Not true.

Simplest way: I create a wormhole and send a signal generator through.

Not possible?

Both general relativity and quantum mechanics (our two best theories atm) suggest that wormholes are possible, possibly even fundamental. I even know how to do it since I wrote a paper on it once. Granted, I don't have the materials to make it happen and in fact the materials may not exist in our universe, but that was just according to the theories I used at the time. It is possible that one can substitute EM energy for "exotic matter" and make such topological structures out of spacetime (or the ether, or spacetime foam, or whatever you want to call it).

Another way is I could send out a few satellites and time their release to make it appear as if a single source was sending a signal from deep space.

Another way is I could control the receivers and fake the data.

I mean, there are all sorts of ways to do it. The idea that it can't be done doesn't understand what a signal is. Its just a waveform. We can create any waveform we want. It's not easy to fake a signal, but its absolutely not impossible if you have effectively unlimited resources.