Print

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

[jack21]

I've been investigating the source of sporadic, intermittent high CRC rates on my broadband since 2008......I mean I've spent 6 years investigating!! They come and go, can be disruptive in that DLM may raise the SNRM, increase interleaving depth, or even 'cap' the line.

Over the years I've eliminated in-house sources, near-neighbours premises, factory, farms, turbines, radar etc......but in the last week, especially the last 2 days due to a weather radar site pointed out to me by Forum Member NewtronStar,  I've been able to accurately pinpoint the source.......it is weather!!!

I've determined that, for my line, any atmospheric disturbance over a certain level will cause the CRCs to shoot up to higher levels - sometimes from 0 to 20, 0 to 60 or even 0 to 1000 (examples).....the key point being that the disturbance can be 100+ miles away and have no visible signs locally, and yet still affect my line CRCs. The disturbance occurs when lightning is happening, or even before lightning happens, while the electric charges are escalating in cloud systems before reaching a lightning threshold. If the disturbance is closer, say 40miles, then the SNRM is also affected, and visible bad-weather signs in the sky can be seen. When a disturbance is local, within full view, that's when the SNRM violently dips and CRCs can soar to 1000's per minute. Using the weather radar site, I can now predict if/when a disturbance is going to affect me.

I think that because my line is so long....5km....and attenuation so high (69db for most of the time)......that my line is particularly prone, and that people whose lines are shorter may not be so affected.

Even though I can't do much about it, I feel much relieved that the cause has been found, and that I can stop feeling suspicious about neighbours' electrical activities!
And at least I could turn my modem off when a particularly bad spell is predicted!

[Black Sheep]

Great feedback Jack. 

[jack21]

Thanks BlackSheep; I'm feeling especially grateful to Openreach - most especially to a local (Scarborough) one who recently decisively replaced the E and part of the D side of my then problematic line (particularly problematic after moving to 21CN) and achieved an attenuation of 59db (was 69db) and corresponding significant higher sync rate!

[Black Sheep]

That's good to hear about your lower attenuation. Barring a major 'HR' fault on the D-side, I would imagine that kind of 10dB gain, was obtained from moving you onto a better E-side cable from Exchange to Cab ?.

I think you are the second individual now to comment on weather patterns (Thanks to NS for that brilliant link - Its now one of my 'Favourites') being the cause of the high CRC/ES counts ??.
It goes some way to show that it's not always down to Openreach's MPF, and I'm sure more Kitizens, will use the NS link to try and tie-in events before maybe heading down the route of raising an SFI Engineering visit ?? 

[jack21]

@BlackSheep

The E-side is around 4Km to Cab1 in village 1 and everyone I've helped who are on Cab1 have attenuations around 55db.....but then there's another 400m to Cab2 in village 1, and that stretch seems to suffer the most HR faults. Attenuations  for village 1 users I've helped on that cab2 are from 58 to 64db, but there is one road where all are around 65db. Then there's another 400m to village 2 (where I live) and attenuations there range from 57db to 69db......so I had the worst in village 2 and now there is only one lower than mine!

The OR engineer was exceptionally involved and helpful; he looked at my stats records, did line tests aplenty and even allowed me to contribute towards picking a replacement pair. The weather was absolutely foul - freezing and pouring rain, and I was happy to take a pair from the exchange thru to Cab2.....then use my existing final 400m. And he wouldn't stay for fish and chips because he was running late for his next appointment! - dedication!

We may be getting FTTC to Cab 1 in due course, courtesy of an East Riding Council initiative.......happy days!

[Black Sheep]

I'm pleased you've had what we would term a, 'Happy Customer Experience'. We only tend to read about the the bad ones on forums, as is human nature.

