Sky modeling for correction and calibration of a single VHF antenna system for interferences monitoring

Abstract

Using a VHF dipole antenna built for the 10-100MHz band and used for RFI monitoring of the Nancay radioastronomy station site, we investigate the influence of the sky signal on the observed power. The latter is seen as a power modulation at a period of one sideral day in long term monitoring data. By use of a sky and antenna model, a simulated receiver temperature due to sky only is estimated. That model fits the time modulation very well and is used it fot excision of the sky signal and calibration of the power scale in Kelvin units. An example application of calibration and correction is shown on an observed spectrum.