colour" etc, it's nonsense.  It's digital.  it'll either work (= picture) or it won't (= no picture).  The fraction in-between will have massive dropout and corruption of picture which will be obvious to all.

Very similar with ethernet.

It works, or it doesn't.

Ian

[Weaver]

I realise I should have said, will any interference get through if using a screened cable? It sounded like a noob question?

[Btw, I know about TCP, all is well (-ish) if you are using it. Of course you may not be., and it's not like you have a choice. In my last job, I was (very briefly) joint Technology Group Leader for the Networking division at what is now known as Symbian (rip). It's difficult on the Internet, as you often don't have any clue who you're talking to.  ]

[Weaver]

Actually, could use TCP as an error rate meter. do a fast LAN transfer and see if you can make the speed drop by adding in a possible source of interference. Do it with UTP and then SFTP and compare.

Has anyone ever tried laying UTP next to mains, parallel, to see how much of an effect there is?

[Weaver]

In fact has anyone got any experience of any kind of doing the bad things: mains touching, crossing over at right angles (-ish); or even mains laid parallel ?

[sevenlayermuddle]

If you look at the reviews of HDMI cables in TV / Hifi magazines, where they say "oh this cable shows much better clarity, detail, colour" etc, it's nonsense.  It's digital.  it'll either work (= picture) or it won't (= no picture).  The fraction in-between will have massive dropout and corruption of picture which will be obvious to all.

An example of what amazes me about these magazines is they still insist that cables are somehow directional, speaker cables have to be connected the right way.   

Back in the 1970s, when everything was subjective and hence ill-defined, while it had no credibility among those qualified in electronics I'd just laugh at them, and buy the next issue.   But nowadays, when their nonsense is so much more quantifiable as nonsense, I begin to despair.   

[sheddyian]

Back in the 1970s, when everything was subjective and hence ill-defined, while it had no credibility among those qualified in electronics I'd just laugh at them, and buy the next issue.   But nowadays, when their nonsense is so much more quantifiable as nonsense, I begin to despair.   

I agree, although with analogue signals, and particularly with below-spec cables, there is an improvement to be had from using at-spec or (maybe) above-spec cables.

Early days of digital TV, I had a digibox connected to an analogue TV with a Scart cable.

The original Scart cable, as supplied, was a bit thin, probably didn't have individual screening between signals.  Quality was poor, shadowing on picture, occasional interference.

Replaced with a fatter (but not premium priced) Scart cable that had individual screening (between video and audio signals, for example).  Interference went away.

I then wired my own Scart cable with 75 or 50 Ohm (actually can't remember the required spec, but I followed it at the time) cables for video and appropriate for audio. I got a noticeable improvement in video quality and sharpness.

Wanting to go one further, I then bought some "oxygen free" cables etc, getting obsessive about it all.  Made up a new cable with the much more expensive wires.  No difference.

My conclusion from all this - once you're at spec, you're not going to make it any better. 

Ian

[Weaver]

I'm not a believer in the hifi voodoo con stories.

But interference on an ethernet link can corrupt bits and so make packet checksums fail. TCP is not used universally, there are other protocols that do not have retransmissions, so when packets get dropped because their checksums do not check out, then the packet loss is irrecoverable, without some possible kind of application-layer intervention, if available.

[Weaver]

I've always told customers never to run UTP next to mains, not touching in parallel. I think that's uncontroversial, standard wisdom, is it not?

If it's over the top, then I don't care as I just want to _err_ onnthe safe side, and not risk possibly getting any callouts because of network strangeness or mysterious slowness.

[Weaver]

Ridiculous hifi voodoo nonsense claims is an interesting topic, but off-topic for this thread. Should do a split as it's worth discussing. (The huge amount of money charged for such pack-of-lies-based products is big motivation. Two hundred quid for a mains lead, special feet under an amp, that kind of thing. Directional cables have also been mentioned. Utterly bloody ridiculous.)

[AArdvark]

I call it 'Magic Science' !

I cannot believe people can still get away with it.

Just check the science on the web.
Very easy to debunk the nonsense.

[Weaver]

Neverthess, getting back to topic, I would be interested to hear of users' experience, and if people are up for a TCP + UTP + mains challenge experiment, then I would love to hear the results.

[JGO]

If I use double shielded - SSTP or SFTP - cable, can I get away with letting it touch mains cables?

IEE wiring regulations used to forbid anything sharing a route with power cables, for the excellent reason of electrical safety !
I don't see any change in technology to nullify this sensible precaution, can anyone confirm it is still in force ?





 

 

[Weaver]

@JGO - I mind you, I am just talking about informal patch cables just laid out however so that mains happens to be beside ethernet cable sometimes. I'm not talking about a structured layout in ducts. When patch cables are lying around they tend to move about as the cats and the occasional human mess around with them. You can't always trust them to stay where they're put and to stay away from mains.

[Weaver]

Where do kitizens get their network cables from? Any good tips for web shops?