Can anyone explain Phantom Power and, specifically, how it's used in satellite television systems?
Basically, it's AC superimposed on DC, with a filter to separate them out at the other end

Satellite TV line-power schemes (and other power-over-coax setups) work by simple superimposition; they add the AC signal atop the DC supply voltage on one end using a coupling capacitor and RF choke to create a summing node, and then use a filter (coupling capacitor and RF choke) to separate them out at the other end, as follows (although the values certainly aren't right, and OA1 is really a generic amplifier block):







simulate this circuit &ndash; Schematic created using CircuitLab

Note that this is not the same as true "phantom power" as applied to balanced lines such as pro-audio mics and PoE; these setups have the DC voltage set as a common-mode voltage from both signal lines to ground, or between two pairs of signal lines for that matter.