I'm having some real issues with ABC (7-1) giving huge random blocks of digital noise every few minutes. Only about 7.5 miles from the Sears Tower. Signal strength is 80 or better. Occasionally see it on NBC (5-1) as well, but it's really obnoxious on ABC.
Antenna is a Radio Shack "UFO". No discernible reduction in this strange digital blocking by adjusting gain, location, or "channel" on it.
Marantz AVR & monoblocks + MartinLogan Motion 3.1 setup