I am however, slightly confused as to the Cab set-up in your village/s ?? Not that it's hard to confuse me these days, but I've read your post three times now and can't work out if there's a Cab 3 in your village (Village 2), or you are fed from Cab 1 or Cab 2 from Village 1 ??
I'm also curious as to whether there is actually just one Cab (Cab 1), and the others are what we call SCP's (Secondary Connection Point) ??

You seem happy that Cab 1 is going to be made FTTC active, so I'm guessing that the others are indeed SCP's ?? 

[jack21]

Ah, sorry - my blissful glow is making me careless!
Cab 1 in village 1 is where FTTC would be based - 'my' OR chap told me that........then there is cabling from Cab 1 to Cab 2 (in village 1) and Cab 2 won't have any FTTC kit inside/nearby. I don't know what Cab 2 is termed, but everyone on that side of village 1,plus everyone in village 2 are (as far as I know) connected to that Cab 2........there is no Cab 3.

[Black Sheep]

Aha, that's better ….. thank you. 

Then, you have to hope that what you refer to as 'Cab 2' is in fact a SCP ?? If it isn't, then you won't get FTTC when 'Cab 1' is made active ?

I suspect from your wording ("There is cabling from 'Cab 1' to 'Cab 2') that it is a SCP, and not a stand-alone 'Cab'. I hope this doesn't sound too pedantic, but the wording is all-important here …… it's the difference between getting FTTC or not ?? 

[jack21]

I'm sure you're correct, BS, SCP2 it will be ever thus! I recall 'my' chap advising me that the total distance that would be from home to Cab1 was very close to a borderline distance for FTTC to be available, and that I should place any order via internet rather than by voice to avoid any unlikely possibility of being distance-rejected.....does that make sense?

[kitz]

Just adding in my 2p.

Ive been aware for many years that thunderstorms are one of the few things that affected my own line.  Im on a pretty short run of (UG) copper yet even I can see the effects of an electrical storm many miles away and not particularly close to the exchange or my house.  Basically if you hear a rumble then it could trigger the CRCs.   I think I first observed this either when I was on 2Mb or maybe maxdsl because I can recall the make of router in use at the time as I sat one night watching the CRCs clock up during a storm... so this must have been a good 8+ yrs ago as it was when I used the Voyager 2100.

Under normal conditions that line would NEVER produce any CRCs aside from about  a couple during sync, then it would stay like that for weeks/months - aside from storms - so I should imagine they could affect longer lines a lot more.

Now Im on VDSL its a wee bit more temperamental.

[konrado5]

m on a pretty short run of (UG) copper yet even I can see the effects of an electrical storm many miles away and not particularly close to the exchange or my house.

What is cause? Is electrical interference get under the ground?

Best regards
konrado5

[4candles]

A lightning strike is akin to a short duration, but extremely powerful, spark transmitter. It gets everywhere!

[JGO]

4candles

"A lightning strike is akin to a short duration, but extremely powerful, spark transmitter. It gets everywhere ! "

Yes, not only as a radio impulse but also as earth currents as the strike dissipates.

[kitz]

AIUI, whilst UG cables may not be a direct target for a lightning strike, they too suffer the affects from storms.  Thunderstorms can build up a mix of static electricity, EMI and RFI.   RFI can traverse through solid objects (just like how walls dont stop radio signals) and therefore can cause noise on UG cables too.  RFI from storms can often be heard on AM frequencies.

EMI from lightning produces a broad range of impulse type noise over various frequencies and can affect all types of telecommunications.  The generation of EMI noise impacts the on the SNR by reducing any margin.   This in turn causes CRCs and Err Seconds etc.

[konrado5]

EMI from lightning produces a broad range of impulse type noise over various frequencies and can affect all types of telecommunications.  The generation of EMI noise impacts the on the SNR by reducing any margin.   This in turn causes CRCs and Err Seconds etc.

At the time of thunderstorm my SNR margin raises and not lowers. Yesterday I had thunderstorm and my SNR margin raised from 1.6 dB to 2.0 dB, and subsequently to 2.8 dB.