Moving a coax aerial socket help =)

Hello, I have recently moved into a new house and the previous owner had their TV mounted on the wall, we have a TV stand so have no use for the bracket or the sockets that are half way up the wall so it looks a bit unsightly.

I visited screwfix yesterday to get some supplies to do the job.

I got two male connectors and a female to female connector, some plasterboard socket back boxes and some coax cable from selco, I connected everything up by taking the socket off and wiring the male connector to the existing wire then using the female to female connector and a length of coax I made then I connected that to the socket to test it before I plastered the wall and, the signal was fair but I noticed it was pixellating and not perfect, I'm only moving it by a meter or so down so I don't get why the signal loss is so bad.

Any help would be much appreciated as I intend to do the job today.