Have you checked to see if anyone has a really old TV generating an EMP?
I read that story, and it's exactly what happens here whenever there's a thunderstorm. Each flash of lightning knocks out the broadband for ten minutes or so, even when there's no power interruption. I guess it must be something similar to the pulse from that TV being turned on.
Our broadband issue is just the length of the copper loop from the cabinet. We're only a few hundred metres from the cabinet, but it's on the other side of the valley, so the copper wire takes a detour up the valley and back down the our side. What we would like is to get a fibre strung over the valley, on the poles that carry power over, so we can have FTTP, rather than the pretty sluggish FTTC we have at the moment.