Hi! My first post, but I saw this and have been watching the site regularly. The new message is accompanied by a new Morse code message as well: cq cq cq de vt 119 sos lvl4 und attk os is dead ii sos lvl4 attk os is dead we wnt mk ie
CQ as we know is "calling any station".
de vt 119:
This I don't know. DE is Delaware, but it's probably not that. VT 119, I suspect that's probably going to be Vault 119.
sos lvl4 und attk os is dead ii sos lvl4 attk os is dead:
We know ii is repeat and as we can see, it's an SOS. OS, my best guess would be the Overseer, the person in charge of the vault. So, Vault 119 is under attack, the boss is dead.
we wnt mk ie.:
We want, they want something. Now, MK usually means mark, like a version or series of something... It can also mean "Master Key". Then again it can mean mercy killing...

ie is a little more difficult, it can mean a LOT of things. One thing that I have seen, is "Idle End", perhaps signaling that they are idling, waiting for response, maybe, maybe not. I didn't find it or MK as radio jargon.
Just an educated guess, still thinking about it.
Edit: Made correction.
Edit2: E is a dit, T is a dah (dash). we wnt mk ie, is quite possibly "We Won't Make It."
As well, the events of Fallout 3 were in 2277 and New Vegas occurred in 2281. The year for this, as suggested by the URL, is 2299. This makes me wonder, who is invading a vault???