Detection range of mobile p25 radios

Clearly our hobby is making 0 progress toward decrypting even the most simple of encryption algorithms at least publicly anyhow. In light of this does anyone out there recommend some kind of device to increase the range of close call to let's say a mile or so. This would at least indicate the presence of these radios. Do P 25 radios signal back to the tower every few minutes? This transmission could also indicate the presence of these radios in one's vicinity. Clearly in a rural or wilderness environment being able to pick up any transmission in the 700 MHz band would indicate at least the presence of someone of a government nature. Also anyone who could give out any reccomendations with regard to radio direction finding and traffic analysis would be greatly appreciated.