Thanks to all who replied to my request. I now have two sources of the formulas as well as a "rule of thumb" formula which, being a ham, I will naturally try first! 73, Bill VE3CSK -- FAQ on WWW: http://www.contesting.com/FAQ/topband Submissions: topband@contesting.com Administrative requests: topband-REQUEST@contesting.com Problems: owner-topband@contesting.com