commercial uhf antenna

Hi Folks, I'm in need of a UHF base vertical antenna that covers around 415 MHz or 455 MHz. Gain should be 5+ dB. I was wondering what antennas do public safety agencies use. Any idea would be appreciated. I came across Antenex @ FG4505 Antenex Laird UHF Fiberglass Omnidirectional Antenna but...