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[waltergmw]

Gentlefolk,

The General is plodding on with his one-man quest for the answer to the village REIN problem.

http://winterbournestoke-thedigitaldivide.blogspot.com/

He's invested in a Wi-Spy wireless sniffer and can see the results of the REIN at least in the 2.4 GHz frequency band.
He concludes that the noise is injected via his phone line and wonders if this signal is affecting the DSLAM as well as the modems.

Is anyone able to offer him any other clues ?

Kind regards,
Walter

[sevenlayermuddle]

Hi Walter, some thoughts...

I must confess, I'm a little bit sceptical of the suggestion that a 2.4GHz signal would be propagated any distance in a phone line before being attenuated down to oblivion.  And I'm distracted by the (obvious) point that 2.4GHz interference would be expected to knock out the WiFi connections rather than the DSL connections, yet it seems to be the DSL connections that are getting killed.

So, I'd be inclined to suspect that the interference is (1) at a much lower frequency because it knocks out the DSL, and (2) that it is rich in harmonics, as it seems to be seen in GHz bands too, and also in TV (UHF) frequencies.   For example, a pure square waveform is actually the sum of an infinite series of harmonics (since 'infinity' is difficult, that's why there's no such thing a a 'pure' squarewave).

Most interesting of all, perhaps, is the suggestion that it occurs at the same time every day.  Do we know if there's any big electronics installations in the nearby countryside?  Military, for example?  Or a hospital?  And if so, do they by any chance make a habit of restarting some of their toys every day when the afternoon shift signs on?

- 7LM

[waltergmw]

Hi 7LM,

Indeed there's a lot of military as they are on / near Salisbury plain.
They have a firm up the road that plays around with electronic countermeasures and have not been successful with any enquiries there - I wonder why !

Whatever is the cause seems to radiate massive amounts of energy as very similar effects have been observed on ADSL circuits in the adjacent exchange.

I also agree re the harmonics.

Many thanks and kind regards,
Walter

[general disquiet]

Thanks for raising this walter and for the suggestions - all very useful, as any new angles are always welcome.   Many of the questions you raise are answered in the various postings on the blog, but rather than inflict that on you, I'll summarise.

The REIN hits at between 0130 and 0330 every day and the time shifts appear to be on a 6 day cycle.  I usually avoid this one by using a timer to switch the router off.  The second REIN spike happens at around 1348 +/- 1 minute and nearly always on weekdays, less often on Fridays than other days, rarely at weekends and often when it is wet - drizzle being worse than torrential rain.  The BT REIN engineer who visited last year reckoned there were two other minor events midway between the two already mentioned, but not big enough to cause routers to lose sync.  So, they happen nearly every six hours

The village lies at the junction of a wooded valley running N/S and an open valley defined by the A303 running E/W.  As a consequence it is in a terrestrial and digital radio, tv, satellite and mobile phone dead spot with poor reception for all of these.

I agree with 7LM's view.  The signal I picked up on the Wi-Spy spectrum analyser isn't a 2.4 GHz signal, it just happened to be picked up by the spectrum analyser.   I dare say if I'd got access to one with a wider frequency range, it would have picked up some sort of signal across the complete frequency range.

The local military bases and QinetiQ lab that play with radio and radar are adamant that they have no kit that would cause this type of effect.

Incidentally, although the signal in the 2.4GHz band is visible, its relatively low intensity and I rarely have problems with wifi and none that I can ascribe to the REIN.

[jeffbb]

Hi
quote : the second REIN spike happens at around 1348 +/- 1 minute and nearly always on weekdays, less often on Fridays than other days, rarely at weekends and often when it is wet - drizzle being worse than torrential rain.

 often when it is wet - drizzle being worse than torrential rain this bit is perhaps a pointer .

this would suggest that whatever it is is exposed to the weather

If some electrical appliance was actually switched on and had a faulty insulation then when dry would cause some arcking
when soaking wet reduced as the water (not pure ) would act as a conductor for some of the current reducing arcking
when damp  would reduce the insulation properties so create more arcking


As the whole village is affected then maybe the rein is generated near the exchange or at least close to a point where the telephone cables are closely packed , and not necessarily close to  to the individuals affected .

Regards Jeff

[general disquiet]

There are a couple of people who are unaffected.  One of them is at the point on the overhead cable furthest from the SCP, the others are randomly scattered throughout the village - there seems to be no common denominator that marks them out as different.

I've followed every inch of the (underground) cable from the SCP in my village to the PCP in the next and can find nothing that might operate so regularly within 400m either side of it.   Electric fences, ye - and they were causing some problems, but they work 24/7.

I think is is possibly electrical equipment in someone's home, but every time we think get a lead, it turns out not to be. 

