I see some cars have antennas (and some even have two) and some doesn’t.
Why is that? And why some have one or two what’s the matter with the count? And wha the matter with their length and the direction they are pointing?
And what’s the fin (𓂄) doing?
In: Engineering
Many newer cars have the antenna cleverly incorporated into the wiring of the rear window demister.
The shark fin is a GPS antenna.
I find cars with extra antennas, particularly aftermarket ones centrally mounted on the roof, are often plainclothes cops.
The shark fin can be a number of things. It’s most often used as a satellite radio antenna, and sometimes a GPS antenna as well (my last two cars had shark fins but did not have GPS navigation built in). Multiple antennas are most often either ham radio folks who have rigs set up in their car or unmarked cops.
Cars usually have lots of antennas. The radio of course need a radio antenna, but each band requires a different antenna of a different length. So you have at least one FM antenna and at least one DAB antenna. You might even have one high frequency FM antenna and one low frequency FM antenna for even better reception. Modern cars usually have mobile data as well which requires antennas. And again you have several different bands each requires a separate antenna. And then you need a GPS antenna. Internally in the car you also need a bluetooth antenna. And in each wheel arch there is an antenna for the tire pressure sensor in each wheel.
There are lots of different considerations when placing an antenna. Obviously you want an antenna as high as possible and away from the car body in order to get the widest reception. So an antenna on the roof of the car is popular, often in a nice aerodynamic shell. The problem is that it does create some drag and can cause issues with roof racks and such. Cars used to have long antennas mounted on the front fender to avoid this but it have fallen out of style. You might see third party installations still do this, especially for CB as it requires a long antenna. The modern place to install an antenna is in the windscreen. Glass does not affect the radio waves the same way as the metal body so you can laminate thin films of conductive metal in the glass to work as antennas. The problem with this is that the car obscures any signal backwards, so you often see antennas in the rear window as well and might even have a radio amplifier in the rear as the wires to the front of the car can be quite long. But you still see some sort of shark fin on many cars with an antenna. And there may be some thin GPS antennas built into the roof as well.
As for third party modifications to the cars there are all sorts of things. People install third party radios, GPS, two-way radios, etc. These can come with any number of different antenna styles. Some antennas come on stickers that you place on the inside of your windscreen. Some have shark fins that you either put next to your existing or even replace the factory shark fin. And some are just a straight piece of wire that you mount anywhere on your car as long as you let it stick away from any metal.
Newer cars integrate the radio antenna into the back window. The top few lines of the defroster are actually the antenna.
The shark fin is a cell phone antenna. Any in-car apps or GPS that use data use the fin.
In most newer cars the radio antenna is integrated into the rear windshield. The sharkfin antenna can be used for multiple things such as satellite radio, GPS and cellular data. Some people will also install aftermarket antennas for CB radios.
The shark fin antenna replaces the ‘traditional’ whip antenna on many smaller cars, if it’s centred in the back. If it’s near the front and near a pillar, it’s likely a GPS receiver.
Many commercial vehicles, emergency vehicles, or radio hams will have additional communications equipment installed which uses additional antennae. These are almost always long whip antennas.
Latest Answers