George,

I don't have dropout issues with Dolby Digital with OTA HD unless I get a visible picture distortion as well either in the form of pixelation or other breakups.

I've used a Dish6000, Dish811 and Dish211 into the 568.2MN, 861 and G68 with the same results.

Wish I had a better answer but at this point in time, I don't.

Cheers,

Surround Music Fan/Computer Geek/Curmudgeon in training.
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861v4, HD621, Panasonic BD-P55K, Toshiba HD-A35, Oppo HD990, Dish Network 622, Pioneer DV-668AV-S w/ DVD Upgrades mod, EW Fontaine II (x5), Velodyne DD-15 (x2), Seymour AV Ice blocks (x7)