Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[general disquiet]

@ Ezzer and waltergmw

I finally tracked down a useful document with some very specific advice on tracking down RFI.  It builds on the information the Ezzer gave on the use of a ferrite aerial for DF-ing purposes and it has some interesting bits on detecting ground transmissions.

http://www.rsgb.org/emc/pdfs/leaflets/emc4interferencetoamateurreceptionmembers.pdf

I hope it is of some use to others.

[roseway]

That's a very interesting document. Thanks for finding it.

[waltergmw]

@ general,

Indeed a very useful document produced by people who need to know about these things.

I'm still as puzzled as ever by your noise spike problem.
As it appears to be a weekday single spike at differing, but regular, times of the day it must surlely be some sort of commercial or military plant.
Being a "single" spike it could be caused by starting or stopping plant, but if that were so you might expect a "double spike" i.e. stop for rest break and restart afterwards.
That suggests it's only the stopping OR the starting activity which produces the serious effect. If you can detect the frequency then you might observe much lower magnitude signals at other times. Could there be any plant using regenerative breaking - although that might be expected to continue for a long period ? Could there be any plant using high voltage AC or DC circuit breakers with faulty arc suppression equipment? Could there still be an old mercury arc rectifier or similar being used somewhere ? Could there be an 33 Kv to 11 Kv auto tap changer causing the problem - unlikely as it's only during week days unless it's only a heavy commercial load causing a particular tap to be be used ? Perhaps taking your radio to the local bulk supply points might show something ?

If it is not an industrial process perhaps another avenue might be to check on some form of military test transmission used to test the effectiveness of devices used to filter or isolate noise transmissions. Chatting up the military and their contractors would seem like a good idea if only they can be persuaded to co-operate.

In any event it does seem necessary to record and then analyse the frequency and the duration of the spike over all the regular transmission periods observed.

Expanding one of my earlier thoughts, if you were to draw two circles on the intercept line between your villages; one centred half way along the line the other offset by the difference in signal size it would describe an envelope for further investigation. You probably then need to contact every village and hamlet within the area and possibly those near to it to observe their ADSL performance.

To recap on the known information re Enford and you, it suggests a high power device capable of causing similar effects on different ADSL lines in two different villages 12.5 km apart served by two different telephone exchanges. I'm guessing that it is improbable that the spike is either caused by or reflected from one exchange to the other. That could be investigated if BT's REIN engineers could observe and record the spike at the exchange end on the lines known to suffer. They could also observe other ADSL lines in the two exchanges and any others closeby.

Let's hope some others here can come up with more ideas.

Kind regards,
Walter

[general disquiet]

Just to clarify a little.  There are 4 REIN spikes a day (at least that is what the BT REIN specialists reckoned) which occur at roughly 6 hour intervals.  Of these, the one at 0130 (+/- 2hours) happens every night, regardless of weather and cause routers across the village to lose sync.   

The REIN at 1350 (+/- 2 hours) also causes routers to lose sync, but tends only to occur Monday to Thursday and is rare on Fridays, weekends or Bank Holidays - which fits with some sort of commercial activity, but not with the military.

The other two REIN spikes are rarely seen and equally rarely cause a loss of sync and then only in extremely bad weather.

We have found one TV in the village that shows interference when the 1350 REIN spike hits and at the same time the owners router loses sync - the info from the RSGB indicates that we might be able to use this as grounds to get Ofcom to investigate.

[orainsear]

You mentioned previously that the timing of the pulses tends to drift.  Is there any pattern to the drift?

[general disquiet]

The timings of the pulses are on a 6-day cycle.  Here is some data from a while ago when I was still recording every day!



I've never had enough time to record (manually) all 4 REIN peaks every day!

[orainsear]

If the timing of the pulse was a bit more regular I was thinking it may have been something like a weather radar, although I suppose it is still conceivable that something like that could be causing the pulse.

Picking up on Walters points, is there anything 'industrial' going on in the area where they could be working to shift patterns?

[general disquiet]

Salibury Plain training area to the north, Boscombe Down to the north so loads of military and civilian radar and radio - but they tend to operate all day, every day.  All, unsurprisingly, deny it could be them.  Other than that, no industry other than farming.  Half the farms in the area are also affected, so have a vested interest in finding the source.

[general disquiet]

I managed almost a whole week with no sign of REIN and a raised IP profile of 1500 kbps.  I even got hopeful that I might see a drop in the SNR target.   It wasn't to be.  Heavy rain yesterday and the IP profile has dropped to 1250kbps. Grrr!

[general disquiet]

Things going from bad to worse.    For once, we suffered a loss of sync on a Friday lunchtime.   Detailed log from the 2-Wire looks as follows:  Grateful for any ideas!

