( It ( ( ( ( broadcasts ( on ( the ( medium ( wave ( radio band ) ) ) ) ) ) , ) ( at ( ( a frequency ) ( of ( 1521 kHz ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ broadcasts) (PP (IN on) (NP (DT the) (JJ medium) (NN wave) (NN radio) (NN band))) (, ,) (PP (IN at) (NP (NP (DT a) (NN frequency)) (PP (IN of) (NP (CD 1521) (NN kHz)))))) (. .)))
It broadcasts on the medium wave radio band, at a frequency of 1521 kHz.
(ROOT (S (NP (NNP Am) (NN radio) (NNS waves)) (VP (VBP exist) (PRT (RP in)) (NP (DT the) (ADJP (QP (CD 540) (TO to) (CD 1600))) (NN khz) (NN frequency) (NN range))) (. .)))