Nope, same frequency. You might just be in a bad spot; usually folks complain the other way around (can hear the base, not the mobiles). I don't know what kind of antenna the base station uses - but I wonder if you're in a shadow caused, maybe, by the hills and such. Many such antennas would have poor near-field coverage due to the terrain.
All 39 mhz operation by MSP is strictly a simplex thing. 73s Mike