I am trying to listen in, OBS, on a freq however when I put the position name and freq into the communications box and then try to select the RX, HDST, and SPKR buttons, only the RX button will be selected. When I try to select the other two I get a beep sound and a msg in the command box that reads :Error: No voice channel specified." I guess I got lucky yesterday when I was able to make it work. What am I doing wrong?