Tri-Ex rates thiers at 70mph and provides calculations for that speed. For "comparision purposes only" they provide a chart for 50mph. 73, Jim, WA6SDM jholly@cup.hp.com -- FAQ on WWW: http://www.contesting.com/towertalkfaq.html Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: K7LXC@contesting.com Sponsored by Akorn Access, Inc & KM9P