The Dish box has to send commands back to the antenna; at least the Dish Trailblazer antenna. The built-in amplifier will block this. Somewhere on this forum I have seen a mod to the built-in amplifier to allow the signal to be sent.
Since I mainly only watch the TV in the living area, I just keep the Dish amp in the cabinet and run the cable from the Dish antenna through the kitchen window.
Added: HWH Kick-Down Leveler; RoadMaster Anti-sway bars; Tornado Rotary Tank Rinser; Accede Backup Sensor Kit; cylinder locks (w/one combo lock); custom sink cover; Kenwood DDX 5706S front radio; Pioneer MVH-X5560BT rear radio; Oxygenics Shower head; ScanGuage II; Blue Ox Tow Bar w/RVi Brake 2; Winegard Rayzar Automatic TV antenna; Trimark Steel door lock; Dometic 310 toilet; whatever is next.