Basically, the TV station didn’t run the high powered broadcast towers directly. They simply beamed the signal over to the tower (using directional antennas) to get amplified. All the hacker did was overpower that (relatively low power) directional antenna signal. It would require being in closer proximity to the tower, but it would at least allow you to get the signal amplified using existing infrastructure, instead of building your own amplifier.
The latter is essentially how they did it.
Basically, the TV station didn’t run the high powered broadcast towers directly. They simply beamed the signal over to the tower (using directional antennas) to get amplified. All the hacker did was overpower that (relatively low power) directional antenna signal. It would require being in closer proximity to the tower, but it would at least allow you to get the signal amplified using existing infrastructure, instead of building your own amplifier.