There isn't enough bandwidth for three HD broadcasts on the same channel. 7.1 (CBS) will probably be HD while 7.2 (FOX) and 7.3 (ABC) will probably be SD. Channel 27 in Youngstown is running two HD programs at the same time (CBS & FOX); however, the picture quality suffers slightly, especially during fast motion.
I'm getting a rock solid signal quality level between 75 and 80 at approximately 60 miles from WTRF's transmitter here in Salem on my Dish Network ViP 622. The maximum is 100.