Hi all,
I wouldn't be so harsh as to say "trash it", rather I would say to give it a merciful lethal injecton of sulfuric acid and bury it in the back yard. At best a through glass antenna is horribly inefficient and you get more signal off the coax than the antenna itself it's that badly mismatched. Then trying to find the sweet spot which is not always when the sides are aligned is impossible without a wavemeter or analyzer, ask a professional cell phone installer or ham operator who has ever used one for 2M.
Mobile public service receivers may be legal in Canada but illegal in the US without a permit. You have to demonstrate a need to get one like being an EMT, fireman, policeman or other person involved with public service work. Then in places like Rochester NY they have new laws on the books that as written outlaw mobile ham equipment as well, try showing your permit or ham license to one of those cops and see if it keeps you out of trouble, not. You'll have to take your chances with the judge who always sides with the cops and take it up through the appelate court and higher, spending your hard earned cash on legal fees as you go. Leave the scanners at home and save yourselves the trouble.
BTW, your car looks better without an antenna on it too unless...
If you have an old beat up pickup truck with a 102" CB whip on it, a gun rack and a blue tick hound in the back,
you might be a redneck.