Nice revival of a thread from 2003
As far as picking up MSHP.... good luck is all i can say. Sure the dispatch is no big deal, but the car to car and car to dispatch is where it gets mighty tough. You should be able to pick up the dispatch with pretty much any antenna. I also live in wentzville and can pull in the dispatch on 42.14 with the stock antenna, the RS 800mhz, the austin condor, diamond rh77ca... and thats just on my handhelds from inside my house.
The best luck i've had while mobile is with a Larsen nmo150c. I can pick up the lowband car to car and car to dispatch stuff at approximately 8-9 miles. Anything within 6 and it is crystal clear, beyond that it is staticy but still readable.
Just food for thought, i did try running a larsen nmo40c for a while and honestly didn't notice any change in performance on the lowband frequencies. The VHF-HI and UHF was totally different though. What came in clear(i.e. wentzville repeater all the way til 370 and the missouri river bridge) on the nmo150c suddenly were almost unreadable by the time i hit O'fallon with the nmo40c. If it were me i would go with a tram 5/8 wave VHF antenna(which i do have on my truck) or the Larsen nmo150c(also 5/8 wave) which i have on my car for vehicle use. Both perform the same, but one was twice as much. If you are wanting a handheld antenna get the Diamond rh77ca. NO clue what to recommend for a base setup though. I just use a RS Discone which does everything well except lowband.