hello guys, the schematic came from the latest ON4UN handbook. it is the high pass filter as shown on page 3-13, designed by W3NQN. it really works. good luck. larry, n7dd -- FAQ on WWW: http://www.contesting.com/topband.html Submissions: topband@contesting.com Administrative requests: topband-REQUEST@contesting.com Problems: owner-topband@contesting.com