1. School of Electrical Engineering; KTH Royal Institute of Technology; Stockholm Sweden
2. Southwest Research Institute; San Antonio Texas USA
3. Institute of Geophysics and Meteorology; University of Cologne; Cologne Germany
4. Department of Earth and Planetary Science; The Johns Hopkins University; Baltimore Maryland USA
5. Department of Physics and Astronomy; The Johns Hopkins University; Baltimore Maryland USA
6. SETI Institute; Mountain View California USA
7. Southwest Research Institute; Boulder Colorado USA