http://www.trevormarshall.com/waveguides.htm also discusses the problems inherent with waveguide designs, a good read. -Drew -- To unsubscribe, send mail to minordomo at wireless.org.au with a subject of 'unsubscribe melbwireless' Archive at: http://www.wireless.org.au/cgi-bin/minorweb.pl?A=LIST&L=melbwireless IRC at: au.austnet.org #melb-wireless