You do not say exactly where Urms and I rms are in the circuit. If this is meant to be a resonant circuit then X2 (output L) can be replaced by two Ls in parallel, one whose reactance is the same as the aerial but with the opposite sign ( i.e. +j519) and another to bring the total reactance back to +j 417. By a back of a fag packet calculation, I make this about +j2000. So this L and the series C and the remaining L, is a 1:1 matching circuit, so the 3 ohms is reflected through to the generator, this is not a good matching unit!! . I suspect your figures are correct.
Frank