The Vault 88 radio beacon is a radio station in the Fallout 4 add-on Vault-Tec Workshop. It can be received after starting the quest Vault-Tec Calling, provided the player has the add-on installed and is at or above level 20. It will no longer be received after lifting the security lockdown at Vault 88.
The signal can be listened to anywhere in the Commonwealth. You can tune to it in the RADIO tab of the Pip-Boy.
After listening to the message, the location of the vault will be marked on the map and the quest Vault-Tec Calling will update.
This is an emergency broadcast signal from Vault 88. Authentication codeword IMPISH. Vault 88 emergency classification: unspecified integrity breach warning. Any available Vault-Tec personnel are required to respond under Emergency Protocol VT-76. This signal will repeat. Vault-Tec Pip-Boy signal received. Emergency broadcast ends.