http://www.forum.tvfool.com/showthread.php?t=13156.
As a Test to prove reception , disconnect the preamp (box thing) unit at the antenna , disconnect the power injector that supplies power to the preamp unit at the antenna , disconnect the power supply that is connected to the power injector that supplies power to the preamp unit at the antenna.
Connect a NEW long continuous length of coax to the antenna and run the NEW long continuous length of coax through a open door or open window , direct to 1 Tv.
A continuous length of coax , No potential trouble causing , couplers , splitters , etc. .
At your location , a minimum of these Tv stations should be received without an amplifier.
K18EL-D , Mynetwork.
KOPB-TV , PBS.
KGW , NBC.
KPXG-TV , ION.
KPDX-DT , MyNetwork.
KRCW-TV , CW.
KOIN-DT , CBS.
KATU-DT , ABC.