I wonder how much of satellite transmissions have gone digital (and thus, likely to be something you could only jam and not replace) in the ~20 years since I was working in the industry. It wasn't even really on the radar when I left the business; even stuff that had a major digital component, like automated advertising feeds, were still being transmitted analog for the video and just the metadata was digital and sent via another mechanism (internet, I think).
Nobody's running the F1 race from tape...
I'd be curious to know if there's much digital and/or crypto in those signals too - part of me suspect the satellites themselves are mostly "too old" to be doing anything except analog - although I do sometimes notice the resolution on MotoGP races drop significantly, I think that's last mile cable bandwidth problems when the Sunday night movie starts pumping full HD into all my neighbours houses, rather than the signal from space...
Most satilites operate as a really dumb "bent pipe".
You transmit a signal on one frequency, and it amplifies and re-transmits that signal exact same signal on another frequency.
There is no decoding and re-encoding of the signal. The satilites is completely agnostic to the formatting, and encoding of the signal. All you need to do is replace the equipment at each ground station and you can transmit encrypted digital.
On the flipside, I don't think satilites do any authentication of the signal they are retransmitting. If someone transmits a stronger signal, the satilites will lock onto that and retransmit that instead.
However, the receiving equipment probably does authenticate and won't accept the hijacked signal, so all you get is a jamming effect. But the satilite itself is hijackable.
Here's an anecdote about one sport in particular - UK horse racing. There's a pay TV channel (Racing UK) that broadcasts races live. They would bring their broadcasting equipment to each track, and upload the live raw video over a satellite link. This stream was then downloaded at their head office, where it was mixed and graphics were added, before it was re-uploaded to (another? the same?) satellite as the 'official' TV channel.
With the right equipment, you could view the raw video feeds yourself, rather than watch the re-transmitted official channel. This gave just over a second or so of improved latency, which, for some serious in-running gamblers, was a crucial advantage. But about five years ago, Racing UK started encrypting their live feeds. Nowadays, only a few people with insider information can obtain the 'faster' video...
The version I read said they changed link frequencies. Presumably they have a secondary link on a different frequency for when a transmitter is down or they need to broadcast two feeds.
In the old days you'd need someone at both ends to make the change, though, and towers are normally unmanned. Which may explain why it lasted so long with the first transmission and was short in the second...maybe the station had someone standing by at the tower to make the change when/if Max returned. I dunno. Our tower was a good 30 minute drive from the station (which is common, I think...stations are usually centrally located, but the towers are out in the boonies a bit because of the need for cheap land and freedom to stand up a heckin' big tower).
Seems the opposite, first (short without sound) was on WGN around 9:15 pm and second (longer) on WTTW after eleven
It's probable, though, that the signal is now signed and encrypted and thus not easy to hijack. Then again, satellites were also broadcasting syndicated shows and news feeds in the clear back then, and probably now, for things that aren't premium channels. It was assumed that if a signal was coming down from the right satellite at the right time, it was the right content.
That said, even back then, it was non-trivial to hijack that signal. There's only a few points of entry: In the station itself, inserting a microwave signal that's closer to the tower or maybe more powerful than the one on top of the station, or in the satellite feed (which has a couple of points of entry, as well, but that would be interruptible by the station master control operator). The microwave transmitter would have to have line of sight to the tower, further complicating matters.
The article suggests that the station employees were able to "stop" the second hijacking quickly...I'm not sure how that would happen if it was a microwave hijacking. They maybe could have boosted the microwave transmitter output at the station to push the imposter down into noise, but those are regulated, I would think, and probably don't have much wiggle room.
I dunno. Even as someone that has worked in TV I don't know exactly how they did it, which makes it all the more fascinating that they did. The simplest thing I can think of is getting into the station and faking all the noise to make it look like it's "merely" a microwave hijacking. Then again, microwave is not terribly advanced technology, it is available on the surplus market, and if you can get closer to the tower with your transmitter, you don't need a whole lot of power. So, that's probably how it was done.