INF       2009-09-04T13:44:45+01:00      lmd:  dsl0: down (signal lost)
WRN    2009-09-04T13:44:45+01:00    lmd:  qos0: admin_gen: unable to lookup clfy netdev pvc0: No such file or directory
WRN    2009-09-04T13:44:45+01:00    lmd:  Previous log entry repeated 31 times
WRN    2009-09-04T13:44:46+01:00    vrsip:  Broadband connection lost
INF    2009-09-04T13:45:04+01:00    lmd:  dsl0: up G.DMT Annex A interleaved Rate:864/448 Max:864/516
INF    2009-09-04T13:45:04+01:00    lmd:  dsl0: Margin:12.0/9.0 Atten:63.0/31.5 Power:15.1/12.3
INF    2009-09-04T13:45:04+01:00    lmd:  dsl0: Country: {B5} Vendor: {TSTC} Specific: {0}
WRN    2009-09-04T13:45:04+01:00    lmd:  qos0: admin_gen: unable to lookup clfy netdev pvc0: No such file or directory
WRN    2009-09-04T13:45:04+01:00    lmd:  Previous log entry repeated 31 times
INF    2009-09-04T13:45:05+01:00    voiced:  Set 0 IP to 519b:7cc2:600:0:100::
INF    2009-09-04T13:45:05+01:00    voiced:  reset port 0
INF    2009-09-04T13:45:05+01:00    voiced:  Set 1 IP to 519b:7cc2:600::100:0:2400:0
INF    2009-09-04T13:45:05+01:00    voiced:  reset port 1
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceDestroy()
ERR    2009-09-04T13:45:05+01:00    sip:  SipProcessMsgs(): NULL hcall
INF    2009-09-04T13:45:05+01:00    vrsip:  port 0: voice on broadband 21
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetLocalIP() - 519b7cc2, 81.***.***.*** [IP deleted]
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetLocalPort() - Local Port #:5070
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetRemoteIP() - sp2.btsip.bt.net
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetRemotePort() - Remote Port:5060
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetDomainName() - btsip.bt.com
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetQos() - QOS:type 0, value 2
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetQos() - QOS:type 2, value 46
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetQos() - QOS:type 1, value 6
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetQos() - QOS:type 3, value -1
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetTransProt - inst uses UDP as default
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceSetNtwkCallFeature() - 41814010 0
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceStart() - local IP: 519b7cc2 81.***.***.*** [IP deleted]
INF    2009-09-04T13:45:05+01:00    sip:  SipInstanceDestroy()
ERR    2009-09-04T13:45:05+01:00    sip:  SipProcessMsgs(): NULL hcall
INF    2009-09-04T13:45:06+01:00    vrsip:  port 1: voice on broadband 21
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetLocalIP() - 519b7cc2, 81.***.***.*** [IP deleted]
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetLocalPort() - Local Port #:5071
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetRemoteIP() - sp2.btsip.bt.net
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetRemotePort() - Remote Port:5060
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetDomainName() - btsip.bt.com
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetQos() - QOS:type 0, value 2
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetQos() - QOS:type 2, value 46
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetQos() - QOS:type 1, value 6
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetQos() - QOS:type 3, value -1
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetTransProt - inst uses UDP as default
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceSetNtwkCallFeature() - 41820c10 0
INF    2009-09-04T13:45:06+01:00    sip:  SipInstanceStart() - local IP: 519b7cc2 81.***.***.*** [IP deleted]
INF    2009-09-04T14:34:05+01:00    cwmd:  retried session started, server: 'https://pbthdm.bt.motive.com/cwmpWeb/CPEMgt', event code(s): '4 VALUE CHANGE,1 BOOT'
WRN    2009-09-04T14:34:07+01:00    cwmd:  authentication has already been tried once and we still don't get in
WRN    2009-09-04T14:34:07+01:00    cwmd:  session failed...
INF    2009-09-04T14:34:07+01:00    cwmd:  session will be retried in 2698276(ms)
INF    2009-09-04T15:19:35+01:00    cwmd:  retried session started, server: 'https://pbthdm.bt.motive.com/cwmpWeb/CPEMgt', event code(s): '4 VALUE CHANGE,1 BOOT'
WRN    2009-09-04T15:19:38+01:00    cwmd:  authentication has already been tried once and we still don't get in
WRN    2009-09-04T15:19:38+01:00    cwmd:  session failed...
INF    2009-09-04T15:19:38+01:00    cwmd:  session will be retried in 2510146(ms)
INF    2009-09-04T16:01:36+01:00    cwmd:  retried session started, server: 'https://pbthdm.bt.motive.com/cwmpWeb/CPEMgt', event code(s): '4 VALUE CHANGE,1 BOOT'
WRN    2009-09-04T16:01:38+01:00    cwmd:  authentication has already been tried once and we still don't get in
WRN    2009-09-04T16:01:38+01:00    cwmd:  session failed...
INF    2009-09-04T16:01:38+01:00    cwmd:  session will be retried in 2771509(ms)
INF    2009-09-04T16:21:36+01:00    lmd:  device0: dsl0 has no current version set
WRN    2009-09-04T16:21:36+01:00    lmd:  qos0: admin_gen: unable to lookup clfy netdev pvc0: No such file or directory
WRN    2009-09-04T16:21:37+01:00    lmd:  Previous log entry repeated 15 times
INF    2009-09-04T16:21:37+01:00    lmd:  device0: dsl0 has no current version set
WRN    2009-09-04T16:21:37+01:00    lmd:  qos0: admin_gen: unable to lookup clfy netdev pvc0: No such file or directory
WRN    2009-09-04T16:21:38+01:00    lmd:  Previous log entry repeated 15 times
WRN    2009-09-04T16:36:52+01:00    named:  resp recvfrom 194.74.65.68 errno=49

[orainsear]

Perhaps it was one of the interference pulses that took the connection down.

>>>>G.DMT Annex A interleaved Rate:864/448 Max:864/516

If the router has been synced at that rate since this afternoon the profile has probably dropped to 750 kbps   

[general disquiet]

Yep, you are spot on, sad to say:

Test1 comprises of Best Effort Test:  -provides background information.
    Your DSL connection rate: 864 kbps(DOWN-STREAM),  448 kbps(UP-STREAM)
    IP profile for your line is - 750 kbps
    Actual IP throughput achieved during the test was - 689 kbps