Advances in Radio Science www.adv-radio-sci.net 1684-9965 1684-9973 1 Kleinheubacher Berichte 2002 2003 10.5194/ars-1-329-2003 http://www.adv-radio-sci.net/1/329/2003/ http://www.adv-radio-sci.net/1/329/2003/ars-1-329-2003.html http://www.adv-radio-sci.net/1/329/2003/ars-1-329-2003.pdf 329 333 2003-05-05 Response of the Effelsberg 100m radio telescope to signals in the near-field at 24 GHz K. Ruf E. Fürst K. Grypstra J. Neidhöfer M. Schumacher Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53111 Bonn Short range radar (SRR) for cars has been proposed to operate over 5 GHz of bandwidth at the 24 GHz ISM band. To estimate the level of interference from these devices on radio telescopes, the near-field antenna pattern has to be known. We report on new measurements with the Effelsberg 100 m radio telescope. These measurements were performed with a transmitter set up at a distance of 1.7 km from the telescope. The strength of the signal picked up by the telescope sidelobes shows that the proposed SRR would interfere with sensitive radio astronomical observations.