OP: Where do you live, and are you having trouble receiving the FiRST system with the stock antenna? It *should* work fine, as signal strength is fairly high on this system. An outdoor omni antenna may make things worse. A Yagi / directional antenna might work better, one you can point towards a tower site to help reject signaling from other towers that might be causing interference. Have you tried a simple wire as an antenna? Like a paper clip?