I do the same thing, run the antenna through a tube inside the plane. But a couple of months ago, I was testing a Giant Goldberg Tiger for a friend, and I kept getting hit on short final. So I changed my pattern up, made it real tight and tried to avoid the geographic location where the previous hits had occured. It landed fine. Then it occured to us that the tube was straight as a string, going through the fuselage and might have been completely blanked out by the engine when the plane was coming straight at us. We rerouted the antenna and the problem didn't occur again. So, maybe there is something to it, especially if the engine is a big one. I don't know, I'm just saying...