In the document after the linked one ( http://www.nsa.gov/public_info/_files/ufo/et_intelligence.pd... )

At the top: "In the most recent issue of the NSA Technical Journal-Vol. XI, No. 1- Mr. Lambrox D. Callimahos discussed certain aspects of extraterrestrial intelligence and included several messages to test the reader's ingenuity. In the following pages, Dr. H. H. Campaigne offers additional communications from outer space."

Implication is that they're just "for fun"?

Further, the NSA Journal referred to is at: http://documents.theblackvault.com/documents/nsa/extraterres...

And reads as a discussion of how ET would communicate. Received by Sputnik indeed.