TBC...It's lying across the rafters. I'm going to try an amplified indoor to see what result I get. There may well be something (break IN the cable ??) that I'm not aware of that's causing it. Will let you know in a day or so.
What I use in the loft is a bracket for a satellite dish like http://cms.killercontent.net/media/e...satbracket.jpg which is fastened to one of the beams with 2 screws or bolts.