I would recommend Compliance Engineering magazine, and specifically the annual Reference Guide issue, as a good starting point. Call 978-635-8580 for a free subscription qualification form, or www.ce-mag.com from your question, I assume that you don't have your own testing lab, so I would also recommend starting a relationship with your local contract test lab. If you are using them (and paying them!) for the actual certification testing, they will usually be very helpful "off line" to prevent trouble on new designs. ------------ Barry King, KA1NLH Engineering Manager NRG Systems "Measuring the Wind's Energy" Hinesburg, Vermont, USA barry@nrgsystems.com "The witty saying has been deleted due to limited EPROM space"