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[sevenlayermuddle]

How much will an insurance company pay for your lost time and lost data?

Data loss can occur for many reasons other than lightning strikes.  Surge protection doesn't remove these other risks, and doesn't remove the need for regular backups.

Same solution can be installed by a homeowner.

In England and Wales we have something called Building Regulations Part 'P' that stops the homeowner from doing much more than changing a lightbulb without calling in an Electrician.  I'd imagine (anybody confirm?) that protection on the AC mains would need to be installed at the incoming electric feeds, and so I''d be surprised if Part 'P' allowed the homeowner to do it himself.

And don't forget the TV arial as a conduit for surges, it's not just phone line and mains.

[westom]

It would perhaps be helpful if you could provide some links to protection equipment suppliers in the UK and detailed installation instructions

  That was provided in posts on 15 and 16 May.  One paragraph started:
> As noted, house grounding must be part of the earthing ...

  Even if you don't personally do the work, confirm work is performed properly; especially since these principles are little understood where damage is so infrequent or considered acceptable.  First and fundamental point, earthing is the central feature of a protection system.  The solution costs so little and routine when damage is not acceptable.  Obviously, costs are near zero if implemented first when concrete footings are poured.  Solution is always about diverting to where energy may be harmlessly absorbed.  A solution that is routine whereever damage cannot happen. Any recommendation that does not divert energy into earth is not an effective solution.

 Of course, the most important part of a useful answer are reasons why it works.

[hake]

Curiouser and curiouser

After 10 days uninterrupted service at 4704kbps down (SNRM 13.5db) and 448kbps up (SNRM 16db), synch was lost this evening and the stats are back to like they were before I removed the apparently offending surge suppressor.  The stats are now 4256kbps down (SNRM 16db) and 256kbps up (SNRM 7db).

Total mystification   

[roseway]

It looks as though the surge suppressor was a red herring then. Something else is apparently causing low frequency interference.

[westom]

Curiouser and curiouser

 The stats are now 4256kbps down (SNRM 16db) and 256kbps up (SNRM 7db).

As roseway notes, this problem is not due to unfiltered devices.  Something is probably imposing low frequency noise (25 to 130 Khz) on you DSL circuit (or their DSLAM is defective).  Those previous suspects (or an intermittent wire connection) would have diminished ownload signal strength.

[hake]

It was an amazing coincidence that the problem seemed to be resolved as soon as the surge suppressor was removed.  The disappointing thing is that things were working so well for so long.  I did however notice that three days before things went haywire, there were two intervals each with a lot of errored seconds but no disconnects.  I had a spike of errors at around the same time (c. 11.20am) about two days previously.

During this golden period, the downstream SNRM moved up and down between 13.5db and 15.5db.  The upstream SNRM remained constant at 16db, then BANG!.  It's down to 6db again.

?

[attachment deleted by admin]

[hake]

Thanks westom.  25+kHz would not be audible to humans on the quiet line test I think.  I will have to borrow a dog to listen for me.

[orainsear]

What make/model of router do you have?

[hake]

Thanks orainsear.  It is a BT Voyager 2100 (firmware version 2.18.01.17i_a023g1.d15g).

I am beginning to think that this is an impossible quest.  Lacking any devices which can measure and record the characteristics of my ADSL connection so that frequencies in the 25kHz to 130kHz range can be revealed, I am hitting the buffers.  Presumably, stumping up the £144 for a BT visit would bring such equipment into play.

Does BT possess systems capable of monitoring each copper loop to facilitate identification and diagnosis of problems?  BT seems to work on a presumption of its own infallibility and that problems can only occur on subscriber's premises (and no doubt many do as I have found previously on my own premises).  Since almost the entire cable run to and from the exchange is outside the subscriber's control, there would seem to be a degree of unreasonableness in this attitude often found with monopolies, such as appear to be held by BTw over its copper loops.

I imagine that the only way I could push this is to move to an ISP with LLU arrangements at my exchange but I do not wish to leave PlusNet who give excellent satisfaction in other respects such as tech support and facilities.  I am therefore stuck with BTw.

