Heat related dropouts?

I live approximately 300m from the cabinet. From there, ancient copper wiring travels a short distance underground. Then it goes overhead and hops from pole to pole, before diving underground again. My master socket is in an upstairs bedroom.

In recent years, I have suffered intermittent problems with my FTTC broadband service, with a history of dropouts and declining speeds. So following advice from these forums, I drilled a hole through the wall from the master socket in the bedroom into my home office. Then, I fed a short length of Cat 5e cable through the wall and installed an RJ45 socket, next to my router.

A former BT engineer has checked the wiring and installed a new Openreach 5C master socket and Openreach Mk 4 faceplate. So now, the router has a direct connection to the master socket and all of the telephone extensions have been separated and run from the filtered back of the faceplate.

I used to achieve download speeds of between 50 and 52 Mbps, which is probably as good as the line will support. But last week, DLM started to adjust the line profile and reduced my download speeds significantly. Consequently, I reported a fault to BT.

An Openreach engineer attended on Monday morning. The recent heatwave had started, but he arrived before it had become became too hot. The engineer checked the external wiring between the cabinet and the master socket and found no faults. However, he mentioned the probability of electrical interference and crosstalk in the wires from the master socket to the DECT telephone base station and various extension sockets. I was under the impression that the filtered Openreach socket was supposed to reduce or eliminate crosstalk and electrical interference, so I don’t know whether that is likely.

Finally, the Openreach engineer raised the line profile to 58.74 Mbps fastpath (DLM seems to have reduced the profile subsequently to 54.45 Mbps).

Following the engineer's visit, I have been plagued by frequent dropouts, so every afternoon, my Internet connection has become unusable. But then, from around 5 pm until noon on the following day, there have been no dropouts. I have analysed the router logs, which confirm that dropouts have continued for four or five hours, but have only occurred during the afternoon. At other times, the line has remained stable.

This is what has happened this week:

Mon, 19 July 16:26 until Tue, 20 July 12:07 - Stable for 19h 40m
Tue, 20 July 12:07 until Tue, 20 July 17:16 - 21 dropouts within 5h:09m
Tue, 20 July 17:16 until Wed, 21 July 12:51 - Stable for 19h:35m
Wed, 21 July 12:51 until Wed, 21 July 17:15 - 25 dropouts within 4h:24m
Wed, 21 July 17:15 until Thu, 22 July 11:50 - Stable for 18h:35m
Thu, 22 July 11:50 until Thu, 22 July 16:19 - 28 dropouts within 4h:29m
Thu, 22 July 16:19 until Fri, 23 July - Still working OK at 18:00

This is a list of my router settings and current statistics.

Product name: BT Hub 6A
Serial number: +084316+NQ6415*****
Firmware version: SG4B1000E020
Firmware updated: 20-Mar-2020
Board version: 1.0
Gui version: 1.115.0
DSL uptime: 1 Days, 0 Hours 19 Minutes 19 Seconds
Data rate: 12.67 Mbps / 56.25 Mbps
Maximum data rate: 12825 / 70636
Noise margin: 8.4 dB / 7.1 dB
Line attenuation: 23.6 dB
Signal attenuation: 15.3 dB / 23.6 dB
VPI / VCI: 0/38
Modulation: G_993_2_ANNEX_B
Latency type: Fast Path

The results of my latest TBB speed test are at www.thinkbroadband.com/speedtest/1627056456478852555.

The BT wholesale speed tester has reported: Latency 29 Ms;
The Download speed achieved during the test was 51.17 Mbps.
For my connection, BT say the acceptable range of speeds is 40 - 54.45 Mbps. The IP Profile for my line is 54.45 Mbps
Upload speed achieved during the test was 11.82 Mbps. The IP Profile for my line is 20 Mbps.
All of these appear to be satisfactory.

We do not use any electrical equipment in the house that might have caused the recent problems. Furthermore, dropouts were occurring around the same time every day and coincided with the very high afternoon temperatures. I have considered the following possible causes:

Could the very high temperatures have affected the overhead sections of the Openreach wiring, between the cabinet and the house?
Electrical interference in the locality
Could the high temperatures have affected my extension wiring?

I have one particular concern. The telephone wiring from the master socket runs outdoors, up the side of the house and into the loft, where there is a junction box. From the junction box, one wire goes to the telephone base station and another wire goes to the extension socket in a room, with a Sky receiver.

The external brick wall has felt very warm this week. Those wires have been there since we bought the house in 1984 and the insulation might have deteriorated.

