Daily Image
02-09-2009
HBA First Light at Effelsberg
| Submitter: | James M Anderson |
| Description: | The Effelsberg LOFAR high-band system (HBA) has finally seen first light. After a long delay caused by vacations of people at Effelsberg and Dwingeloo, and scheduling conflicts with ongoing pulsar observations, TBB tests, and imaging observations, the tiles have been connected to the station electronics. Photons have been received by the antennas, voltages amplified and sent down the cables, and measured by the receiver units in the Effelsberg LOFAR station. This picture shows a spectrum plot integrating over 1 s of time for tile number 0 in the array. The HBA is in RCU mode 5, which means that it has a bandpass transmission from 110 MHz to 190 MHz. The spectrum is undersampled by a 200 MHz clock. The bandpass filter and the undersampling mean that we are looking at the second Nyquist zone, and in spite of the frequency labeling in the plot, the frequency runs from 100 MHz on the right-hand side, to 200 MHz on the left-hand side. RFI from the FM radio band can be seen on the far right, and the general sky brightness can be seen from 110 to 190 MHz. Some RFI appears at about 134 and 137 MHz. This achievement was made possible by cooperative work between the Bonn/Effelsberg LOFAR group and the ASTRON LOFAR group, working out many issues to get things to work. Congratulations to everyone. After some more system verification, we hope to make an all-sky map with the Effelsberg HBA system in the near future. |
| Copyright: | Max Planck Institut fuer Radioastronomie/James M Anderson |
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