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Author Topic: Effect of low SNR (Max adsl)  (Read 24138 times)

soms

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Re: Effect of low SNR (Max adsl)
« Reply #15 on: October 29, 2006, 11:32:50 AM »

This whole ferrite clip idea will be interesting. Perhaps you are launching a whole new field of improving line stats or maybe nothing will happen at all  ;) We'll just have to wait and see!
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kitz

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Re: Effect of low SNR (Max adsl)
« Reply #16 on: October 30, 2006, 10:47:18 AM »

:) I think I've cracked It!  ......... /snip

Just thought I'd share this info' - might help someone else.

Glad you got it sorted canon and things are better...
thanks ever so much for letting us know. :)
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kitz

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Re: Effect of low SNR (Max adsl)
« Reply #17 on: October 30, 2006, 10:49:16 AM »

Check this out, my buddy in the netherlands, he connected a ferrite block to the cable that immediatly comes out of the phone socket and he said he has got a better sync speed and also a faster download speed.

The ferrite blocks are on everything nowadays and are for interferance, monitors have them, basically everything has them nowadays.

He says it has helped him a great deal, so maybe its worth a try to a few ppl here ?

The ferrite blocks/rings are certainly an interesting concept..  I have seen a few mentions of them in the past, some people say theyve helped, others say theyve done nothing.

Its not an area that I know anything about but I suppose it depends on the type of interference, they certainly wont be able to help with noise already on the line itself but may help with "something" being picked up more locally.
The fact they are cheap encourages some people to give them a go.

My own view is that if you are getting the same noise margin from the test socket then they aint going to be able to help..  however it would be interesting to get some more info on this particular subject.
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canon

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Re: Effect of low SNR (Max adsl)
« Reply #18 on: October 30, 2006, 12:49:20 PM »

I've ordered 3 clip-on ferrite rings from Maplins just to try - as they're cheap. However I'm not expecting too much as, after re-cabling, I get Noise Margins the same as when plugged in the master socket. A ferrite ring may have an effect on the evening drop in margin and one on the router ADSL cable may help as it's amongst lots of other cables at the back of the PC.
I'll report back later.
« Last Edit: October 30, 2006, 12:51:28 PM by canon »
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EVIL-SCOTSMAN

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Re: Effect of low SNR (Max adsl)
« Reply #19 on: October 31, 2006, 04:01:15 PM »

Ok this is what my buddy says.

The cable that goes from phone to router, loop it, dont just bundle it up, do proper loops as any distortion in the cable can undo the work of the filters, you then take 1 filter and then put the loops threw it, the loop should contain  a few wires, as everyloop you do will add another length of wire that the filter has to go over.

basically like  say you do 3 loops, it would look like  O O O  close together, so the filter will have 3 wires going threw the centre of it. IT HAS TO BE LOOPS he says, if you ZIGZAG Bundle the cable then the info isnt going in one direction and can nullify the filters work.

He doesnt have snr values of before and after, but he says, his connection was always 19.100-200  without the filter, with the filter he gets 19.500 and at times 20mbit.

As I say he isnt the retarded kind to make this stuff up, he used to work as a Network engineer but is now onto making machines that make cpu's, so I guess he knows wtf he is talking about.

Whether it works for anyone else is unknown to me, as I havent tried it and thus I cannot say that it does or doesnt work, but there ya go.

I hope this helps.

--------

[slight edit by mod]
« Last Edit: October 31, 2006, 04:22:52 PM by kitz »
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kitz

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Re: Effect of low SNR (Max adsl)
« Reply #20 on: October 31, 2006, 04:25:52 PM »

Thanks for the additional info.  :)

Ive seen before about the circle loops and how it may well help if the noise is introduced on that section of the cable.
iirc Ive also seem mention of core blocks that clip around the wire.
There seems to be no hard and fast evidence with this..  hence why any results would prove interesting.
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canon

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Re: Effect of low SNR (Max adsl)
« Reply #21 on: October 31, 2006, 10:52:33 PM »

Report back on clip-on ferrite blocks - no difference!
However, note well that I had already upgraded my extension wiring to Cat5e and fitted a filtered master faceplate and thus obtained results the same as connected directly to the master socket. Who knows, I could have done it a lot cheaper with the ferrite.
I fitted 3: one behind the master faceplate on the first part of the extension cable; one on the extension cable just after the intermediate socket (in series) and one on the router ADSL (RJ11) lead near the router. (belt & braces).
I'll leave then there now, can't do any harm and may protect from any new source of interference.
I bought from Maplin who also do the ring type, they're cheap enough to try for anyone with low noise margins who cannot upgrade their wiring.
See: http://www.maplin.co.uk/search.aspx?MenuNo=77623&MenuName=FERRITES&FromMenu=y&criteria=FERRITES&doy=31m10

Maybe someone else will try it who hasn't got CAT5e cable.
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EVIL-SCOTSMAN

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Re: Effect of low SNR (Max adsl)
« Reply #22 on: November 01, 2006, 06:41:45 AM »

Sorry to hear that it didnt work, as i said before, I hadnt tested it personally, so I cannot vouch if it was any good or not, but going by your results it didnt work, but then going by my buddys results it worked, so I really dont know whats happening.

