Frequency Characteristics of Atmospheric Noise at New Delhi

Frequency characteristics for the atmospheric burst noise data collected at New Delhi show large variations of the order of ± 6 dB within the time block 16.00-20.00 h, particularly in the frequency range 1.0 to 10.0 MHz. Similar variations are obtained for the data culled by the ARN-2 recorder developed by the NBS (National Bureau of Standards) U. S. A. It suggests that treating atmospheric noise on the time block basis as done is worldwide noise predictions furnished by CCIR (International Radio Consultative Committee), at least for the frequency range 1.0 to 10.0 MHz and the time block 16.00-20.00 h would result in large errors.