Dan Could you do me a favor? look and make a tree diagram of your splitters and show on every split how much signal loss there is... Just pulled one three way out of my desk. And it has 7db 7db and 3.5 db of loss. If you "main" tv is dropping out at higher stations to me that seems to be the culprit. Why you ask? TV stations operate at different frequencies through coaxial lines... lower stations such as 2,3,4 operate lower down the band while your 100+ channels are way up there. Try rewiring where you have the least DB loss such as 3.5 DB.