I have a relatively unique issue. I work for a company that records racing audio for multiple classes of motorsports. We do this using a set of software defined radios (SDR). We need to be able to receive broadcast between 450 - 470MHz. There is also a lot of other RF signal through out the rest of spectrum including local tv broadcast, wifi, and emergency frequencies. We currently use a hardware bandpass filter to help remove the signal out side of the 450-470MHz that we are looking for. We do not do any transmission at all, just receiving. Currently we are using an Air802 6.8dB gain omni-directional dipole antenna tuned to 450-470MHz. We are getting a fair bit of noise on all of our recordings and I am looking into changing out the antenna to see if we could get signal or at least better SNR. I was thinking that moving to a lower gain or unity antenna may help, but I'm not really sure. I wasn't sure if any one had any experience with this type of situation and could possible point me in the right direction. Thanks