Most news media rely on satellite uplinks, take out the satellite dishes on the roof and they loose those feeds, I'm sure they could reroute the transmission via internet cables but to my knowledge most broadcasting is done by satellite. Anything under .338 is probably a bit too wimpy to act as an anti-material round. Alternatively how many broadcasting stations do you figure have working generators? Because transformers take a while to replace and only a fraction of a second to destroy. Imagine how successful the DC beltway snipers would have been at creating havoc if they used a subsonic and suppressed round like .300 blackout on soft and fragile material targets like power and media infrastructure. It's also worth noting that a cordless band saw, much stronger than a sawzall, can cut through just about any gage of steel cable, like those cables which stabilize power, cellphone or internet infrastructure towers using tension.