A bit of discussion re. the DB8E:
http://forum.tvfool.com/showthread.php?t=13198
I own a DB4E, the build quality is quite solid. Without having the DB8E in hand, I'm inclined to expect performance in the same class as the 91XG, DB8, CM-4228, U8000, HD8800 and HD9095P. The specs suggest it should have the highest gain of all it's peers... the unanswered question is, 'what's the actual harness + combiner loss'. See notes 2 & 3 on page 1 of the manufacturer's published
Technical Data Sheet.
Your TVFR is a good example supporting the axiom, 'Reliable reception starts with the selection of the antenna
and it's location'. It's clear that you'll need to consider mounting higher if possible. Feel free to post TVFR's for higher antenna elevations... it would be interesting to see conditions at 30', 40', 50' & 60' even if you know you can't go that high.