How accurate are speeds on dslchecker.bt.com?

How accurate are the speeds on dslchecker.bt.com?

My cabinet was just activated for FTTC: https://puu.sh/urRpt/1f94e31489.png

Are these speed estimates for FTTC conservative? Do you think I could actually get a higher downstream speed than the 53.5Mbps top figure it claims I can get?

The distance from my home to my local cabinet is about 470 meters, according to this chart: http://www.increasebroadbandspeed.co.uk/2013/chart-b...

this means I should be able to get around a 60Mbps downstream speed, which is 7Mbps higher than the dslchecker says I should be able to get?

So, what do you guys think?

They're usually pretty accurate and I believe they take into consideration an element of crosstalk.

Just because you're 470m from the cab doesn't mean your line is that long. The routing often doesn't take the path you'd think.

If it means anything the checker shows max downstream 70.3 on clean for my address. I get 76 sync though with dated wiring. So it is possible that you could perform better than this estimate but it is not a guarantee.

They aren't very accurate for new builds. For my line the impacted range in the checker is 36.3 - 22.3 Mbps when the reality is the line can only support c. 16 Mbps. Somewhat less than the 28 Mbps minimum BT suggested I would get.

Normally they are fairly accurate.

How accurate is your 470 metres? Is that the actual path length? Does it take into account the FTTC cab to PCP distance? And then distance from PCP to house? What about the extra 5 metres to go up the pole? Or maybe 2 metres for the drop underground? Or a loop inside a footway chamber? Or the run from eaves to socket? All though little bits can soon add an extra 10 to 20 metres and thus a further drop in potential speed.

Simon, I know you've been in these forums a long time, but have you picked up that new builds, which you imply you are in, can have disastrous (for broadband) internal phone wiring? Including the physical cabling used, quite apart from the way it is wired up.

Plus of course the usual lack of optimisation by many users. Several megabytes difference can ensue.

If you haven't already made sure none of this applies to your line I suggest a new thread with an appropriate Subject might help you.

(And your Profile says ADSL2+).

Post deleted by kasg

In reply to a post by simon194:

They aren't very accurate for new builds. For my line the impacted range in the checker is 36.3 - 22.3 Mbps when the reality is the line can only support c. 16 Mbps. Somewhat less than the 28 Mbps minimum BT suggested I would get.

Whilst I agree somewhat, it's mostly down to the poor cabling builders use.

6m of internal wiring from the entry point to the NTE (installed by Bellway) caused my ADSL signal to drop from 2.7meg, to 0.6. I dread to think of the impact it would have om VDSL.

In reply to a post by mattocaster6:

Are these speed estimates for FTTC conservative? Do you think I could actually get a higher downstream speed than the 53.5Mbps top figure it claims I can get?

The ranges quoted are meant to come from similar lines - which means they have a similar amount of loss (attenuation) measured between the cabinet and the DP at the top of the pole.

The figures at the top and bottom of the range are meant o match the 20th and 80th percentiles - while means 20% of "similar lines" get speeds better than the top, and 20% get worse than the bottom.

Those "similar lines" will all have some amount of crosstalk (interference from other FTTC subscribers). On a new cabinet, the first people to sign up are likely to get significantly better speeds at first ... but as more people sign up in your neighbourhood, the speed will fall - usually to within the range somewhere.

Openreach will investigate slow lines, but the range they choose (A or B) will depend on the installation method used:
- ISPs that use self-install tend to quote the B range speed, so will only investigate when your speed is well below 26Mbps. For example, TalkTalk
- ISPs that use engineer installations tend to quote the A range speed, so will investigate when your speed is well below 39Mbps. For example, Plusnet.

Don't go into this thinking you can get 60Mbps, never mind keep 60Mbps even if you start with it.

I've read plenty about the potential wiring issues in new-builds. In mine the cabling comes into the house through the wall and runs behind the plasterboard and has the bedroom extension connected to this somewhere before it reaches the master socket.

Sky arranged a visit from an Openreach engineer last Monday because the speed was significantly below their 33 MBps minimum they quoted. I politely asked him if he could run a new cable from the BT66 to the master socket to cut out the original cabling which he did. The sync only went from 14 to 16 MBps which was probably because he did a DLM reset.