Joe ,if youre itchin to build one look at this copy of a patent . If I can post it .. Hope you got high speed though . Ivan http://www.freepatentsonline.com/pdf_collections_server1/uspt/patent_pdf/5848/US5848715/pdf/US5848715.pdf?k=cb8a0ec97a60c14ee5adb77690a5263e