I've lived through a couple of DTV satellite swap outs and it can be very time consuming for the technical crews involved but usually transparent to the customer as mentioned. Once the satellite is parked and the kick stand is out, new transponders will need to be turned up one at a time with various satellite parameters closely monitored for a time before the uplink center can light up the transponder. Uplink levels and sometimes spacecraft attenuation levels would be adjusted to find the best saturation and operational point and if the spacecraft transponders have ALC or AGC that will have to be disabled for saturation procedures, then turned back on for normal operation. All this requires commands to be sent to the spacecraft, which makes the TT&C folks very nervous as any mistake can be catastrophic.
If all traffic has been shuffled off a particular transponder that is being replaced then all of the above can be performed and traffic can be uplinked to the new transponder in parallel with wherever it was shuffled to and a change in the program guide will then point customers to the new spacecraft and transponder. A lot of people will be very busy during the transition from the company flying the spacecraft to people from DTV engineering, Technical Services, Broadcast Operations, Program Guide, etc. At no time in this process is any programming viewable in the clear as in FTA.
If all traffic has been shuffled off a particular transponder that is being replaced then all of the above can be performed and traffic can be uplinked to the new transponder in parallel with wherever it was shuffled to and a change in the program guide will then point customers to the new spacecraft and transponder. A lot of people will be very busy during the transition from the company flying the spacecraft to people from DTV engineering, Technical Services, Broadcast Operations, Program Guide, etc. At no time in this process is any programming viewable in the clear as in FTA.
