Observations of the source 4C 21.53 in the frequency range 10-25 MHz .

Flux density measurements of the compound source 4C 21.53 have been obtained using the UTR-2 radio telescope at frequencies in the range 10-25 MHz. The measurements show a compact feature containing a millisecond pulsar. The flux density of the millisecond pulsar (in Jy) varies as exp -2.1 for frequencies down to 10 MHz. The spectrum of the west component of 4C 21.53 is reproduced in graphic form.