I recently ran a new coax from my existing OTA antenna in the attic down to the multisiwitch on my dinosaur one-satellite Direct TV system. Connected it to the OTA input of the multiswitch and installed new diplexers at each TV/receiver location. Weird thing is, I get different OTA channels at each lcation - 29 channels in the most "remote" location, 24 right next to the multiswitch, and 21 in the "middle". Naturally, the two local HD channels I want most are missing from the location where I do most OTA watching. Would a signal amplifier help this situation, and where should I install it, upstream or downstream of the multiswitch?