While appearing as a straightforward and sensible inquiry, the question of a drone’s range is more complicated than it first seems. Due to issues ranging from legality to the type of transmitter your controller has, there is a myriad of things to consider before a conclusive answer could be reached.
To further complicate the matter, it has been seen that in a lot of cases, the range of the drone that is advertised by the manufacturer turns out to be plain wrong. Thus, in this article, we will take a general overview of all the factors we need to observe when answering that question.
A general answer to the question is to give the 10km figure, but this comes with so much caveat that it’s worth delving deeper.
The concept of the range of a drone has two major parts. The first is the length of time the drone can spend flying on a set of fully charged batteries. Also referred to as the flight time of the drone, this is determined by how good the batteries are.
The second part to consider is the maximum distance the drone can be from the controller and still retain the communication between itself and the flyer. Assuming that there is a clear, unobstructed path between the drone and the controller, this distance depends on the quality of the transmitters on the device.
Because this issue is sensitive to be misunderstood, great care should be paid. On the official websites of manufacturers like DJI, the figures stated are astonishing.
Taking Mavic 3 as an example, on DJI’s ‘Specs’ page for that model, it is stated that the maximum flight distance is 30 km. This only means that the Mavic 3’s transmission system can communicate with the controller at that distance.
It does not take into account the battery life and restrictions put in place by officials. Assuming that the battery can get the drone to the 30 km mark, the return journey for the drone is a concern real-life users face.
Therefore, when talking about the range, the idea that the batteries have to support the drone on the return journey should be kept in mind. Another thing to consider is the regulations.
Because of FCC and CE regulations, there is an upper limit to how strong the signal the drone and its controller can emit. This means that however better the transmission technology gets, there will be a firm legal upper limit. That is why 10 km is the general limit to the newest range.
The variance in the factors being this large demonstrates that to answer how far drones can fly, a much deeper examination is needed — starting with the legal aspect.
VLOS — Visual Line of Sight — is a very important thing to always keep in mind. The FAA states that ‘recreational flyers should keep drones within the visual line of sight [VLOS] or use a visual observer who is co-located (physically next to) and in direct communication with you.’ Given that this rule was meant to avert drones from either entering zones they’re not supposed to or accidentally crashing into structures, it should be observed seriously.
Factors Affecting Range
At the most basic level, how far a drone can go is determined by how strong the radio transmitters (devices that send radio signals to communicate commands wirelessly to the drone) and receivers (devices on the drone that wirelessly receive radio signals from the controller) are.
A very superficial guiding rule of thumb for determining how powerful the transmitter/receiver is when considering a drone is to look at the price tag. Unsurprisingly, the pricier the drone, the more likely the transmitter/receiver will be of better quality.
The type of information that is shared between these devices can be put into two categories: the video signal and the control signal. It is because these two signals are broadcast through different frequencies that the video almost always cuts off first before the person loses control over their drone when the drone goes too far away.
The electromagnetic signal that drones and their controllers use is radio frequency. This means that it is susceptible to a wide range of interferences. The most important factor that massively limits transmission is physical blockage or obstruction.
If there is an object large enough to interfere with the signal that is located between the controller and the drone, the total range of the drone could be limited. Another problem radio frequencies face is reflection. Surfaces that reflect radio frequency — like a cement or roof surface — can result in multiple paths the frequency will take between the antennas.
Apart from these, radio frequencies can also suffer challenges from stormy weather, although a lot of transmitters that operate at and above 2.4GHz penetrate rain easily.
Battery Life Concerns
Flight time is the other major determinant of how far a drone can fly. Generally speaking: the better the battery, the longer the flight time. How good the battery is depends on many things, but the biggest factor is the type of the battery itself.
Lithium-ion Polymer batteries (LiPo) dominate the drone battery industry — for a reason. Because of the very light properties of the metal, Lithium battery types are ideal for situations where weight is an issue.
LiPo batteries are a subset of these Lithium batteries, and because they use polymers instead of liquids as their electrolyte, they pack in way more specific energy. Therefore, it is fairly rare to see other types like Nickle Metal Hydride batteries in employment.
Regardless of how good the battery is, though, the drone’s flight time might still be impeded by the amount of weight the batteries have to support during the flight. If the drone is on the heavier end, the flight time will be perceptibly lower because the propellers need to expend more energy during the flight.
Additional devices and other materials like floatation devices, guards, cameras, etc. that have been attached to the drone will also affect the flight time because they will increase the overall weight of the drone.
The environment also plays a role in flight time. If it is a very cold day when flying the drone, it may be noticed that the flight time will be shorter.
This is because LiPo batteries discharge inefficiently in colder temperatures. It is when the temperature drops below ten degrees celsius (fifty degrees Fahrenheit) that the issues with the performance will be very apparent, and when it is below minus seven degrees celsius (nineteen degrees Fahrenheit), the issues will be too serious to be ignored.
The flyers’ decisions are the other factors. Continuously flying against the wind direction, especially if it is a particularly heavy wind, can drain the batteries faster.
Aggressive maneuvers and high speeds during flying, too, will reduce flight time. Battery care habits are also very important. Optimal temperature, voltage, and right chargers should always be maintained while charging.
How to Increase the Range of Drones
Whichever method it is that you’ve decided to use to improve the range of your drone, the most obvious first step should always be to make sure all the parts of the equipment are fully functional. This also includes making sure that the connection channels that the drone and the controller are tuned properly.
Before trying to extend the range of drones, the most logical first step is to make sure the conditions are optimal for the signal to transfer. Powerlines, routers in buildings, etc. produce their own radio frequency signal that interferes with the drone signal, so it’s always better to fly drones away from them.
Similarly, buildings, trees, mountains, etc. along with bad weather conditions (fog, storms) will obstruct the path between the controller and the range. The ideal condition is flying on a grassy plain far from urban areas on a sunny day.
The next step is to be aware of the directionality of the controller. If you have an omnidirectional antenna on your controller, that means you don’t have to worry too much about where your controller is pointing as the signal, centered at the antennas, propagates in a spherical manner.
What directional freedom such controllers give is paid for by their relatively limited ranges. Conversely, if you have a directional controller, it needs to be pointed in the general direction of the drone to transmit efficiently.
While this entails that the person flying the drone needs to be consciously following the drone to point the controller at it, because the signal is focused and there is less wasted energy, the range such controllers allow is pretty impressive.
Finally, range extenders — devices that physically increase the strength of the signal — can be used. For the average user, range extenders called parabolic reflectors are usually enough.
Parabolic reflectors are very simple devices: sheets of reflective metal concavely cover the inside of plastic cups. They work by reflecting the signals that are propagating away from the drone back toward its location.
This technically means that omnidirectional controllers equipped with parabolic reflectors become directional controllers. Because they are very simple devices, they offer the added benefit of being extremely cheap to buy and install.
The other types of range extenders are called signal boosters. Usually using the Yagi Uda antennas, these are far more effective in increasing the range of drones. Being very fairly priced and almost as easy to install as parabolic reflectors, these extenders are also very good options.
If what these antenna extensions offer isn’t good enough, you can always go for buying the full-on DJI-made extenders (BlueProton DJI Phantom 4 & 3, for instance). Even though these cost far more than the simple parabolic extenders and Yagi Uda antennas, for flyers that are serious about having huge ranges, this option is viable.