The Heil mic mod is to change R55 from a 330K to a 470K resistor, and R54 from a 47K to a 22K resistor on the tx audio board. 73/DX de Rick N9THC -- FAQ on WWW: http://www.contesting.com/tentecfaq.htm Submissions: tentec@contesting.com Administrative requests: tentec-REQUEST@contesting.com Problems: owner-tentec@contesting.com Search: http://www.contesting.com/km9p/search.htm