What is the best antenna besides the duck to use with my Whistler TRX-1? I have a Diamond RH77CA I was using on my old Radio Shack digital scanner. It seems to pick up more on the RS then when I hook it up to the Whistler. When I go to railfan, I hear trains further away with the RS and the Diamond then with the Whistler and the Diamond. I'm concerned because I paid good money for the Whistler and want to get the best possible.