https://play.google.com/store/apps/details?id=marto.androsdr2, which when combined with the following RTL2832U driver: https://play.google.com/store/apps/details?id=marto.rtl_tcp_andro, USB OTG cable: http://www.ebay.com.au/itm/USB-OTG-USB-Cable-Adapter-for-Samsung-Galaxy-S-3-S-III-i9300-S2-i9100-/310422121131 and USB TV dongle: http://www.ebay.com.au/itm/DVB-T-T-Stick-SDR-FM-DAB-Tuner-Receiver-Stick-Realtek-RTL2832U-E4000-/370677800882 you can have a portable radio scanner! The USB TV dongle I linked to should get a working range from 50MHz to 2200 MHz (200 MHz shy of 2.4GHz). But you could always get an upconverter to play with (such as the Ham It Up).
It should work, from my understanding, but I'm just going to have to test it out! =3
The only drawback for those out there with older Android phones is that it needs a rooted phone if your version of Android is older than 3.1, but for those of us with newer phones running newer versions then we're all set =D You'll also probably need to run a powered USB hub to supply the TV dongle with power, but you should be able to hook the hub up to a battery pack thus still making it all portable =D