In this article we provide advice on how to choose hardware for an FPV setup, some useful tips about flying FPV and explain both basic, and advanced configurations of FPV systems.

Setting up an FPV system for the 1st time can be a little complicated, but due to the popularity of FPV, solutions are starting to become more user friendly. This guide has been written with the aim of providing the information you need to set up your first FPV quad, and to allow you to start flying FPV by covering the following topics:

• What is FPV
• Benefits of FPV
• How Does FPV work
• FPV Camera
• Video Transmitter / Receiver
• FPV Antenna
• FPV Goggles / Monitor
• Fresnel Zone
• Diversity
• OSD
• Voltage Regulator
• Power Filter
• Latency
• FPV Tips and FAQ
• Laws

What is FPV Flying?

FPV stands for First Person View. In FPV flying, a camera is used to stream real-time video from onboard the quadcopter (Drone) to the pilot on the ground. This allows the operator to see as if they were in the ‘cockpit’ of the craft. Because you are (hopefully) in control of your craft, rather than just having a bird’s eye view, an FPV system makes you the bird!

Other than FPV, we also have LOS. It stands for Line Of Sight and is the traditional method of looking at your craft while flying before we start putting cameras on our drones.

Traditionally a pilot controls an RC aircraft by looking at it line of sight (LOS). But in FPV the pilot sees what the drone is seeing, which is why it’s sometimes called video piloting.

Flying FPV can feel like playing a video game, but if you crash in the game, your PlayStation isn’t going to hit your lounge wall at 90MPH! Believe me, replacing a top tier FPV quadcopter can be just as expensive as a new PS4! The level of focus required while flying FPV is intense, and the speed and maneuverability of a mini quad make it a truly sensational experience every time you fly – regardless of how many props you might break :) It is solely due to advances in FPV technology that has made drone racing (mini quad FPV) a possibility in recent years.

Benefits of FPV

In addition to the excitement and addictiveness of flying FPV, there are many practical advantages too. Having an on-board view from your quad eliminates many of the problems faced when flying LOS, i.e. losing sight of the quad by flying into the sun or behind an obstacle, learning to fly ‘nose in’ (left and right are reversed when flying towards yourself) and misjudging the direction your quad is facing. FPV makes control over the quad much more precise, this really helps to take further advantage of the space you are flying in.

FPV is allowing pilots to fly further, higher and more aggressively than ever and it is a much more interactive way to experience the environment making the experience far more engaging for the pilot.

To summarize, FPV delivers:

• More agile flying
• More precise control
• Further and higher flight capabilities
• More fun!

How Does FPV System Work

FPV systems are actually quite simple, but there are a lot of products with different spec and features which can cause some confusion. However every FPV system uses the same core components:

• FPV Camera
• Video Transmitter (VTX)
• Video Receiver (VRX)
• FPV Goggles or Monitor
• Antennas

The camera is mounted on the front of a quadcopter, real time footage is then sent from a video transmitter, to a video receiver on the ground. And finally the video is displayed either on a monitor or a pair of FPV Goggles.

A more sophisticated setup may include telemetry, OSD (on screen display), DVR (digital video recorder) and other gear. Here we will go into more detail about each component within an FPV system.

FPV Camera

Originally FPV cameras were re-purposed security cameras, which were generally small, lightweight, and easily fitted to compact unmanned aircraft. Most FPV cameras these days are specifically designed for extremely low latency, while providing the best possible dynamic range for the rapid changes in lighting conditions that come with flying FPV. Due to this focus of low latency, FPV cameras are usually analog and not capable of capturing the digital HD footage that you see on Youtube, this comes from an additional Go-Pro or similar ‘action camera’ mounted on the quad.

When choosing any camera, the first thing we tend to look at ixs the resolution, but with FPV there are other important factors to consider too, such as latency and wide dynamic range.

Video Transmitter and Receiver

The video transmission system (including VTX – transmitter, VRX – receiver and antennas) determines the reliability and range of your video link.

Read about the basics of video transmitter for quadcopters in this post.

