Broadband speed dropping , not reliable

[#1]

Our broadband speed has been terrible over the last 2 x weeks.
BT never upgraded our network so stuck with poor infrastructure.
Was getting 21 Meg but lately dropping to 7 - 12 Meg.
Checked Noise margin = 18.3 ? Which is high !
Took picture of tech page info

[#2]

First thing to check: Is your phoneline clear? Dial 17070 (preferably from a corded phone), select option 2. Once your phone number is confirmed, there should be silence on the line except for the regular 'Quiet Line Test' message - any other noise, report a PHONE problem via: https://www.plus.net/help/report-a-problem/phone/

If the phone test passes, report a broadband problem via: https://www.plus.net/help/report-a-problem/broadband/

Let us know the result - if the tests come back as clear but you still have a problem, we need to investigate further.

The above assumes you still have 'normal' landline connection - if you have a SOGEA (internet only) one the only option is to call Plusnet - 0330 123 9123

[#3]

Hi ,
Did all this last Friday and was instructed to switch off hub as they were unable to “Refresh” remotely.
When doing the 17070 quiet line Test, I am getting a Telephone exchange background buzzing noise on the line.
Again, shouldn’t the noise margin be down to around 6db unlike what I getting 18.3 on hub ?
Philip

[#4]

The line should be totally silent on a QLT. It is a bit late, but if you can follow the script below, I'll have a look early tomorrow morning. Yes, your noise margin is high, but without further information, it is difficult to know exactly what is causing it, or what suggestions to make.

For Community members to be able to help, information from these sites, as screenshots, posted as pictures within the topic, not as attachments:-

BT Broadband Availability Checker (obscuring your phone number), where a landline phone is no longer supplied or known use the address version BT Broadband Address Availability (obscuring your address)

BTW Performance Tester - Over a wired (Ethernet) connection if at all possible, please report the 'ADDITIONAL DIAGNOSTICS'. This test is recommended to be performed with only one device connected.

Sight of the broadband connection status from your Hub (with the 'Username' obscured) would also be of help.

For the Hub One -

Navigate from the Home Screen to Troubleshooting > Helpdesk

For the Hub Two -

Navigate from the Home Screen to Advanced Settings > Technical Log > Information

Where the phone line is still active, it may also be a good idea to report the results of a Quiet Line Test - dial 17070 option 2 from a (preferably corded) phone. After the confirmation of your phone number, there should be total silence apart from the regular 'Quiet Line Test' announcement. Any other noise - report a PHONE fault first.

If you are unsure about any of the above, please just ask - I am happy to help.

[#5]

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@PhilipT15 wrote:
..... shouldn’t the noise margin be down to around 6db unlike what I getting 18.3 on hub ?

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There might be a simple explanation for your slow speed that will come to light if you post the information requested by @jab1. Regarding this particular part of your question there ar two possible scenarios.

1. You have had problems in the past and your line is banded. Data requested above might identify this.

2. The geek in me puts forward this theory:

The quiet line test only reveals noise on the line in the audio band. If there is noise present it is indicative that there will also be noise at the higher frequencies used by the broadband tones. If this noise was of uniform amplitude across the entire band then I too would expect the SNR to settle at 6dB, but at a lower speed. However, wide band noise is unlikely to be uniform, with 'spikes' in amplitude popping up at random frequencies. These will result in the error count rising to the level that triggers the DLM, which will automatically increase the SNR in order to bring down the error count and so reduce the need to retransmit data to an acceptable level.