Ok. I finally have the problem solved.
I started over in my attic where I connected the coax down-lead from the antenna to The New Winegard Boost Dual Channel (one UHF, one VHF) PRE-AMP= This one:
https://www.ebay.com/itm/LNA-200-TV-....c100005.m1851
I had purchased this WITH the Winegard HDA-200 but I am not using this amp.
Three weeks ago when this issue first presented, I ordered this:
https://www.amazon.com/Viewsonics-VS.../dp/B007ZEUMAW
so I used a Winegard power injector between the preamp and Booster Amp. That output goes to the splitters in the basement.
I tested this setup by doing a channel scan. Received 28 channels and no (ch 42) 29.1 out of Philly.
Then I realized that Comcast, long ago, had installed a Viewsonic VSMA 601
c immediately before my splitters in the basement. I removed this unit and did another channel scan. This time, I received 40 channels including all three 29.1,2,and 3 with a perfectly clear picture and no pixelations.
Is it possible that too many amps in the line cut off the tops of the RF waves (overloaded)?
I don't have any test equipment so I was really frustrated but, I have a combination of components that works for me.
It wasn't the station. All other stations came in. It was just (42) 29.1 Fox Philadelphia. Very strange (to me). All fixed (todo bien).
Thanks, everyone, for your interest and helpfulness.