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The power required to do it is impressive to say the least.
I guess the other option would be that the signal was created with very close proximity to the broadcast tower requiring much less power, but they probably had a limited area to search.
To me it almost reads like this was a "we technically can, let's test it out!" And it worked.
You have no idea how much of that goes into broadcast engineering
That's not how the attack worked. He didn't drown out the tower. He simply overrode the the studio-to-transmitter link signal. The studios used microwave line-of-sight transmitters to communicate a signal from the studio to the tower. All the attacker had to do was override that signal. That signal was 50W max. You could override it with maybe 200W as long as you were also in line-of-sight of the microwave receiver. Probably less since some microwave trasmitters were as weak as 1W. They don't need to be strong since they are line-of-sight directional transmitters. So, that's not particularly impressive.
Although, having to get a transmitter within line-of-sight makes the overall feat more impressive.
It would require as much, or more, power to drown out a TV broadcast signal at the source. I believe many of the old towers were 200kW-1000kW so it would have taken one hell of a pirate signal if interfering close to the main source. However, RF follows the same principle as light using the inverse square law so the further you get from the primary transmitter, the signal quickly becomes exponentially weaker for any receiver.
If you had a TV transmitter on a small hill that is a fair distance away from the target audience, like many were, splitting the distance with a directional antenna wouldn't require nearly as much power from the pirate signal to overtake the original transmission.
If I wanted, I could interfere with ham radio signals with as little as a watt of power (in my immediate local area) even though people might be communicating through a ham radio repeater that transmits at a couple of thousand watts that is many miles away. (It's actually a permitted emergency technique to "break into" active conversations. Actually, other ham radio operators are familiar with what interference sounds like, even for signals that can't fully overtake a transmission. It's customary to stop the conversation if detected and wait for the "break".)
Yeah, growing up there were people with illegal high power CB radios that would bleed into the TV signals near me. And I don't even know if they're close to the same band.
Doesn't need to be in the same band due to harmonics and power. If you keep splitting the 11m band (CB) into "fractional-frequencies", you are going to get a cross-over somehow, especially if the fundamental is at super-high power.
Using a piano as an example, if you play a C2 at 62.41Hz it still expresses harmonics at C3 (130.81Hz), G3 (196.22Hz) and C4 (261.63Hz) and at least in theory, to infinity and beyond! Each harmonic away from the fundamental will be expressed in decreasing levels of power. (It's like 1/3 power per, I think. The proper math is out there though.)
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.
Didn't they just overpower the radio link to the broadcast site, a much lower power signal than the broadcast signal itself?
(sorry to add even more; I just made another comment about this and I am familiar with most of these concepts.)
Actually, that would be much easier. TV stations back then mostly received shows via satellite dish. Pointing a low power directional antenna directly at the dish's LNB would work great. Satellite transmissions weren't strong and were rarely encrypted back then so that would theoretically be super easy if you knew your RF and deep RF knowledge was much more common place +30 years ago.
I am not sure if they used point-to-point microwave antennas back then for TV, but it would be the same concept. (Microwave antennas are typically the round, cylindrical looking, covered antennas we see all over the place today.)
FWIW, it mentions in the link that the method was via overpowering the analogue microwave link between the station and the broadcast transmitter