According to the database, the cars answer back on 42.32 / PL 186.2.
It takes a pretty sizable antenna to get a decent signal from the low band.
Since you appear to be near Jefferson City, you should be in the path of all the mobile relays and may be able to pick them up with an outdoor antenna. The mobile relays act as repeaters for the 42.32 frequency. The UHF frequencies use directional antennas aimed toward Jeff City. They are usually low power and could even use horizontally polarized antennas, so even their reception may be tricky. Additionally, since the relays are located to cover areas of the troop that Jeff City can't hear well, so you can expect the cars local to Jefferson City to not be heard well by the relays.
Check the Mo DPS database
for the mobile relay frequencies. Scroll about halfway down the page for Troop F. I can't verify if the information for Troop F is correct however.