So, at the battle for the dam, I was listening to the NCR radio transmissions and a couple of times they said that they were receiving help from non-NCR people.

The thing is I turned all of the factions except the Khans to Caesar, and I never saw anyone but NCR during the battle.

Does anyone know what it was referencing?

It's supposed to be referencing the player (you) as far as I'm aware. I guess the developers just didn't expect you to tune in to the channel when you side with Ceaser, and didn't bother to change it or turn it off.

Interesting. When I did the NCR path, I don't recall seeing the notice that I could get that station. I thought it was only for the Caesar path.

That makes sense, though.