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Strange noise fault

ajbrown1965
Grafter
Posts: 121
Registered: ‎27-02-2009

Strange noise fault

Can anyone throw any light on my problem and offer a possible solution?
My set-up is as follows: the only socket in the house is the BT Master socket; the broadband router is connected to this, and also a (new) telephone base unit with answerphone. The only other phones are two remote handsets connected wirelessly to the base unit. There is no other telephony equipment, and no extensions. Over the past year BT have completely re-wired from the point where the line comes into the house (about 8 metres from the master socket) back to the exchange. At the moment the router and phone are connected through a filter straight into the test socket behind the master socket faceplate.
The problem is that everything works fine for 3 or 4 days; SNR margin stays fairly steady at 6 - 7dB and the BB speed is steady with a profile of 5500, the best it's ever been for over 5 years. Using the telephone has no effect on the BB. However, after a few days like this the SNR will drop to 5dB or below, and as soon as the phone is in use it drops even lower, and also there is a lot of hiss and crackle on the line. If I change the filter between the router/phone and test socket the line noise immediately disappears and all returns to normal for a few days. It doesn't seem to make any difference which filter I use; I have 5 currently availalbe of various makes and designs, and can randomly switch between them, even using ones which were in use on a previous occasion.
If I realise there is a problem I can change the filter in time to lose the BB, but if I'm too slow the profile drops as low as 1500 and it takes a couple of days to build it back up.
I'm certain the fault is either in the house or between the master socket and the point where the line from the distribution pole reaches the side of the house, as everything else has been physically changed.
Any observations or suggestions would be most welcome.
10 REPLIES
pierre_pierre
Grafter
Posts: 19,757
Registered: ‎30-07-2007

Re: Strange noise fault

sounds like BT have a "dry" joint that is burnt in when you remake your phone connection.
Who is your phone supplier?,  report the fault to them as a phone fault, do not mention broadband
ajbrown1965
Grafter
Posts: 121
Registered: ‎27-02-2009

Re: Strange noise fault

Phone supplier is Plusnet. I'm a bit loathe to raise a fault as they have been working on my problems for over a year now on and off and they maight be getting fed up with me.
I'll be away for a couple of weeks so BB and phone won't be used, so I might wait until we get back and see what the situation is then.
matt_2k34
Grafter
Posts: 1,300
Registered: ‎09-07-2007

Re: Strange noise fault

Quote
Phone supplier is Plusnet. I'm a bit loathe to raise a fault as they have been working on my problems for over a year now on and off and they maight be getting fed up with me.

You have a problem, report it Smiley
I dont think they'll bump you off, theyve sorted several problems out for me since '01
Dont go without a quality service for fear of any issues that they arise, you pay for a service, you shouldnt have to keep doing several "bodges" to get it to function.
ajbrown1965
Grafter
Posts: 121
Registered: ‎27-02-2009

Re: Strange noise fault

Thanks, Matt. I'll take your advice as soon as I get home from holiday. This is really the last little glitch after what has been a long path to a good BB connection, and as you say it's worth having it sorted.
I agree - Plusnet are one of the best.
Plusnet Alumni (retired) orbrey
Plusnet Alumni (retired)
Posts: 10,540
Registered: ‎18-07-2007

Re: Strange noise fault

Hi aj,
With phone faults an engineer visit is often arranged on the same day as the fault is raised so it'd definitely be worth waiting until someone's available to be in the premises. Let us know when you're back and we'll get some tests done for you and see what's happening.
ajbrown1965
Grafter
Posts: 121
Registered: ‎27-02-2009

Re: Strange noise fault

Thanks, Matt, for the support. I'm pretty sure the problem must be between the junction on the outside of the house where the wire from the distrubution pole comes in and the master socket - it's the only thing that hasn't been replaced! Although I suppose it is possible for the master socket itslef to develop a fault.
I've got a couple of other things to try if the noise reappears before we go away; I haven't tried just unplugging the phone or rebooting the router, I've always replaced the filter when the nboise suddenyl starts. For some reason last night my router stats show a disconnection almost continuously between 1.00a.m. and 4.30a.m with no resysncs or anything. Possibly BT working somewhere. It hadn't affected the speed or IP profile though.
I'll raise a ticket as a phone fault when we're back in a couple of weeks time.
ajbrown1965
Grafter
Posts: 121
Registered: ‎27-02-2009

Re: Strange noise fault

Just an update. We were away for two weeks and I left everything disconnected, no change in IP profile during that time. However, the intermittant noise problem was still there, and so I installed a new Master Socket (don't tell BT) and, touch wood, this has solved the problem. No random dropouts and no noise on the line when the phone is in use. The SNR fluctuates bewtween about 6dB and 4.5dB over a 24 hour period, but I imagine this is normal with contention ratios etc. particularly during the evening.
I'll probably regret saying this, but after more than a year of problems, I might now have a stable BB setup!
jojopillo
Grafter
Posts: 9,786
Registered: ‎16-06-2010

Re: Strange noise fault

That's great news, ajbrown1965. Persistence pays!
Jojo Smiley
x47c
Grafter
Posts: 878
Thanks: 1
Registered: ‎14-08-2009

Re: Strange noise fault

Quote from: ajbrown1965
The SNR fluctuates bewtween about 6dB and 4.5dB over a 24 hour period, but I imagine this is normal with contention ratios etc. particularly during the evening.

The SNR margin will always get worse during the evening and overnight, returning to "normal" once the sun is up the next day.
As it is the margin getting lower this means the general noise level is getting worse overnight.
It has nothing to do with contention ratios but is a 'feature' of planet earth and is all to do with the "Heaviside layer" in the atmosphere - a layer of inoised gas some 75 miles up.
During the day the solar wind pushes the Heaviside layer closer to the Earth, thereby limiting how far it can reflect radio waves: and by extension how much general noise there is in the atmosphere. On the night side of the Earth, the solar wind drags the ionosphere upwards, thereby greatly increasing the range which radio waves can travel by reflection off the layer. Hence you receive longer distance radio stations - but with it you get more "noise" during the night which is picked up by the phone line which is in many respect an aerial.
The extent of this will depend on sunspot activity and it also varies with the seasons on the earth.
As regard broadband.............
Those phone lines which are predominately underground will be less suspectible to this sort of effect - conversely those customers with long overhead lines running from pole to pole being more exposed to this radio "noise" (and not being shielded of course) will have a larger variation between day/night SNR margin figures.  This latter category of customer are ones who might well benefit from turnining off the router each night, and thereby avoid it re-syncing at a much lower speed during the night due to the noise - and then not returning to a higher sync during the day....instead they switch on each morning when the SNR margin on their line will have improved to the 'daytime rate'
ajbrown1965
Grafter
Posts: 121
Registered: ‎27-02-2009

Re: Strange noise fault

x47c - thanks for the scientific explanation, which I should have been aware of as a retired Science teacher! At the moment the router isn't losing sync overnight, but I take your point about switching off and will do so if necessary.