Observation of radio spectral at a future radio astronomy observatory site in Indonesia.

We investigate a cascade wide-band of radio spectrum in all direction surround the Indonesian National Radio Astron-omy Observatory in Timau. A statistical method is used to quantify the threshold of the noise level in order to determine the suitable signal strength limit for the site selection of a radio quite zone (RQZ). In this paper, some important Radio Frequency Interference (RFI) sources that can potentially disturb for any future radio astronomical observations in National Timau Observatory have been identified. Based on our comparison of all the radio spectra profiles between each direction observation, we found that, two radio source are dominantly active in all direction within the frequency range around 5.2 and 5.5 GHz. Meanwhile the spectra profile that has a frequency range larger than 10 GHz are relatively silent. But, oppositely, the spectra profile of the frequency range lower than 1 GHz is fully crowded by broadcasting radio sources. [ABSTRACT FROM AUTHOR]