Originally Posted by ROBDOG1
What if I just cut with some metal cutters and plasti dip ?
Antennas are tuned (and averaged) for a specific frequency or range of frequencies.
Cutting a stock antenna isn't a good idea because you're eliminating that "tune". While you may not notice because you listen (for example) to a lot of stations in the lower range, when you try to go to the upper range, it'll have poor reception. This is the BASIC idea and there's a reason that happens.
Here's some more info that may put it into perspective. Optimally, FM antenna would be somewhere around 120 inches long. Pretty ridiculous to see vehicles with 10 foot antennas on them right? Automobiles run a "quarter wave" antenna. Quarter wave is basically one quarter scale of what a full size antenna would be.
With a quarter wave, the low end of the FM scale would be someplace around 26.5 inches in length. This would be the "optimal" length to receive lower frequencies in the FM range. Mid scale is about 30 inches, upper end is about 33 inches. I believe most auto manufacturers use something about 30 inches (do the math - it's "one quarter" of 120 inches). My lengths may be off a little here or there - I'm drawing on my college electronics/RF experience and that was LONG AGO
, but this gives the general idea.
A stubby antenna typically contains a "tuned coil" or "load" somewhere internally. This load could be in the base, it could be engineered into the overall length of the antenna, but somewhere this antenna is "tuned" and this makes the antenna "electrically" the ideal length. Ever see a CB antenna was a "lump" in the middle of the mast? Same idea - they're trying to reach optimum "electrical length" in a shorter package. (Completely different frequency range, but the same theory holds true.)
With a stubby antenna, some experience signal loss and poor reception, some don't. Honestly, there shouldn't be an issue if the "stubby" is tuned properly but a lot of radio reception depends on terrain, how well the receiver is tuned, how well the transmitter is transmitting, condition of antenna cable, etc.
Technically, there is no need for a stick (mast) antenna at all as long as ELECTRICALLY you have the ideal length of "antenna" and it's relatively unobstructed. A lot of newer (foreign) cars don't even have an antenna that is exposed - it's engineered into the front or back (sometimes, both) glass.
We won't even get into "HD" digital radio as that is a whole other kettle of fish.
The theory above is drawing on my experience with good old fashioned ANALOG radio. With HD/digital radio, there is no "poor" reception - you either have reception or you don't.
Sorry for the short dissertation, but I thought all of this may be useful for those just wanting to cut their stock antenna.