Cosmic radio-noise intensities below 10 Mc/s

The results of observations of cosmic noise at frequencies of 10.05, 5.65; 4.4, and 3.8 Mc/s are reported. At the three highest frequencies, half-wave dipole aerials were used, while at 3.8 Mc/s the aerial system was an array with a beam-width of 50° by 26°. In addition, previous observations at 2.13, 1.43, and 0.9 Mc/s have been reassessed. It was found that the increase in the intensity of the radiation with decreasing frequency ceases at about 10 Mc/s, and that the spectrum is flat between 10 Mc/s and 2 Mc/s, and possibly to 0.9 Mc/s. The flux density of the radiation at these frequencies is approximately 2×10−19 watt/m2 (c/s)−1, the equivalent temperatures varying from 6×105 degrees at 10 Mc/s to 3×107 degrees at 0.9 Mc/s.