SCP-304
The Signal
Special Containment Procedures
The existence of SCP-304 is currently being masked by the constant transmissions of the ███████ space probe. This masking transmission is coded so as to prevent the deciphering of SCP-304 by any non-Foundation personnel. This transmission is in addition to the probe's publicly known communication with Earth and its conventional scientific operations conducted by NASA. The ███████ and its currently inactive replacement are on a course that will permanently keep them between the Earth and the estimated source of SCP-304. Should the original probe fail, its replacement(s) will immediately begin transmitting at the same frequency and assume all public communications as though it were the original probe.
Description
SCP-304 is a radio signal at the ██████ GHz frequency which has been transmitting a list of names and their associated titles since its discovery in 196█. The data within is a list of world leaders, which appears to be in chronological order. The signal begins in Morse Code with "King William IV" and proceeds down a list of English monarchs, American presidents and other leaders. SCP-304's format changes from Morse Code to ASCII upon reaching "President Lyndon B Johnson". SCP-304 lists a total of 63 persons with the title of "President" as well as [DATA EXPUNGED] title O5. The signal then changes from ASCII to an as-yet undeciphered format, listing an estimated 7 more names. After the 7th undeciphered name, SCP-304 pauses for 12 seconds and repeats. The reason for the abrupt conclusion of the list is unknown.
Note: The data contained in SCP-304 is restricted to O5 personnel and above. Authorized personnel confirm that the list of American and Chinese Presidents has proven accurate to date. Data which may or may not identify Foundation personnel will not be discussed in this document. SCP-304 has been determined to be coming from the direction of [REDACTED]. However, SCP-304's origin is unknown, as is how long it had existed before discovery.