I would have thought signal strength also, but most of mine range from 90-100 on all satellites. Also a reset usually corrects the problem, but thats several minutes of missed viewing, interupted recordings, etc.
I didn't mean to use this thread as my personal rant, but no one should be led to believe the HR's are problem free.
Have you tried having D* come out and look at the dish anyway? It could be something as simple as a loose nut or something that causes the signal to go away from time to time... those new channels are pretty touchy if everything is not set up perfectly.
Just a thought.