[TowerTalk] Coax and asphalt shingle roofs

[Bill Ogden]

This is my month for questions. I am looking at placing a receiving loop 
(and a rotator) on my roof. The roof has architectural asphalt shingles. 
What is a reasonable way to get coax and a rotator control cable to the 
loop?  In my case, I cannot access the roof point from inside the house. 
How should I protect the cables from the rough shingles? And protect the 
shingles from being rubbed by the cables? If the answer is conduit, should 
it simply lay on the shingles or be raised somehow?

Bill
W2WO