Error in address below is the corrected for conical design/nasa www.nasatech.com/briefs/may01/msc22334.html. There is an e-article on construction of such an antenna. George John Drobnock The archive and Web site for our list is at http://www.meteorobs.org To stop getting all email from the 'meteorobs' lists, use our Webform: http://www.meteorobs.org/subscribe.html