Civil Alert System Broadcast is a radio signal in Fallout 4. It can be received after extending the satellites at relay tower 0BB-915.
Location
The origin of the broadcast is a ham radio in a military bunker, which can be accessed from a hatch at the base of the southwestern satellite at the Fort Hagen satellite array.
Transcript
“This is a message from the Commonwealth of Massachusetts Emergency Alert System. This morning, Saturday October 23rd, authorities detected that a nuclear attack had commenced against the United States. The following cities affected include, but are not limited to: Washington, DC; New York; Philadelphia; and Boston.
If you are receiving this emergency alert message, immediately seek shelter that can provide protection from radioactive fallout. This has been an emergency action notification.”
