Why do you need an outdoor antenna like that to monitor frequencies from <20 miles away? I use a rubber duckie style antenna on my TRX-1 and I pick up stuff from multiple counties.
Also, program the EMS and fire frequencies and 95% of the time you'll always know what's going on. Seems like most calls dispatched also call for EMS and/or fire so if you've got those programmed you'll still be in the loop even if PD is encrypted.