I was referring to the tv tuner, whether it be internal to the tv, or external. Long ago, I noticed my built-in tv tuners weren't nearly as good as my external Hauppauge, KWorld, and HDHomerun tuners. Those picked up and locked onto channels the built-in tuners couldn't. Give one a try if nothing else works in the short term. While not the best tuners, the cheap Walmart digital tv convertor box's will give you an idea if your tuner may be damaged.
Your signal levels are very strong, and you should be even able to pick most of those up with a straightened paper clip serving as the antenna, as long as multi-path isn't the issue. If it's multi-path signals interfering, then as RetiredEngineer said, a very directional antenna may help.
Ask around, see if others in your locale have problems with reception.
Last edited by Don_H; 08-17-2014 at 10:16 PM.