Rita hasn't been with us for quite some time. Some say she was banned. I don't believe it. My guess is she's been taken on board the Mother Ship where, unfortunately, AM radio reception is just terrible. Golly, I miss her.
The petavolt-per-meter 5th dimensional field inside their antimatter reactors kills all reception of 3-dimensional electromagnetic propagation.
The aliens themselves use nothing but sub-ether for that reason. We Earthlings, sadly, do not yet have that technology.