How are our small car remotes able to send a signal such long distances to our vehicles?
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They broadcast with significantly more power than people expect. I have a remote rated for 3 miles in my car… of course, that’s under ideal conditions. Still, I can be deep inside a shopping mall and can still remote start the vehicle.
From a slightly technical perspective, the better remotes use a broadcast technique call Spread Spectrum Transmission. It blasts commands across a range of frequencies rather than being limited to one carrier.
The same way your little cell phone can reach up to, say, 45 miles or so in optimal conditions.
It generates a changing voltage on an antenna. The changing voltage on the antenna is radiated outwards in the air. Theres not much in air to resist these electric waves, so they travel long distances through open air.
However, things that absorb the signals drastically reduce the range. This is why having too many walls between you and the car can mean you can’t start it even from a short distance, where as being in the open air can start it far away.
This is the same as why your can can hear the radio a LONG way from radio towers, but a hill in the way or tunnel can completely cut it off sometimes.
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