problems with mtnl fttc.

Yup it has one joint but after i insulated the cable which enters from the wall hook about a foot or so, im getting 10.1 snr. So i think my problem ks solved ill leave it like this and if it troublz me again maybe replace the whole wire from junction box with 26 awg shielded wire. Thanks for your help. Ive to call up these mtnl guys and tell them to stop using this shit wire.