What Frequencies Do Drones Use?

David Lemay02 Feb 2023

Drones, like other digitally connected devices, emit and receive signals over a specific radio frequency. One frequency band might offer significantly greater performance than the other depending on where the drone is being operated.

What Radio Frequencies Do Drones Use?

The 900 MHz band is used frequently by RC (remote control) drones that don't send video back to the ground. This frequency range is found in the UHF range. The first users of the 900 MHz spectrum were those in the industrial, scientific and medical sectors.  Amateur radio stations also made advantage of the spectrum. Amateurs, however, must tolerate interference from ISM devices and cannot generate interference themselves.

The 27 MHz and 49 MHz frequency ranges were used by some of the earliest toy drones. Toy RC cars normally can't run on the same 27 MHz or 49 MHz bands simultaneously due to the increased risk of interference caused by the narrower frequency bands.

There is no chance of crossover between devices in a dwelling if they all use their own unique radio frequencies. For instance, AM radio signals are transmitted between 535 kHz and 1.7 MHz.

Manufacturers increasingly rely on the 900 MHz frequency as drones' complexity increases. This increased bandwidth is possible because of the higher frequency that can be used by electronic equipment. It also offers the ability to go through obstacles.

In many earlier designs of drones, the camera was permanently installed and data was stored onboard the aircraft. Consumers can transfer the media files to a personal computer or notebook after retrieving the drone.

Manufacturers began utilizing greater ranges of frequencies after the introduction of video-controlled drones. Data transfer rates in the 900 MHz spectrum are insufficient for broadcasting video into the subfloor.

The 2.4 GHz and 5.8 GHz frequency bands are commonly used by video-controlled drones, also known as first-person-view (FPV) and remote-person-view (RPV) drones.

The data rate at which higher frequencies transmit is higher, but the distance they can travel is much shorter. Due to the limited range of such wavelengths, communication between the receiver and drone is hindered by obstructions such as buildings.

Modern wireless communication equipment, such as home Wi-Fi networks, can also use the 2.4 GHz and 5.8 GHz frequency bands. Drone pilots using the entire 2.4 GHz or 5.8 GHz frequency bands in a residential neighborhood are more likely to experience interference.

What Frequency Do Drones Fly On?

Drones use certain radio frequencies, or "bands," for their communications. Radio waves, which are undetectable on the spectrum and are quantified in terms of hertz, are a type of electromagnetic radiation. The technology uses frequencies from the low hundreds of hertz to the high hundreds of gigahertz. The use of a transmitter and a receiver is essential in most forms of radio communication.

With radio waves and a predetermined frequency, the transmitter may send and receive data. The transmission will only work if the transmitter and receiver are both set within the same frequency range. When controlling a drone, both the remote control and the drone itself serve as transmitters and receivers.

Frequency identification (RFID) tags are also commonly used to fine-tune transmitters and receivers. To avoid interference from other devices, it aids in matching the transmitter and receiver to the same frequency.

The 2.4GHz Frequency Spectrum

The maximum range for a 2.4 GHz band drone is typically between 1.6 and 6.4 kilometres. However, direct line-of-sight is necessary for radio waves (LOS).

There can be no effective communication between the devices unless there is a direct line of sight between both the transmitter and the receiver. Drones operating on the 2.4 GHz band may experience interference when flying through densely populated urban areas due to the presence of several nearby buildings, residences, and Wi-Fi electronics.

Numerous drones come with low-cost antennae that boost the signal by 2 decibels, allowing them to travel farther. Drone pilots might also be prepared to upgrade an antenna to receive additional power, allowing them to fly further with their gadgets. Drones with stronger antennas may maintain broadcasts on the 2.4 GHz or 5.8 GHz bands for as far as 6.4 kilometres.

Drones operating at 900 MHz have a far greater range. The maximum range of a 900 MHz signal is around 20 miles. Drones operating in the 900 MHz spectrum have one major drawback: they can't always transmit live video.

How To Detect Drone Frequency

Drone frequency can be detected using an RF sensor. To function, an RF sensor simply listens for signals in the radio frequency ranges used by drones to communicate with their operator. 2.4 GHz and 5.8 GHz are the most often used frequency ranges for drones. Numerous drones, notably those manufactured by DJI, operate on these frequencies. Additionally, the 1.2 GHz and 1.3 GHz bands are employed in the drone sector for transmissions between the drone and its controller.

An RF sensor is a passive radio frequency receiver that monitors these frequencies. In order to determine the source of the signals coming from a drone and its controller, it first looks for a communication protocol and then compares that to a library of known communication protocols.

RF Communication Protocol

The exchange of data between a drone and its controller is facilitated by an RF Communication Protocol, which is a set of rules for how these packets should be formatted and transmitted. A drone's operator sends instructions for the drone's flight path (right, left, etc.) using the protocol. Further, the protocol is used to transmit a wide variety of encoded data types. Real-time video, the drone's GPS coordinates, altitude, speed, and any other data that may be termed flight telemetry, are all being transmitted and received in real-time over the radio frequency spectrum.

2 Types of RF Sensors

Drone detection RF sensors can be categorized into two groups. Both are receptive receivers of the RF signals being transmitted.

The first one is the protocol decoder, which allows you to see all the information passing back and forth. This sensor decodes and reads the protocol to provide accurate GPS coordinates, altitude, and speed.

The second kind of radio frequency (RF) detector can determine the communication protocol's typical behavior. This sensor keeps track of all the different drone types and their RF signatures in a large database (often acquired through testing). The sensor can determine what kind of drone is transmitting based on its unique signature, which is compared to a database of known RF drone communication patterns.

Drones can be used for hours of fun and have useful applications in various fields, but they can also be utilized in dangerous ways if not used responsibly. Thus it can be valuable to monitor the radio frequency environment to detect the presence of a drone.

David Lemay

David Lemay

I'm David Lemay, a lover of tech and have had an interest in drones for years. Bought my first few drones, before I started building my own. I want to share my passion with others, so I started this site to help others who want to get into the hobby.

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