Dave, you might check your antenna I've used SmartRadio SR 161 for a year w/ nobeltec. No problems with a serial connection. Original set up was w/ a 3dB Shakespeare antenna per the instruction manual. No Joy, reception was very poor, IE limited to two miles. Tried a 6 dB antenna and reception jumped to 10-12 miles with most ships reporting off shore along the US ease coast.. Terry Haas Nima Centauri KK 4828 terry-ggtp@att.net