BB doesn't work unless phone is off the hook.

Question

I've had problem with Broadband for years, it goes through bad patches and eventually gets better. It's currently in a bad way again, days of no connection at all and at the moment off and on services lasting minutes or hours. It's been worse in the past but I've never tried getting help from the people on this forum before.
So today for example Internet was working maybe 30 minutes (tends to be potluck) then couldn't connect. I do what has become second nature, dial 1471 and leave phone off the hook. This tends to get the Internet going again for 20 minutes.
Last time, a few mouths ago, Internet stopped working for a week, then even the trick of using the phone stopped working. As there was a lot of crackling on the line I reported a line fault. Unfortunately on the day the engineer came the line was quiet. Internet was still down so he did something along the lines of increasing the voltage on the phone line. A few days later Internet was mostly stable so I didn't pursue things with BT.
Test 1 (phone has to be off the hook) - 19:15 ADSL
ADSL Line Status
Connection information
Line state:     Connected
Connection time:     0 day, 00:01:24
Downstream:     2,880 Kbps
Upstream:     160 Kbps
  ADSL settings
VPI/VCI:     0/38
Type:     PPPoA
Modulation:     G.992.1 Annex A
Latency type:     Interleaved
Noise margin (Down/Up):     7.3 dB / 5.0 dB
Line attenuation (Down/Up):     62.0 dB / 31.5 dB
Output power (Down/Up):     17.7 dBm / 11.7 dBm
FEC Events (Down/Up):     31 / 76
CRC Events (Down/Up):     0 / 20
Test 2 (phone has to be off the hook) - 19:20 BT Wholesale Broadband Performance
 Download speedachieved during the test was - 2.49 Mbps
 For your connection, the acceptable range of speeds is 1.2 Mbps-4 Mbps.
 IP Profile for your line is - 2.54 Mbps
 Upload speed achieved during the test was - 0.12Mbps
 Additional Information:
 Upstream Rate IP profile on your line is - 0.45 Mbps
Test 3 - 13:55 Quiet Line Test
There's some hissing and crackling every few seconds. I've heard a lot worse but there's some noise.
Maybe another engineer would make more of an effort and get this fixed, maybe there's someone I can call to get voltage turned up, I'm not sure what's best any suggestions welcome.
P.S. I've been using the Test Socket for last few days. I'm also wondering if the line fault is, say in the loft where Phone line comes into the house, do I have to pay?

Answer 1

Your problem is being most likely being caused by a corroded joint or crimp connecter, probably in the street cabinet or the pole (if you are fed from one).
The corrosion creates a high resistance connection and impairs the broadband and the phone. This manifests itself as crackling on the phone.
When the phone is off the hook, it allows current to flow through the corroded joint. This breaks down the high resistance connection, and allows a better broadband connection.
This does not last long, as once the current flow stops, when you replace the phone, the resistance soon increases again, and you are back to square one.
There were a large number of crimp connectors which were used on the external network, which allowed moisture ingress, causing corrosion. Many of these have now been replaced, but there are probably thousands of them out there in the external network, many of which, give no trouble.
The replacements are filled with a gel, which prevents moisture ingress, and these are now fitted as a matter of course, when noise faults are reported.
There are some useful help pages here, for BT Broadband customers only, on my personal website.
BT Broadband customers - help with broadband, WiFi, networking, e-mail and phones.