Daily Image
20-07-2007
LOFAR HBA test field
| Submitter: | Jan-Pieter de Reijer |
| Description: | An overview of the field of LOFAR High Band Antennas (HBA, 110-240 MHz), which are being tested this summer. The grey pedestal in the background is an example of a HBA "tile", which consists of a 4x4 array of dipole pairs (elements). The spider-like things in the foreground are individual dipole pairs, each on its own patch of conducting ground plane. The configuration of 6 tiles and 30 single elements has been chosen carefully for a range of tests. The response pattern of a single elements is fixed, and "looks" straight up to the zenith. But it is broad enough to "see" the sky from horizon to horizon. The signals from the 4x4 elements in a tile are combined by a "beamformer". The resulting response pattern (field-of-view) is only 15-20 degrees, depending on observing frequency, but can be pointed in different directions. Eventually, LOFAR will have around 50 HBA "stations", each consisting of up to 100 tiles. In addition, it will have the same number of stations with individual Low Band Antennas (LBA, 10-90 MHz). |
| Copyright: | ASTRON |
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