SummaryThe results of further observation of Jupiter radiation, made near Sydney from June 1955 to March 1956, are presented. Most work was done at 19·6 Mc/s, but some observations were also made at 14 and 27 Mc/s.The characteristics of the 19·6 Mc/s radiation received from Jupiter are described in detail. The new facts disclosed by these observations are: (i) Jupiter radiation appeared to be random noise varying rapidly in intensity-large changes in intensity took place in times as short as 0·2 sec, but no shorter; (ii) some spaced-receiver observations indicated that the terrestrial ionosphere can have a pronounced effect on the short-term characteristics of the radiation; (iii) a single observation showed that on that occasion the radiation was circularly polarized (right-handed in radio sense).There appeared to be three sources of noise on Jupiter. None of these could be identified with visual features. The radiation emitted from the main source was confined to angles within 45 0 of a central line.The additional observations at 14 and 27 Mc/s showed that the peak intensity, mean duration, and frequency of occurrence were all greatest at 19·6 Mc/s. Two of the radio sources were active at 19·6 Mc/s but not at 27 Mc/s. The angular spread of the radiation from the principal source was considerably narrower at 27 Mc/s than at 19·6 Mc/s.The great variability and spectral concentration of the Jupiter radiation, both resembling solar noise, suggest an .origin in some form of plasma oscillation in an ionized region with a critical frequency around 20 Mc/s.