It would be intolerable, if I could not use the Internet, every time we experience sub-tropical temperatures. Consequently, I would greatly appreciate any suggestions and advice about what I should do next.

The high temperatures play havoc with many DSLAM cabinets, particularly if they are in direct sunlight. ECI cabinets are especially prone to overheating problems , contamination of the cards and line card failures. Your symptoms have many hall marks of being a DSLAM related issue.

Virgin Media is not immune, as when the sun is extremely strong as we have had this week, the expansion of the metal work in my local cabinet causes the coax connections to fail and the cable modem to disconnect. (Luckily I don't use them for TV, or I would be more than annoyed). Usually its back within 20 minutes, but yesterday was so hot that it was nearly 2 hours of outage.

I hope pure-FTTP will solve this by having (almost) no active components in the street.

For your situation, perhaps a cellular backup on 4G/5G ?

Edited by jchamier (Fri 23-Jul-21 19:54:19)

The simplest explanation used to be the modem/router itself over-heating. Particularly if on a window-ledge or a table where the sunlight hits it. I used to suffer from it a lot, until I got wise to it and took precautions to shade it/them on hot summer days.

The last few days have been ridiculous temperatures throughout the house of course, but the roller blind in the room my (Home Mobile Broadband Router) sits has not been rolled up for days. The most susceptible to heat was the old Openreach HG612 modems LOL. They could overheat from two people being in the room on a rainy day.
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OK, that's an exaggeration .

In reply to a post by witchunt:

The high temperatures play havoc with many DSLAM cabinets, particularly if they are in direct sunlight. ECI cabinets are especially prone to overheating problems , contamination of the cards and line card failures. Your symptoms have many hall marks of being a DSLAM related issue.

Thank you for putting my mind at rest. I was dreading the prospect of having to replace all of the old extension wiring. Was I correct, when I thought a filtered master socket should remove the possibility that extension telephone wiring could affect the speed and stability of my Internet connection?

It feels decidedly chilly now - and the Internet connection is still up and running.

In reply to a post by pluralist:

The most susceptible to heat was the old Openreach HG612 modems LOL. They could overheat from two people being in the room on a rainy day.

How dare you sir! I'll not accept any criticism of the HG612. Mine might be old but it's still going strong and doesn't seem bothered by the heat either from the room or that wafting up from the computer below it.

I have every intention of continuing to use it right up until I get an ONT in (hopefully) a couple of years.

Yes, we all know about yours .

I can only conclude it was one of a batch of ten hand-built from top grade components anywhere in the world except China as proof that the first proof of concept lab one wasn't a fluke, or maybe such a Chinese one with UK peering site spyware built-in slipped into a normal batch for Openreach.

😎😈😈

In reply to a post by jchamier:

For your situation, perhaps a cellular backup on 4G/5G ?

Unfortunately, a cellular backup would not be a viable option. The signal to my home is very weak, so I am glad my cellphone is compatible with Wi-Fi calling. Otherwise, it would be difficult for me to make or receive mobile calls.

Bob_lucas

Heat will affect all the active components and each may cause your problems. Wiring is less likely until it fails completely.

Active will include the DSLAM, Modem, Router, (Switch) and end devices.

Most likely, for you, is the DSLAM ( As per Witchunts post) or Modem/router. Make sure yours in in a cool place and/or well shaded.

My Partners computer is in the top of the house and requires a Fan aimed at it during hot weather to keep its speed up to a reasonable level. This moves the air through the internal fan much ,more effectively. The modem is nicely shaded and works sweetly

We used to joke that the first works laptops we had, needed to be stood on matchboxes to get air flow underneath or they slowed to a stop. ( Leave the matches in to get a newer model! )

In reply to a post by kitcat:

Bob_lucas

Heat will affect all the active components and each may cause your problems. Wiring is less likely until it fails completely.

Active will include the DSLAM, Modem, Router, (Switch) and end devices.

Most likely, for you, is the DSLAM ( As per Witchunts post) or Modem/router. Make sure yours in in a cool place and/or well shaded.

Thank you.

Yesterday was much cooler and my connection remained stable for 34 hours, with no dropouts whatsoever. DLM responded overnight by resetting the profile to 65/20 (previously 58/20). The profile has never been so high, so 65 that might be too optimistic. We shall see because unfortunately, dropouts have resumed today at 1 pm.

It still think the problem is caused or aggravated by excessive heat but unfortunately, we don't know which components are affected. It is slightly warmer today, but not stiflingly. Furthermore, the curtain in my office is closed. A thermometer by the modem/router reads 21 degrees so I suspect the problem is in the DSLAM or in one of the cable joints between the cabinet and my home.