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In: Technology
Because you can’t bury a radio antenna in the body of a steel car, but you can hide it behind plastic.
As others have pointed out, the little antenna that you see is for features that the older car didn’t even have, but that would use a stumpy antenna if you did add them. (Source: Worked for a company called Antenna Specialists that made cell phone antennas in the mid-1990s.)
The AM/FM radio in your newer car is still a long thin piece of metal but now it can be hidden within some plastic or glass part of the car, because there’s a lot more knowledge now about how to make effective antennas and also because the percentage of plastic in cars is much higher nowadays.
Essentially, it’s because the AM/FM radio antenna is hidden – much like the WiFi antenna on your phone or laptop.
In a laptop, the WiFi antenna runs [ around the perimeter of the screen](https://i.stack.imgur.com/yFAUo.jpg). This gives it a decent antenna size while remaining completely hidden. Same for your phone, if you look at pictures of old phones they all have [huge aerials](https://images.techhive.com/images/article/2015/11/old_nokia_phones-100625503-large.jpg). More modern phones still have an antenna, it’s just [hidden inside](https://www.scionlife.com/forums/attachments/tc-tech-diy-1818/102337d1501486427-shaved-relocate-hidden-antenna-dsc02184.jpg). In a car, the antenna might run around the windscreen or along the roof.
The little stump on some cars doesn’t usually hold an AM/FM antenna, it’ll be for onboard GPS, satellite, or the DAB radio.
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The same reason all the computing power used to take up a large room (look at the tech we used to send people to the moon) and now all that power is held in one hand.
As technology advances we reduce the size and also reduce the cost to manufacture it, but also make it work better as we understand it more.
Sorry for my English. I ll try to be as short as possibile since it’s in this subreddit. I think you are referring to fm am frequency, The answer is, it’s a compromise for aethetic and more import cause GPS satellite antenna need to be protected. So ideally the antenna must be the same of the wavelenght but since you can’t have 3 meter antenna even the 1/10 fraction can work. And now you also need antenna for GPS plus sometimes more satellite type. So we can do 2 things. We can use the back window of the car and hide a longer antenna around the borders that actually work better and stick the GPS in the little fin on top, or we can stick even the fm antenna inside the fin, bend it a lot and stick a rear inductant coil to try to gain more power, and be almost as good. In most case both solution are good enough. But again ideally even today, if you want to receive fm and am, best solution would be an antenna around 3 meters or ten foot on top of your car. Hope I was clear enough. Bye
Those stumpy antennas are often called Shark Fins, and they can also do satellite radio, cellular data, and GPS. For regular AM/FM radio, that antenna can be hidden elsewhere, such as embedded into a window. On my car, it’s located in the right rear side mini window.
Advancements in technology have packed a lot more function into a much stumpier antenna.
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**EDIT**
Adding a Google link to show what they look like inside …. [HERE](https://www.google.com/search?q=inside+a+shark+fin+antenna&newwindow=1&rlz=1C1GGGE___US535US535&source=lnms&tbm=isch&sa=X&ved=2ahUKEwia7Yj8wunsAhUCUt8KHRMhA9oQ_AUoAXoECAcQAw&biw=1097&bih=575&dpr=1.75)
The technology for smaller antennas is not new. Older cars simply had no need for smaller antennas – so they used FM antennas that were “regularly” sized.
There was no barrier to car makers using smaller antennas, they easily could have done so, there was just no compelling reason to.
Modern cars need to have satellite reception, these antennas are very small. Some car makers choose to also place the FM antennas inside the same “shark fin” that holds the satellite antennas. Others separate the satellite antennas from the FM and will place the FM antenna in a window or hidden elsewhere.
A long FM antenna sticking straight up in the air will perform the best, but with electronics being more sensitive today they can better receive a weaker signal than the radios of years ago. The reduced performance of the compact antennas is offset by the improved performance of the electronics in modern radios.
Aside from what others have said. Modern cars have better quality radios and signal processors that can deal with weaker signals. At the same time, car manufacturers are adjusting to changes in consumer demand.
A mast antenna produces more wind noise, and slightly more drag which impacts fuel economy. Consumers have changing views on the importance of FM and AM radios. Just like cassette tape and cd player in car has lost its importance. Bluetooth for streaming audio from a cell phone is increasingly more important.
Issues with either stationary or telescoping antennas breaking in mechanized car washes are also eliminated with a hidden antenna or reduced with a shark fin style antenna.
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