How can DJIs drones and other competitors fly several miles away from a controller with two small antennae while retaining the signal?
In: Technology
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Simple, the signal is strong enough. Just like how you can use walkie talkie to speak with someone a lot further away. Yet you don’t see a giant antenna sticking out of a walkie talkie. There’s nothing special about the way drones transmit radio signal with the controller
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First, they use longer wavelengths. These can reach farther, because they’re not absorbed by the surroundings that well. Some wevalengths can even bounce from surfaces and the ionosphere.
On the other hand, long waves don’t provide much rate of information, but for flying a drone that’s enough.
Remember FM radio? FM were “very short waves” with good quality but short reach, while AM in the long wave ranges would reach the entire world. Same with phones, 2G were slower but good reach while fast 5G variants have small reach.
Another reason is raw power and simply better tech. More expensive manufacturers can spend more on stronger amplifiers, more sensitive receivers, better digital tech with error correction etc.
And third, drones fly in the sky so you’re more likely to have a direct line of sight. However you can still run into problems if your drone is far away and flies behind buildings or a hill.
Note, some drones don’t use direct remote control by radio, but cellular networks just like phones or your car’s GPS. In this case, distance is limited just for safety and regulatory purposes, but technically they could work anywhere.
Different kinds of signals travel different distances.
Radio isn’t like WiFi. With WiFi, you leave the house and you don’t have a signal. With radio, you can be hundreds or thousands of miles away and still get a signal. They’re using different kinds of electromagnetic radiation.
Also, there’s not only the small antenna on the drone. There’s ALSO the transmitting antenna, the source…that matters too. If it’s super powerful, then it doesn’t matter if the receiving antenna is small.
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