I just had the same issue. I decided to upgrade to a new winegard antenna with the batwing. I also added a sensar pro box to replace the original in my 2001 Beaver DP.
I used a cable tester after I removed all three tv cables and tested all the cable and marked them all.
When I tested the cable at the connection at the roof to the booster I was getting an intermittent signal so I knew that the section of cable had an issue. I pulled the cable up through the roof after getting all the sealant peeled away and found a torn piece of cable showing the shielding and the center copper and it was kinked some.
I removed the cable wire by fishing a new section of cable from the antenna to the sensar pro direct.
Hooked all the wires back up and tuned the antenna in using the sound and turning the antenna to the strongest point. I then scanned all three tv's and was amazed at how many signals I recieved (33) and the closest stations are 40-50 miles away from my home. I should have spent two days a long time ago doing this...