In rural areas maybe, but I highly doubt that in an area with several large buildings, that you would be able to achieve that. There is a tower about 2 miles from the Battle Creek PD station, and guess where the portables don't work? Same with the Federal Center, the hospital, and most of the schools. When worn on the belt, the body absorbs a good share of the RF energy being transmitted. They can pretty much guarantee 98% mobile coverage, but they can't come close to that with portables without a lot of BDA's or similar equipment, which of course drives up cost.