Microfilters constantly keep failing?

Hi everybody

I've been having some issues with my broadband ADSL connection which has been persisting for some time. I've tried almost everything I can think of, but I have no idea what is happening.

A year or so ago, I started to have a significant number of disconnections and a reduced ADSL speed (up to six disconnections a day and the speed below 1MBPS, compared to about 4MBPS at it's peak). The speed seemed to rise and fall persistently with no obvious cause. I contacted BT and they came out and changed the telephone box, claiming it was faulty. They also tested my microfilter and found it was defective and I produced another which they claimed was fine. After this, the internet connection speeds and connectivity were vastly improved.

About three or four weeks later, I started to experience the same disconnections and speed drops which progressively became worse. I changed just about everything I could think of, but nothing was working. I then noticed that when I changed the microfilter, the problems seemed to clear up temporarily and then resume their previous pattern. After some tests, I've discovered that the microfilters seem to fail consistently after a few weeks.

I'm at a bit of a loss as to why this is happening, so I wondered if anybody here might have any ideas as to what is going on? I've replaced about six or seven of them now of all different brands and configurations and nothing seems to help. At this stage, I just want the connection to work properly as designed

If anybody could help me, I'd appreciate it

Thanks

Filters should last years

What you your line stats from the adsl modem?

In reply to a post by Cycle194:

I've replaced about six or seven of them now of all different brands and configurations and nothing seems to help.

Therefore it's not them!

What is causing the filters to fail? An interesting question.

Have you tried changing the modem/router/hub that is connected? It may have a fault and be putting out a high DC offset voltage, for example. Or is the connected phone one which has a power supply - that could be doing similar ...

Or what about the cat marking territory? A bit extreme, but it could appen!

Had not thought of the CAT possibility!

Afternoon Cycle 194
To follow up on MHC particularly, basically the Splitters do NOT have filters directly in the ADSL path, which if you have the right equipment, you can demonstrate partly by the simple electrical continuity through that side; and also if you have a suitable simple adaptor and plug a phone in to it, the phone will work.


It is the "PHONE" outlet from the Splitter that has a a filter in it - to prevent the High Frequency ADSL signals coming through that Splitter PHONE socket - a High-Frequency Rejection Filter technically.

(Traditional Phone usage, voice particularly, is all at LOW Frequencies, hence the need to keep the HF ADSL away from the phone etc.)

If you plug a Modem/Router in to that Splitter PHONE Outlet, depending on the quality of the HFR Filter, the Modem should NOT work, although occasionally it may need two splitters in series.

I have actually tested those combinations some months back - having suitable equipment.

Also last night noting your problems, I managed to open up a splitter, confirming that the ADSL side is straight-through; and the PHONE side is through the HFR Filter.

----------------------

As MHC has suggested, you should check the other equipment, both of a computing variety and also of the traditional phone/fax/alarm variety.

As you first encountered the problem about one year back, it may be a new item that you added about that time - but ...

One way and probably the easiest would be as your ADSL connection starts to deteriorate often enough to be easily/quickly observed, disconnect all the other equipment, one at a time, to see if you note any improvement for your modem.

I acknowledge that this could be a protracted exercise, possibly having to wait weeks for the condition to arise.

-------------------------------

You may be able to get a clue more quickly, by carrying out several Quiet Line Tests, starting simply with a corded phone hand set connected in to the NTE etc, gradually adding each bit of equipment and retesting to see if any specific bits (and there may be more than one) are injecting noise in to the line - again tying in with MHC's thoughts.

--------------------------------

But No Guarantees - it could be lengthy, unfortunately.

Edited by deleted (Wed 03-Dec-14 12:29:28)

Thanks to all of you for your posts and suggestions.

To reply initially to MrSaffron, my current ADSL stats are as below (I showed two readings an hour apart). As the speeds vary quite often, they are likely to change quite regularly though.

