I had the ubiquitous "49% Blues" as well (jumped from 0% to 49% and back, no lock) on all but 1 series of PBS HD/DTV subs, from a tower at about 25 miles. I'm in a fringe and my 25 year old OTA has a B-T hi-gain amp (~50 ft cable between the preamp and ps) then split, then about 50 ft more to my 811's location. Just for the heck of it I inserted a cheapo 10dB amp into the line after the split. Voila! 1 new HD channel (ABC) with 3 more subs on 2 different virtual channels (CBS and FOX - neither is HD yet - towers are both about 40 miles away). So far this has worked fairly steadily, but I may lose it all when the leaves are back, etc. I'm not done playing yet, tho' - I still need to get NBC HD at about 60 miles. BTW - the OTA tuner in my TV is a bit better than the 811's, but I like having these channels in my program mix so I generally tune with the 811. Can't wait for the 622 improvement - might be enough for the NBC digitals (real channel 34).