91w reception on dish 500?

[jmdumble]

So I am able to receive 91w with my Dish 1000 (roughly 20x25) between 100% to 75% on most transponders in the D/FW, Texas area. I tried to set the same receiver up at my fathers house (which is activated) a few miles away and I can not get a signal with his dish 500. Am I just having issues aiming it properly or is the dish 500 too small to get a signal? I'm almost positive I have it aimed spot on.

Thanks for any help,
Jeff