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Author Topic: Interference  (Read 5780 times)

Woppy101

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Interference
« on: September 23, 2011, 07:50:07 PM »

Can a power socket cause snr drops and interference?I'm having random snr drops at first I thought it was my heating but I have just had a drop 30mins before the heating has come on,it can't be the street lights because they have never been on/due to switch on or off during any drops.the only thing I can find is when walking round with a untuned radio the plug next to the master socket buzzes like hell, the socket is switched off but still buzzing,when I put it next to another socket that is switched off there is no sound  anyone got any ideas
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waltergmw

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Re: Interference
« Reply #1 on: September 23, 2011, 11:51:05 PM »

Hi Woppy and welcome,

Are the SNR drops causing your modem to drop and re-sync ?

If not, I wouldn't bother as actual ambient noise varies naturally, thus affecting the signal to noise ratio.

Kind regards,
Walter
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burakkucat

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Re: Interference
« Reply #2 on: September 24, 2011, 12:14:42 AM »

. . . with a untuned radio the plug next to the master socket buzzes like hell, the socket is switched off but still buzzing . . .

Could it be that you are picking up a signal that is being radiated by wiring to & from your master socket and not the power socket?

The most obvious test would be to power off your modem/router and check with the radio. If you still detect "buzzing", then turn off your electricity supply at the main and check again. If the "buzzing" is still present, then it cannot be anything to do with your mains socket but is a signal being induced into your telephony pair, somewhere exterior to your home.
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Woppy101

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Re: Interference
« Reply #3 on: September 24, 2011, 07:23:43 AM »

Hi Woppy and welcome,

Are the SNR drops causing your modem to drop and re-sync ?

If not, I wouldn't bother as actual ambient noise varies naturally, thus affecting the signal to noise ratio.

Kind regards,
Walter

Yes it does cause me to re-sync,the thing that's annoying is I'm in my 10days(for the 3rd time)and I don't want the exchange to see the drops as an unstable line when its not
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roseway

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Re: Interference
« Reply #4 on: September 24, 2011, 08:03:10 AM »

I hope you won't mind me saying that it wasn't the best idea to go for a retrain while the connection is unstable. You'll probably end up with a fault threshold rate which is lower than it should be, and maybe an increased target noise margin.

In addition to the above suggestions, I would move the router as far away from the suspect socket as possible (and power it from somewhere else), even if you have to use a longer ADSL connecting lead to reach the phone socket.
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  Eric

Woppy101

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Re: Interference
« Reply #5 on: September 24, 2011, 09:05:18 AM »

There was no option because my line card failed in I ended up with an ip profile of 125kbps,is it the master socket,cable or router that picks up the interference and causes the re-syncs?
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waltergmw

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Re: Interference
« Reply #6 on: September 24, 2011, 10:15:15 AM »

Hi Woppy,

It's impossible to say absolutely but cables are often the pick-up point and, in any case, are the only things you can change to any great extent.
Do ensure that you've removed the ring wire as described in Kitz's troubleshooting guide here.

http://www.kitz.co.uk/adsl/troubleshooting.htm


However it is wise to position both wires and the modem as far away as possible from mains cabling and other wireless devices such as DECT cordless phones.

Kind regards,
Walter
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roseway

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Re: Interference
« Reply #7 on: September 24, 2011, 10:28:12 AM »

[Walter posted while I was writing this, but I'll post it anyway]

It's hard to tell exactly where the interference is being picked up, so it's really a matter of elimination. If you move the router well away, and power it from a different socket, that will eliminate one possible route (dodgy mains socket --> router). You could buy a good quality twisted-pair cable for connecting the router to the phone socket, and this would eliminate the cable as the source of interference pick-up. The cables listed here as 'High quality' are the sort of cable I mean.
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  Eric

Woppy101

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Re: Interference
« Reply #8 on: September 24, 2011, 10:42:18 AM »

I already have a high quality twisted pair modem cable(was the first thing I bought when the problems started)I have just went round with the radio again,in my foyer there is the master socket then a plug socket then some heating pipes the go from floor the celing,the radio buzzes like hell floor the celing when next to the pipes,is there anything I can use to insulate the pipes?
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roseway

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Re: Interference
« Reply #9 on: September 24, 2011, 10:50:46 AM »

Central heating pipes should be earth bonded to meet electrical safety regulations, and I would have thought that this would stop them radiating RF interference, but I've no personal experience of this.
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  Eric

Woppy101

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Re: Interference
« Reply #10 on: September 24, 2011, 05:41:50 PM »

But getting back to the interference I put an old dg834g v3 on this morning(renowned for holding a sync even past 0db and a TI chipset same as the exchange), and I had a burst of interference at 1400hrs where the snr was at 0db for around 6minutes and it managed to hold without a re-sync(touch wood lol)!
Even though I will only be 3days into my training period should I report a REIN fault to idnet on Monday?
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jeffbb

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Re: Interference
« Reply #11 on: September 24, 2011, 06:16:16 PM »

Hi
You really need to have more info to be sure you have a REIN problem. Try routerstats  . This is a usefull troubleshooting tool. You can plot The snr Margin anf synch rates over any time frame required , and as its plotted as a graph will help to Identify REIN(normally very spiky )  or otherwise .

Regards Jeff
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Woppy101

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Re: Interference
« Reply #12 on: September 24, 2011, 06:49:50 PM »

Hi
You really need to have more info to be sure you have a REIN problem. Try routerstats  . This is a usefull troubleshooting tool. You can plot The snr Margin anf synch rates over any time frame required , and as its plotted as a graph will help to Identify REIN(normally very spiky )  or otherwise .

Regards Jeff
That's what I'm using to track the snr,the graph on the spikes looks like when you see an earthquake plotted in the movies,I'm taking print screens of the spikes to show my ISP 
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