As cabin Crew, we're told (at least in my company) that this kind of device is not permitted because of the potential for interference. I can't debate the technical rights & wrongs as I don't know enough, but I do know that if I saw you with this equipment I would ask you to turn it off, and if necessary, double check with the Captain: From experience, I'd say he'd back me up.
Wouldn't it be easier (and safer) not to take it into the cabin? I see nothing but troubled times ahead if you do.