Jupiter's hectometric (HOM) wave-length radio emissions have been detected by the planetary radio astronomy instruments onboard the two Voyager spacecraft. The emission is surprisingly similar in morphology but opposite in polarization to the decametric (DAM) wavelength Jovian radio noise that has been observed with ground-based telescopes for more than two decades. The HOM emissions are predominantly left-hand polarized and their occurrence is modulated by the rotation phase of the planet but not by the location of the satellite Io. Several possible explanations for the behavior of the HOM emission are examined, but none of them are completely satisfactory.