I would check the connectors on both ends of the RG-6. If there is any doubt whatsoever, you should reterminate both ends with new connectors. If they are okay you can swap the cables at the LNB (I'm assuming you have a dual LNB) and see if the problem follows the RG-6 or follows one section of the LNB. If you are certain that the connectors are okay and the problem follows the RG-6 then, yes, the RG-6 should be replaced. If the problem follows the LNB, it's time for a new one, available at a very reasonable cost at places such as Wal-Mart, Radio Shack, etc. Good Luck..................