FRIIs appear to be able to transport energy efficiently to the ends of the lobes, while FRI beams are inefficient in the sense that they radiate a significant amount of their energy away as they travel.
As FRII parecen poder transportar enerxía eficientemente aos extremos dos lobos, mentres que os raios FRI non son eficaces porque radian unha significativa cantidade da súa enerxía a medida que viaxan.