Your location is Very Close to the Tv transmitters.
The signal strengths are -->Very Strong<--.
Yes , Tv signals can be Too Strong.
And the Strong Signal multipath , signals bouncing all around is Not Good for reception.
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Tivo , Digital Broadcast Tv Tuners have - ongoing - issues - with there ability to deal with less then perfect digital reception.
All digital broadcast reception is less then perfect.
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I recommend use a Antennas Direct 1296F variable attenuator , to Dial Down the signal strengths of the Tv channels and at the same time will Dial Down the reflected bouncing around signal Tv reception.
Can buy the 1296F attenuator at ,
http://www.amazon.com.
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As a Test of reception , I recommend -->By Pass the Tivo<-- disconnect the Tivo -->Completely , and connect the antenna Directly to a Digital Tv.
Digital tuners can develop - Digital Glitches - that are not cleared out with a simple channel scan.
Do a Double channel scan.
http://www.dtv.gov/rescan.html.