Measurements of radio noise at 0.700 mc and 2.200 mc from a high-altitude rocket probe

Radio noise observations at frequencies of 0·700 Mc and 2·200 Mc were made at altitudes between 3000 and 11,000 km from a Blue Scout Jr. high-altitude rocket probe on 30 July 1963. A steady background flux of (7·5_?3⁺⁶) × 10^?19 W m^?2)(c/s)^?1 at 0·700 Mc and (1·8^+1.0_?0.5 × 10^?19 W m^?2 (c/s)^?1 at 2·200 Mc was observed. Assuming a galactic origin of the observed fluxes at both frequencies, the averaged sky brightnesses are b(0·700 Mc) = (6_?3⁺⁵) × 10^?20 W m^?2 (c/s)^?1 sr^?1b(2·200 Mc) = (1.4^+1.0_?0.5 × 10^?20 W m^?2 (c/s)^?1 sr^?1 The observed brightness at 2·200 Mc is in reasonable agreement with the results of other observers. The apparent brightness at 0·700 Mc is, however, greater than was expected from previous observations. An alternative source of the 0·700 Mc flux in the terrestrial exosphere, as well as characteristics of several noise bursts observed during the flight, is briefly discussed.