I'm beginning to have reception problems on sat 61.5 due to trees (I'm pretty sure). However, I seem to be losing a channel on transponder 30 (434 NESN)while channels on transponder 5 (Boston locals) are working. Is this possible? Can a signal be weaker on different transponders? The trees in question are very tall and not on my property, so I'm not sure how to solve the basic problem just yet.