FPV for dummies. All you need to know about FPV Racing Drones.
Every day the acronym FPV is becoming more and more popular among the RC hobbyist community and the public in general. We have prepared this article to explain in detail what FPV is, what the elements are necessary to create your own FPV system, how to set them up and finally some tips to improve your FPV experience.
1. What is FPV?
FPV is the action of controlling a UAV (Unmanned Ariel Vehicle) through live stream video relayed by a camera on board to a ground station monitor device. FPV stands for First Person View and is the closest sensation to being a real pilot. Lately Youtube is flooded with thousands of videos of aircrafts flying at high speeds through a forest or an abandoned building, reminding us of the sci-fi movies and video games that we like a lot.
It is not a simple hobby anymore, with the rapidly growing amount of people that are flying FPV this activity has turned into an organized sport with many official leagues created around the world.
FPV suits almost everyone regardless if you like fast racing style or relaxed aerial filming which carries certain benefits like more precise control, more agile flying, going further and higher.
2. Build your own or buy it ready to fly?
The answer for this question depends on your electrical skills and understanding of the theory behind the system. If you don't feel comfortable with your soldering skills or don't have enough time, you can also try a ready to fly option like the Walkera Runner 250 FPV
3. FPV main components
A basic FPV system consist of:
- The camera
- The transmitter (Tx)
- The Video receiver (Rx)
- A video display device.
The camera must be positioned in the front of the aircraft to achieve that feeling of being on board and depending on how fast you like to fly you will have to adjust the angle of the camera, otherwise it will be pointing to the ground. It is good to start with the camera straight forward, then increase the angle to 10 - 15 degrees for an intermediate speed level and 30 degrees and up for an advanced speed level. The video transmitter sends the wireless signal to a ground station receiver and provides video that you can see in a display device like a monitor or goggles. You can go further and add more sophisticated functions to your FPV system like on Screen Displaying information and adding an OSD device.
Your eyes in the sky, when choosing your camera you should try to focus on certain characteristics like the image resolution, the ability for the camera to adjust to different light conditions and low latency. There is a lot of good options out there but the main kind of cameras used in FPV are the CCD or CMOS.
The image resolution is determined by the TVL (TV lines) measurement unit. The higher the TVL the better. The most common cameras used in FPV are 600TVL or 700TVL which provides a decent image quality but you can take it up a notch and use an 800TVL or even a 1200TVL which seems to work much better with HD monitors or goggles.
Video output. NTSC - PAL
Depending on which part of the world you are located you may have to chose what video output your device runs, however this is not an issue anymore because some FPV dedicated devices can switch between these two modes.
CCD (charge coupled device) and CMOS (complementary metal oxide semiconductor) image sensors are two different technologies for capturing images digitally. Each has unique strengths and weaknesses giving advantages in different applications. The cameras with CCD sensor is a bit more expensive than CMOS cameras but have better performance in scenarios with different light conditions due to it's advantage of processing the information and obtaining a digital signal.
Cameras like Gopro and Mobius use the CMOS sensor. You can use them for FPV but you will notice higher latency beside the slow response to light changes. We strongly recommend to use a dedicated FPV camera like the Eachine FPV Camera which includes the video transmitter, a current filter and it's a plug and play option.
VIDEO TRANSMITTER AND RECEIVER
These two elements are key to achieve a good quality and reliable video. We don't want to lose the video signal suddenly causing a crash or even worse to lose our beautifully built aircraft.
The most common frequencies used in FPV are.
- 900 Mhz
- 1.3 ghz
- 2.4 ghz
The lower the frequency, the better penetration ability. Also the lower the frequency the bigger the antenna that must be used. Before using an FPV device you should research about local Region or Country regulations that may apply.
The most popular frequency is 5.8 ghz because it is legal in most countries, cheaper, it uses a small antenna and it doesn't cause interference with the radio control system.
Some receivers have up to 32 channels so you have the option to select different channels when flying with others so your video signals are not conflicting causing interference.
These radios can be rated at 25mW, 250mW, 600mW and even 1000mW. The higher the power the longer the transmission range. We have tested these radios and for FPV racing purposes we find the 250mW radio has enough power to transmit decent video signal up to 1 Km with a clover leaf antenna in a space without obstacles like buildings or trees.
Types of antennas
For FPV purposes we will talk about the most commonly used antennas and their characteristics.
1. Linear polarized antenna: these are the "normal" antennas which usually come from stock with the radios. These antennas are linear polarized, which means that they radiate in only one aircraft, either vertically or horizontally.
2. Circular polarized antenna: Circular polarized antennas emit a signal similar to a doughnut when you look it in 3D diagrams, these are the most popular antennas due to their ability to maintain a consistent video signal regardless the position of the antenna. There are two kinds of circular polarized antennas, the Clover leaf antennas have 3 lobs and they are ideal for transmitters. Skew planar antennas have 4 leaves and they are ideal for receivers.
Which antenna should I use and why?
The main difference between these first two antennas is the way they signal is spread. Linear polarized antennas transmit waves in a single plane.