FIRST OF ALL, DO NOT INSTALL AN AMP ON THE DD BOX!! Your going to save some headaches by not doing that... there are no amps out there that can switch fast enough for the DD boxes.... ask the Michigan group, been there done that, the own the shirts!
For Voice, go ahead, we added a preamp to the KJ4ACN system and that alone quadrupled our receive range!! with out the pre-amp, 15 miles mobile was about it.... NOW, we are doing better then our PORT B... with out an RF AMP... and we plan on putting in a 100 watt as soon as we find out why it hates 2 1/4 inch feed line. Evans KJ4ACN Admin www.florida-dstar.info Fla. DSTAR Tech Support