There's more cautious requirements in part III of article 800 that apply to transmitter stations. This rule is most likely meant to apply to radio stations. However, for thins like the minimum 3" separation from the building required by 810.54, there's no size of antenna that triggers this rule. Thus, a low power antenna that both transmits ad receives radio signals for the purpose of some scada control functions on a multi-building campus might be required to comply? Or is there a definition of "transmitting station" somewhere else (not in the NEC) that can help to differentiate when these rules might have been intended to apply?