I'm in the Northwest and have a 24" dish that I supplied myself. Being a Dish customer, I already knew that an 18" dish would not cut it for 61.5. Saturday, a horrendous rainstorm came through the area and I watched the picture go black at 71 and the strength continued down over the next 5 minutes to ZERO! Then it started climbing back up and as it passed 71, my picture came back.
After the rain stopped, I went outside and tweaked my dish and the signal went from around 87 to 95. This should be enough to get me through the marginal periods like on Friday night when my signal hovered around 67 for about 30 minutes. With this extra 8 points, I would have had a signal. I'll never be able to completely avoid signal loss but I don't expect to have a picture 24/7 either. I know the limitations of the 61.5 bird and if I need to I will get a 30" but even that will not prevent occasional dropouts. Thankfully, I have OTA as a backup.