Cuts improve broadband

Our neighbours have a man in to replace their old garden fence. He’s a friend, I had a chat with him while he was digging the holes for the new fenceposts and mentioned that our broadband and phone cables run along the boundary between the two gardens. He pointed out that he’d already noted their presence.

Unfortunately, a slip of the spade and an errant clematis root led to the severing of our information artery. He was very apologetic and carried out a repair with a couple of coax connector blocks and a phone line coupler. He asked me to check our broadband, phone, and TV before he would embed the new connections in resin to preclude water ingress and prevent corrosion.

Now, here’s where this story gets weirdly interesting. Once the broadband was booted up, I ran a speed test on the connection. Seems we are now getting a 50 megabits per second greater rate than we are paying for. We seem to have jumped from a nominal 150 Mbps to well over 200 Mbps. Now, I don’t know for sure whether our provider was already pushing us speeds of 200+ but, that’s not what our account says, so, that’s nice…

It gets weirder, Mrs Sciencebase received a couple of landline calls, actually from the fence man, and she reported back that the phone seems rather more clear now than it did before.

So, how could that be? How can cutting and repairing a wire improve anything? Surely, the presence of those metal connectors halfway along the cable between the roadside box and our inlet junction would lead to some kind of degradation. I was expecting our connection speed to be a little lower, if anything, not more than 33% faster.

I asked another friend, an engineer, who has worked in the telecoms industry for more decades than he would perhaps care for me to admit on his behalf. He correctly surmised that we had a cable provider rather than upgraded phoneline broadband.

“Your provider uses a broadband protocol called DOCSIS, version 3.0 here, which is nominally 200 Mbps max,” he told me. “This protocol is quite sensitive to signal levels – too strong a signal is just as much of a problem as too weak. If the signal level is wrong, the speed suffers. They’ve obviously adjusted the signal level better at the green box.” So perhaps what was happening was that we had a strong signal that wasn’t working optimally but the cut and reconnection have taken the top off that strength just enough to make it work slightly better.”

Perhaps now that we’re back up and running it is time to add a more reinforced sheath to the cable so that an accidental severance doesn’t happy again, I cannot imagine that we would get a speed boost a second time with another splice.