[waltergmw]

@ The general,

How about checking the Upavon line as well with your Wi-Spy ?

If you were allowed to install a laptop with Routerstats running as well as the Wi-Spy you could then access it remotely via a Logmein account and compare the results of several incidents.

It's almost certain that you have a common source producing these effects so I'd guess the source is in line of site of both your Winterbourne Stoke properties and the one off the Upavon exchange.

You could also chat up the Shrewton folk to see if they too are affected ?

Another plan would be to examine the Winterbourne Stoke properties that do and don't have the problem. Are any of them in the shaddow of another building etc. ?

Kind regards,
Walter

[general disquiet]

@Walter,

Lots of good ideas and I may give some of them a try - my big problem is lack of time!  I'm hoping to get the Wi-Spy used in a different part of the village during the week, so we will see how things go.

Shrewton don't have the problem, but then again most are on v good quality copper with IP profiles >6Mbps

As for Upavon, well, we thought we had a line of site issue a few moths back, but the last I heard, thei problems seem to have resolved, so it may have just been a coincidence. 

No common features between those who are afflicted and the minority who aren't.  One of the best connections is in the middle of a row of 6 originally identical properties with the adjacent property having one of the slowest connections.

[sevenlayermuddle]

One more though occurred to me.  You mentioned interference on a neighbour's TV.  Was that on an analogue channel. or digital?

The reason I ask is that the pattern on an analogue TV screen gives some strong hints as to the type of interference.  There's no hard rules, but I'd suggest that in many cases random dots flashing across the screen can suggest something's arcing, like a poorly made switch contact.  The same, but a more regular pattern, suggests something like a badly suppressed motor commutator, or sometimes electronic switching equipment (in that case there may be a pattern that is constantly changing).  Swirly wavy lines suggest a badly behaved radio (or similar) transmitter.

- 7LM

[general disquiet]

As far as I am aware (but will check) it is an analogue TV and it showed a brief pattern of dots towards the top of the screen - at the same time, the owner loses his broadband connection as the router resyncs.  The other odd (?) thing is that the interference is NOT recorded on a video recorder.  Not sure if that means anything though.

[sevenlayermuddle]

towards the top of the screen

A pattern aligns itself vertically in the picture may be related to the TV's vertical scan frequency of 50Hz, which is also of course the mains supply frequency.  That's actually why 50Hz was chosen for TV scan frequency, as static distortion is usually less anoying than moving distortion.  I'm not really sure where to go with that idea from here, however, other than to ponder whether any mains supply equipment could spring to life at the times of day you've noted? 

Alternatively, all analogue TV broadcasts these days include dot patterns in the first few scan lines of the screen.  They carry the teletext data, and are normally invisible on a properly adjusted TV.  Perhaps the interference signal is causing the TV to lose sync a little bit, and to show these lines?  Sometimes boadcasters screw up and show dot patterns that govern things like aspect ratio, but that's usually obvious as a broadcast defect, and doesn't look like interference.

If you think the TV interference is representative of the problem, I wonder if it's maybe worth posting on some amateur radio forums that could give a more concise analysis?  I'm not a radio HAM myself, so can't recommend any forum but I feel sure they must exist.

Good luck!

- 7LM

[sevenlayermuddle]

mains supply equipment could spring to life at the times of day you've noted? 

PS:   Sorry, one more thought occured...  Any chance it's related to a backup generator?  I see that as well as the military, there's a small private hospital at Winterbourne.  I'd have thought either the miltary or the hospital or both may have they're own generators, and they may well test them regularly, perhaps even at the same time every day?

Playing devil's advocate to that suggestion, I can't see them being tested more than once a day, and I think the problem arises several times daily.  Still, any inspiration...

[waltergmw]

Hi General:-

Just to add a couple more thoughts to 7LM's ideas:-

If there is a "mission critical" device with inbuilt dual redundancy some systems employ auto-change-over logic to test the readiness of the standby unit.

Other devices with auto-switchover capabilities might include clean and dirty water treatment systems some of which have e.g.

dual filter beds with auto-cleaning cycles
timed water pumping units to fill or empty reservoir tanks

However how these might change over a weekend is still yet another puzzle,
unless they are supplying a manufacturing process only.

Kind regards,
Walter

[general disquiet]

Hi Walter,

We've looked at all the (well the few) industrial/agricultural processes along the backhaul.  We even persuaded the local authority to turn of a small sewage works overnight just in case that was it.  Absolutely nothing found.

[waltergmw]

@ The General.

That's very disappointing  so I suppose you are back to more Wi-Spy observations.

Another thought I had was that QinetiQ are not going to be over-enthusiastic in announcing what they're up to.

How about taking your Wi-Spi and a laptop and parking at a discreet distance but close to their establishment ?

Kind regards,
Walter