Heath made air core baluns years ago. They were designed for the output of a DX-100 if I remember correctly and could be wired for 1:1 or 4:1 / 75 ohm or 300 ohm. Has anyone tried using one recently? Jerry K8JRO -- FAQ on WWW: http://www.contesting.com/FAQ/tentec Submissions: tentec@contesting.com Administrative requests: tentec-REQUEST@contesting.com Problems: owner-tentec@contesting.com