I recommend the RTL-SDR dongles from the link below:
Buy RTL-SDR Dongles (RTL2832U) - rtl-sdr.com
RTL-SDR Blog R820T2 RTL2832U 1PPM TCXO SMA Software Defined Radio with 2x Telescopic Antennas
or
RTL-SDR Blog R820T2 RTL2832U 1PPM TCXO SMA Software Defined Radio (Dongle Only) if you are going to use an outdoor antenna. If so, you will need to also order the appropriate pigtail or adapter. I would find another source for the adapters or pigtails so you can order what you need instead of the kit that contains adapters you may never use. With a quick Google search you should be able to find a source for those.
I own both the NooElec and the RTL-SDR dongles and have had much better luck with frequency stability/drift when using the RTL-SDR brand.
However, you first need to determine if you local departments are encrypted or not. If they are encrypted you will not be able to listen to their traffic. Provide location information and department/agency names to get help with that.