Grandude,
Quad-shielded RG-6 may sound like overkill for OTA, but the extra shielding is critical in areas where strong OTA signals exist. If you want some ugly multipath situations, try using a 50-70% shielded RG-59 cable, which will let in the same signal being pulled in by your antenna, but smeared-out over several nanoseconds.
How much money are you saving by using RG59 vs. RG6U? $10? $30? I'd spend the money, even if I had RG59 sitting around (which I don't 'cause I throw that $#&^ out!)