Dear Ricardo, I strongly recommend this web site of Reg Edwards. He has everything anyone could ever want regarding antennae and transmission line formulae in the form of simple computer programs that work! And ALL FREE! http://www.btinternet.com/~g4fgq.regp/ I did not try to figure out which specific program would do the job on your question, but if you spend a couple of hours downloading ALL of them, they will be worth the effort. All the best. 73 de W9DMK - Bob Lay, Dahlgren, VA http://www.zaffora.com/W9DMK/W9dmk.html w9dmk at crosslink.net