A:AnswerWe connected ours to the splitter and each of our TVs are fed a signal from there. The amplifier was installed after the antenna but before the coax splitter input.
A:AnswerROKU and Antenna work independently of each other. ROKU is driven by WIFI signal while the Antenna picks up broadcasted signals through the ether.
A:AnswerThis is a very directional antenna. I have an issue where the tower is partially hidden behind a hill and I had to change the location of the antenna in order for it to work. This may be party of your issue. Move it around and then remember to continually reprogram your tv each time you move the antenna