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Submitter: Wim Apon
Description: Mapping the radio sky with an interferometer is a wonderful hobby. As a volunteer at ASTRON-Westerbork I wondered whether I could receive radio signals from the sky at home with amateur radio equipment. After 10 years of experimenting, I managed to observe nice radio fringes at 31 MHz.

The setup consists of 2 inverted-V shaped antennas, 2 low noise antenna amplifiers, two 100-m coaxial cables, 2 home-built coherent direct conversion receivers with a weaver detector, a normal PC with a sound card digitizer and a lot of home-written software.

The aerial photograph shows a fixed antenna in the corner of the field and a moving antenna on the "astro-rover", while the bottom right inset shows the receivers. I make 24-hour observations, which typically gives fringes like the one in the top right inset.

Every day, I put the astro-rover at a different position following a rectangular grid. A 2D-FFt of the measured visibilities results in a map of the sky. For the latest results, visit http://home.kpn.nl/apon001/huis.htm
Copyright: Wim Apon
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