The T4 is left ON. After about 6 minutes it will go into hibernation. IF you turn it off and the parabola drifts a little you lose the signal. In hibernation, if it drifts it will auto come back on and lock in the signal before you lose the Picture. Doug
PS from the manual.
After the T4 has verified the correct satellite, it will
continue to track the signal. The unit will go into โSleep
Modeโ if the vehicle is stationary for 6 minutes. This
involves a quick verification process where signal may be
lost, then return to the signal and be silent. If the vehicle
begins moving greater than 10 MPH, the in-motion T4 will
resume tracking mode.