I'm on an FTTC connection (although I don't think it's particularly important in this case).
After quickly looking at how my line has performed today, I saw this huge spike in ping times just before 6pm.
I'm assuming that the spike is caused by when I went out to mow the lawn quickly whilst the rain held off - the times match up. Now when I was on ADSL, I remember the snrm would plummet to less than 1 whilst the electric mower was used, and although the sync would hold - I couldn't transfer any data at all. Am I right in presuming this is the same thing (I wasn't able to check the line stats whilst mowing).
What actually causes this though?
And is it related to a brief comment the Openreach installer made whilst doing the install: Whilst trying to get the physical line stats, he tried to get an earth from a nearby radiator. Whilst it was earthed, it wasn't a very good one. He then tried with an earth directly from a socket - which gave a similar outcome. He just mentioned it must be a bad earth area in general.