Operational Mode - G.DMT
Upstream - 800 - 800
Downstream - 2048 - 2016
SNR Margin(Upstream) - 11.0 - 11.0
SNR Margin(Downstream) - 4.3 - 5.8
Line Attenuation(Upstream) - 28.0 - 28.0
Line Attenuation(Downstream) - 52.0 - 52.0

I'll reply to the other issues below in brief:-

* I have changed everything relating to the Internet connection over time, the cables, the router, the telephone system and nothing has seemed to make any difference. Even the phone box has been changed by a telecommunication engineer without resolving the problem.

* There is no cat or other pet here, so we can rule that out as the problem

* I have conducted several quiet line tests and the line seems completely clear, I can't hear any obvious noise or interference.

* I suspect that incoming calls relate to the problem, which is unsurprising. I have seen the Internet disconnect if a call comes in, although it disconnects at other times too. Having the phone unplugged from the microfilter and hence the line seems not to resolve the problem. I tried to plug the modem router directly into the line, thus removing a microfilter completely, but I couldn't find an RJ11 cable that worked. I could use an RJ11 to BT adapter though to try it.

* Nothing was changed on the connection or phone side when the problems started occurring, it had been static for quite some time before that.

Your responses suggest other possibilities I haven't been able to test yet:-

* Having eliminated the router or phone as a possible cause for blowing the microfilters, is it possible that a charge from the line itself is causing the issues?

* The possibility of plugging the modem into the Phone section of the filter was suggested, presumably as a microfilter test. That might be worth pursuing, I'll order an apropriate RJ11 to BT adapter. Does anybody know where I could get a microfilter tester from, or if I could devise some kind of test with a multimeter?

I know this process will take a long time, it already has, it would just be nice to think I'm on the right course and not lost for ideas

Thanks

Morning Cycle

You certainly have pursued quite a few possible causes.

To extend from MHC's cat possibilities and voltage injections, I wonder if your phone line runs through areas where it could pick up stray voltages such as temporary electric fencing in fields, its location being changed to suit grazing conditions.

Although clearly not your problem as such, intermittent use gave rise to problems with an intended ultra-stable table for testing inertial navigation equipment. The source was eventually traced to a factory over 1 mile away (1.6 KM), only occurring when a particular piece of heavy machinery was being used.

But it could be other electrical equipment only used occasionally.

A possible source could be an electrified railway line (including sidings), used occasionally for diversions etc; but again this is only to broaden the scope.

Are you aware if neighbours have similar problems?

Based on the connection speeds your line has been banded, which limits the upper and lower sync speeds to try and make a line more stable.

Sometimes the banding is too keen and http://www.coolwebhome.co.uk/calc will show that if the line was to be unbanded it would go faster.

My advice, pester ISP to get the line unbanded and see how it behaves, if it reconnects a lot and you end up banded again then you have some noise/interference to investigate further.

The neighbours on one side are not experiencing any issues at all. The neighbour on the other side is having all manner of connection issues and has never attained more than half of the sync speed of the other two properties, and frequently much less. I've been trying to help them with their issues too without much luck. Given their other troubles and the fact I don't live there, it's much more difficult for me to work out if they also have microfilter problems, particularly since they aren't technically minded. But I'll do what I can to find out.

Is there any kind of surge protector I could buy that might help me diagnose such an issue? I know they make standard ones with phone sockets, but I have a feeling they are looking for much higher surges.

MrSaffron, you are correct that the line has been banded. On a previous occasion, I was diagnosing this issue, I contacted my ISP because the speeds were not improving. They acknowledged that the connection was banded and unbanded it which sped it up quite considerably. However, given the problems I'm having, it seems clear that they have re-banded it, probably due to the instability of the line.

I have previously set up a Raspberry Pi to monitor the number of connection drops I receive in a single day. It only checks every hour and so 24 is the maximum number of drops it will report. As a guide, the connection has been dropped the following number of times recently:-

3rd of December - 7
2nd of December - 14
1st of December - 5
30th of November - 0
29th of November - 12
28th of November - 13

The figures are much worse than I had reported, it seems the problem has become more prominent. This seems consistent with earlier experiences, could a microfilter become worse over time?

Any advice anybody could give would be most useful. I'm almost at a loss at this stage.

Thanks