I want to move the router and bought a 5 metre RJ11 cable. To my dismay, changing the cable resulted in a 12mbps drop in speed ! I changed the cables a few times, in case I had a bad link, same result. I bought another new cable, in case the first one was faulty. Nope, same result.
I then found a 5 metre cable made with CAT5e so bought that, the drop was only 10mbps, but still very significant. All told I now have four 5 metre cables, from different sources (to rule out a bad batch) and get the same problem if I swap in a 5 metre one.
I brought this up on the EE community forum and have also contacted EE tech support. Nobody seems to know why changing the cable for the same spec or even better spec would cause such a drop in speed.
EE have done remote tests on the router, all is OK as far as they can tell. They have no idea why I should see such a drop in speed and have nothing on their system from other customers like this. The line itself was re-provisioned in July 2017 and fully checked by Openreach at the time.
I've a few ideas to try. One is to swap out the router and try another, I have one on it's way. Another is to make an extension to the Openreach socket and put a broadband splitter on so the change in distance is via phone line, not the RJ11 wire.
But, it still sounds odd that a short distance change in a bit of cable can cause such issues... Just to test the theory that it is significant I'm going to try a short run of cable too, see if that bumps the speed up at all
Has anyone ever seen anything like this though ?