The video receiver (VRx) of the FPV drone is the key part of the FPV system! The UAV equipped with the first person view (FPV) system usually has a small and simple camera in front of it. The video signal from the camera is sent to the video transmitter, where it is formatted, amplified and broadcast. Without a video receiver on the ground, the video information provided by the UAV will be useless. As the name suggests, the function of the video receiver is to receive radio frequency (RF) waves carrying video / audio information from the UAV and convert them into usable video signals for display in your goggles. At the basic level, the working principle of the video receiver is very similar to that of the video transmitter, but the opposite is true. The RF video signal of UAV is received by receiving antenna. It’s amplified and formatted by the receiver and sent to the goggles, all at incredible speed! Although there are digital and analog FPV systems to choose from, in this article we will focus on analog systems. Although the price of digital systems has declined and their performance is improving, analog systems are still the most widely used systems.
Singular and diversity modules
The simplest FPV drone video receiver has a receiving module and needs an antenna. However, for the best RF video reception, it has been found that using two separate receiving modules working together, called diversity, has the best performance. These receivers actually have two receiver modules, each with its own antenna. The logic board will select the best video signal from the two modules according to the signal strength and send it to the goggles. The switching between the receiving modules is very fast and there is no fault, so the video receiver always provides the best video signal for the pilot. In general, the diversity system will have a single omni-directional antenna and another antenna which is usually a directional antenna.
Video receiving frequency of FPV drone
For racing cars and freestyle UAVs, the best frequency for video transmission is 5.8 GHz. In the United States, this is one of the radio frequency bands classified by ISM (industrial, scientific and medical) of the Federal Communications Commission (FCC). These frequencies can be provided to users with free license of power levels for general UAV operation. The 5.8 GHz frequency allows the use of smaller antennas, has a good range, and can carry relatively high-resolution video signals. There are other frequencies available for video transmission, such as 2.4 GHz, 1.3 GHz, and 900 MHz, however, based on the size of racing cars and freestyle drones, the 5.8 GHz band has proven to be the best fit. So when building or buying your UAV, be sure to match the frequency of your video transmitter to your video receiver.
At 5. Within 8 GHz, we actually used a frequency range from 5. Three gigahertz to five. 9 GHz. Band 5.8 is divided into “channels”. For example, “race band” has eight channels, the lowest channel is 5658 MHz, the highest channel is 5917 MHz, and the interval is 37 MHz. This has been optimized to allow up to eight pilots to fly simultaneously under ideal conditions. When competing or flying with friends, it’s better to choose the channel as far away from each other as possible, so as to minimize the video interference between UAVs. The current video transmitter and video receiver generally have at least 40 total channels, each channel has at least 5 channels, such as race band, each channel has at least 8 channels.
Types of FPV drone video receivers
The video receiver can be mounted on a tripod and the goggles are connected to the receiver with an A / V cable. Instead, video receivers have been shrinking in recent years, allowing for the integration of diverse systems into modules that can be installed on goggles. For long-distance FPV, it is usually better to install the video receiver on the tripod, so that the more distant directional antenna can point to the aircraft. For racing cars and freestyle, however, pilots have achieved great success with goggle based modules. Some video receivers also have additional features, such as automatically scanning the RF noise floor or channels already in use around you. They may also have channel memories that can quickly switch between two or more favorite channels. While these options are convenient, they are unnecessary on first boot, and these devices often have the same video sensitivity and clarity as simpler and cheaper devices.
