"12 and a bit down today, but only .62 up." -- I doubt that would be too terrible.
Plusnet support had a good reputation before the BT takeover - try a call.
Get the line tested. Not sure if you will be allowed to use the BT Customers automatic line test. GOD! you need a login now. Try it anyway.
Test the phone. Use a plain old phone if at all possible.
Listen for noise (crackles). Get someone else to do the same on the other side.
If there are phone issues get the phone fixed without mentioning broadband problems. They have to fix the phone, broadband is optional. You likely agreed to a Service level of none.
Get Pingplotter an ping bbc.co.uk, google.co.uk, 8.8.8.8
Look for drops in the various hops. Leave ping plotter running all of the time so that you can look at the history if you experience service problems.
Use the Master Socket (has a split faceplate) to eliminate internal wiring issue/interference from other phone-line-connected equipment. Take off the lower faceplate and plug-in inside. Disconnect the filter if you can (you need a suitable rj11-BT cable) since it won't do anything unless you make phone calls at the same time and you wont be able to if you use the master socket's internal socket.
Try a different filter.
Get the line signal noise ratio from your router
And Bit Error Rate
and power
Check these are OK
If you are on fancy broadband (12M suggests you will be) check that your BRAS is not turned down by asking the ISP.
Reboot your router to make sure that it has not run out of memory or some-such. Be aware that with modern fast DSL the exchange and may interpret frequent router reboots as line noise and turn your speed down (BRAS).
Eliminate your router's DNS management. Set a static DNS server in your PC. Leave the address on DHCP.
Use say google 8.8.8.8 and if you like OpenDNS or other free one.
You could try a decent router to wall cable. I have once found a really nasty untwisted ribbon cable was spoiling things.
To test DNS use nslookup - it always checks with the conigured DNS server.
C: \Users\fred>nslookup
Default Server: google-public-dns-a.google.com
Address: 8.8.8.8
> bbc.co.uk
Server: google-public-dns-a.google.com
Address: 8.8.8.8
Non-authoritative answer:
Name: bbc.co.uk
Addresses: 212.58.244.22
212.58.244.23
212.58.246.79
212.58.246.78
Have fun.
Last edited by jimjim1; 9th Oct 2016 at 22:28.
Reason: added a bit