[It's a fortunate thing that Una reads quickly, because Narvin reaches over to take the communicator from Una, without bothering to (or thinking of) asking first.]

Hmm. Some sort of energy field from the sounds of things. Something that allows the long wavelengths of low frequency radio through, also presumably infrared or else the place would quickly begin to freeze over until it looked like the surface of Pluto, and visible light. But it doesn't allow the high frequency radio waves of the hand held communicators through, which is very interesting. Perhaps the dome is operating near a similar frequency, cancelling it out.

[Narvin's expression remains merely curious. His voice mild. It's still just an intellectual exercise to him. Without seeing the suffering, it's like any report an operative might bring to his desk about alien wars or disasters.]