Magnum Dynalab 106T with poor reception...Help

I'm in Amherst, MA, where my car radios pull in a whole slew of stations. My MD 106 T has beautiful sound to die for, but only pulls in ONE station, a strong local NPR. I added a MD whip antenna (ST-2), but all it did was add a few stations with very poor reception. Sure, I had planned on putting up a MD mast antenna outside anyway, in an attempt to get distant stations, but really, shouldn't I reasonably expect to get reception at least as good as a stock car radio?

So, is there a problem with the tuner? Ought it be sent in for occupational rehabilitation?

Also...How does one know when a tube goes bad in a tuner? Static?