Hi Don, Tony is correct, For H-68, AO51 and ISS you do not need a pre-amp. As an example how AO51 via a simple antenna + THD7 sounds: http://www.pa3guo.com/holiday_2006.html Henk, PA3GUO >If you are standing outside with your arrow, a short >feedline and an HT, you will not need a preamp. > >73, >Tony AA2TX