[HPsauce]

I imagine that the only way I could push this is to move to an ISP with LLU

Sadly, you imagine in vain. It's still BT's copper and the same people will look at it irrespective of your ISP. 

[hake]

So the UK digital economy is being held to ransom by a state protected private monopoly.   

The same high-handed attitudes used to prevail when it was part of the GPO.  Nothing has changed.

[orainsear]

I'd suggest trying out DMTtool by following this guide.  When you get it running we'll be able to get some graphs of your frequency spectrum

Don't play around with the SNR margin though - just get the line stats.

[rwm32]

Thanks orainsear.  It is a BT Voyager 2100 (firmware version 2.18.01.17i_a023g1.d15g).

I am beginning to think that this is an impossible quest.  Lacking any devices which can measure and record the characteristics of my ADSL connection so that frequencies in the 25kHz to 130kHz range can be revealed, I am hitting the buffers. [...]

I notice from your earlier post that you seem to be using DMT Tool v3.21 (with an exciting German interface...).

Perhaps you could try v8.07, which specifically lists your router -- and which might let you have a look at those lower frequencies. The DMT Tool version for my SpeedTouch 546 (see screenshot) shows the bitloading (though not the SN Margin) for the upstream connection. If you've got massive low-frequency interference, it /might/ show up as uneven bitloading... you never know.

The 30 - 300 kHz frequency range encompasses LW radio broadcasting, as well as things like RF ID tags and heart-rate monitors. You could hunt around the bottom end of the LW broadcast spectrum with an AM radio, to see if there's any hideous crackling, or a 1megawatt local radio transmitter 9km up the road -- which as you can see from the screenshot I have, broadcasting in the 960-970kHz range (not to mention R5Live on 909kHz...).  However, I think they are pretty much all in the MW band rather than LW.

Good luck, anyway!

rwm32

[attachment deleted by admin]

[hake]

Thanks rwm32.  I have wandered round the house with a portable receiver and scanned LW over the complete range the tuner allows me (upward of 150kHz).  I have to confess that I don't know what I am trying to hear.

These are the stats from the router: -

Line Mode   G.dmt       Line State   Show Time   
   Latency Type   Interleave       Line Up Time   00:19:52:30   
   Line Coding   Trellis On       Line Up Count   1   
   
   Statistics   Downstream   Upstream   
   Line Rate   4256   288   
   Noise Margin   14.8 dB    6.0 dB    
   Line Attenuation   38.0 dB    24.0 dB    
   Output Power   12.4 dBm    19.8 dBm    
   K (number of bytes in DMT frame)   134   10   
   R (number of check bytes in RS code word)   16   16   
   S (RS code word size in DMT frame)   1   8   
   D (interleaver depth)   32   4   
   Super Frames   4208557    4208555    
   Super Frame Errors   2    0    
   RS Words   286181892    35772717    
   RS Correctable Errors   150961    56    
   RS Uncorrectable Errors   17    0    
   HEC Errors   2    0    
   OCD Errors   0    0    
   LCD Errors   0    0    
   ES Errors   0    0    

I have attached an output from DMT v8.07.   Hope this tells you something.

[attachment deleted by admin]

[rwm32]

Well, I suppose it was worth a try with the v8.07 DMT Tool -- but the 'bit allocation not available' says it for me: it's not going to help. Sorry!

LW radio: if you de-tune your receiver from (say) R4 on 198, you should simply hear a hissing noise.  If there's something generating RF interference, you'll hear an unmistakeable crackling hum, totally distinct from the 'de-tuned' hissing.  However, upwards of 150kHz is taking you outside the suspect range, anyway.

Below 150kHz there are some defined bands for amateur radio operators (hams), plus a number of bands reserved for maritime navigational aids (Decca, LORAN).  So /if/ there is low-frequency interference hitting your upstream bandwidth, it might be because one of your neighbours is a ham radio operator... or perhaps there's a Decca or LORAN transmitter down the road (unlikely unless you're pretty near the coast)?

I'm rambling now, so I'll stop.

Rom