I got a GRE PSR-500 for Christmas. (My first digital scanner) I'm only having trouble trying to listening to anything on the TOPAZ RWC. I am receiving it choppy or digitized. I've tried using either Mesa Simulcast or Thompson Peak or both at the same time. I've assured that I am putting in all the site frequencies. I live in 4 story apartment building, my external antenna is outside my window.I am in direct line-of-site of both the Mesa tower and Thompson Peak. Any ideas/suggestions?