A radio signal hack is what made those Dallas warning sirens go nuts

When outdoor warning sirens in Dallas cried wolf last Friday, Twitter sleuths concluded that a hacker hijacked the alarms through a vulnerable computer network. As it turns out, the sirens aren’t computerized at all — they’re controlled through a decade-old radio system, one the city just voted to spend $100,000 to upgrade. System malfunction with City of Dallas siren…