Maybe my buddy had inside interference and the blocks helped him due to the interference being in his house, rather than the incoming signal being borked, I really dunno.

I think I will buy some to check it out in anycase, I also think that it is only good for people who dont connect at the highest sync rate i.e. 8128, that would be my theory, as if you connect at that rate then you cannot sync any higher.

I have cat 5 5e and 6 cables, so I can try with the cat 5 to see if that makes difference.

But saying that, you didnt connect the blocks to your ethernet cable did you ? as what I was told it should go on the looped rj11 cable, but i spose the more on different cables the merrier :)

anyway, i will get some and test them out with cat 5 5e and 6 cables and see what the results are.

sorry it didnt work for ya :(
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roseway

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Re: Effect of low SNR (Max adsl)
« Reply #23 on: November 01, 2006, 07:37:11 AM »

Looking at the specs for those Maplin clip-on ferrites, I would be fairly amazed if they had any effect at ADSL frequencies. They are specified to give a certain amount of attenuation at 25 and 100 MHz, whereas ADSL operates at a few hundred kHz.  To get an effect at ADSL frequencies you would need much larger ferrites to get any worthwhile improvement just by clipping on a straight wire.

Eric
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man_beach

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Re: Effect of low SNR (Max adsl)
« Reply #24 on: November 01, 2006, 09:08:34 AM »

I tried a clip-on ferrite - no difference at all. Don't suppose it does any harm, though.
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kitz

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Re: Effect of low SNR (Max adsl)
« Reply #25 on: November 01, 2006, 04:19:23 PM »

Thanks for the feedback on this..
I think its quite an interesting debate and Im quite enjoying seeing the new information people are providing.

I think that in a similar way that removing the ring wire can help some people but not others.. its all down to the state of your internal wiring.

I still maintain that if your extension socket is giving the same line stats as that you can get from the master test socket.. then I dont see how ferrite blocks can possibly help improve things.
- Im quite happy to be proved wrong on this..  but I cant see how they can improve anything from outside your premises.

If there is a problem where noise etc is being introduced internally then they may move prove useful...  if you also bear in mind what roseway has said in his post above.

Anyone have any idea on what/how much difference coiling/looping makes?
Its not an area I know much about... but certainly an interesting topic of conversation.
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canon

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Re: Effect of low SNR (Max adsl)
« Reply #26 on: November 01, 2006, 05:47:39 PM »

Here are a couple of Google results about the use of ferrite rings to suppress incoming/outgoing interference. Not the ADSL field but indicate how it works. Obviously needs a 'tuned' application of the principles to work properly. seems  though a ferrite 'choke' (second reference) might have the opposite effect to what is required for ADSL.

http://66.102.9.104/search?q=cache:dNHP978fOGMJ:www.ct-consultants.org/newsletters/2002/newsletter_06_02.pdf+ferrite+ring+interference+reduction&hl=en&gl=uk&ct=clnk&cd=19

http://www.stefanv.com/rcstuff/qf200005.html
 Maybe there's an eletronic engineer out there who could design just the thing for an ADSL line with problems!
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roseway

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Re: Effect of low SNR (Max adsl)
« Reply #27 on: November 01, 2006, 07:13:22 PM »

The way that a ferrite clip works is actually quite simple. It increases the inductance of the wire, and the nature of inductance is that its impedance (ac 'resistance') increases with frequency. So at very high frequencies a ferrite clip can attenuate noise signals quite significantly, but it becomes progressively less effective at lower frequencies.

Much more effective is a ferrite choke, which is a coil of wire wound on a ferrite core. These can be designed to be effective at any frequency the designer chooses, and they are of course used in ADSL filter/splitters. The difficulty with adding chokes to your telephone wiring is that they have to be connected in series with the connections, which is not so easy to do neatly and effectively.

In my opinion, ferrite clips and chokes are a non-starter for dealing with ADSL noise problems unless you have the necessary electronics knowledge. Far better is to use a filtered faceplate and use Cat5e (or better) cable for all internal wiring. Unfortunately Cat5e cable isn't pretty.

Eric
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canon

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Re: Effect of low SNR (Max adsl)
« Reply #28 on: November 01, 2006, 08:22:47 PM »

Far better is to use a filtered faceplate and use Cat5e (or better) cable for all internal wiring.
That's what I did first and was very effective - was just interested to see if ferrite clips had any effect - none as I've already said.

Unfortunately Cat5e cable isn't pretty
The CAT5e 3 twisted pair I bought from www.clarity.it is white, not a lot different from standard phone cable. It goes out of the back of the filtered master socket wall box to the outside, runs in conduit up the wall & through the garage, into a bedroom to an intermediate socket (dual phone/ADSL) and then along skirting boards in mini trunking to the next room, again to a dual socket. Looks quite neat, no complaints from wife either!
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roseway

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Re: Effect of low SNR (Max adsl)
« Reply #29 on: November 02, 2006, 07:26:35 AM »

Quote
Looks quite neat, no complaints from wife either!

I guess your life wouldn't be worth living otherwise. :'(

Eric
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