Here are some important concepts that will help you understand FPV frequency better:

• What frequency is used for FPV – this post explains the advantages of different frequencies, and why 5.8Ghz is the most common for mini quad
• Channels in 5.8Ghz frequency band – each frequency has a number of channels, which pilots can choose so they do not interfere when flying in groups
• It’s possible to allow more people to fly together by managing video frequency properly, such as utilizing more frequency bands and adding more frequency separation

Not all VTX and VRX operate on compatible channels, so make sure your VRX supports the channels your VTX uses. it could be brand dependent. Make sure your VRX supports the channels on your VTX.

Antenna for VTX and VRX

Learn about FPV antenna basics and how to choose the best FPV antenna in this tutorial. In this guide we cover:

• The Pro’s and Con’s of Linear and circular polarized antennas
• The differences between Omni-directional and directional antennas
• Different types of FPV antenna
• Antenna Connector types

VTX and VRX are often supplied with linear polarized antennas, they are more simple, cheaper to make and generally more durable, however they are not the best choice for multirotors and can be easily affected by interference. We recommend using circular polarized antennas for your FPV system to optimize performance.

Directional antennas with high gain allow longer range at the expense of a narrower angle of reception. A directional must face towards the multicopter to get the best signal. The performance of directional antenna quickly decreases when the craft moves out of this narrow angle. For more information, here is an article on how antenna gain affects range in FPV.

FPV Goggles / Monitors

FPV goggles are generally more expensive than a monitor, but goggles provide a more immersive flying experience.

There are some advantages to flying FPV with a monitor apart from cost, like allowing the pilot to easily switch between LOS and FPV. A monitor also makes it more convenient for those who wear glasses, though some manufacturers of goggles now offer a range of different lenses, even catering for prescriptions.

The experience of flying with a pair of FPV goggles is hard to beat, on top of the immersion, the image is clearer, the view is not so affected by sun light and they are also more compact for easy transportation.

The choice relies on personal preference, some people enjoy the immersive flying experience with FPV goggles, others feel uncomfortable wearing them. Some people even suffer from headaches while wearing FPV goggles. Also eye conditions could affect your usage of goggles. If you are interested in goggles, it’s best to borrow a pair from a friend, and try them out before making a decision.

FPV Monitor – What to Consider

If you decide on a monitor, there are a few things that you should look at:

• Correct video Input: make sure the monitor supports an AV input that is compatible with your video receiver
• Input Voltage: make sure the monitor can be powered by 2S or 3S LiPo, or another suitable power source of your choice
• Features: some monitors come with a built-in VRX or even a DVR, while not strictly necessary these can be nice features to have
• Size: In my opinion, the minimum screen size for an FPV monitor is 7 inch, any smaller and it becomes difficult to see clearly
• Brightness and Backlight: it’s important to be able to adjust the brightness of a monitor, and one with a backlight will serve you better. Flying in sunny conditions can wash out the colour and make it difficult to see the screen, even if you use a sun shield
• Blue Screen: When receiving a weak/no video signal, some monitors revert to a blue screen (or black). This is unsuitable for FPV, because when you’re on the edge of losing signal the picture will simply go blank, your quad will usually be far away at this point and invariably heading for the nearest puddle too! A screen that shows static when there is no signal is ideal, you might still recognize a vague image, allowing you to return to an area with better reception and avoid the dangerous zone. Another possibility is to add a DVR to “fix” the blue screen issue

Fresnel Zone

To ensure you have the best possible signal your VTX antenna should be in the line of sight of the VRX antenna at all times.

When you fly behind a tree, or a hill, your signal will weaken or even drop completely as you are outside of the Fresnel Zone. When this happens you might have video breakup or static on the screen. The problem becomes more pronounced with higher transmission frequencies. That’s why your 2.4GHz radio signal normally has longer range than your 5.8GHz video feed.

Remember that since most mini quad frames are made of carbon fibre, it’s important your antennas avoid having the signal blocked by the frame or other electronic components such as your HD camera.

Antenna Diversity & Receiver Diversity

A diversity system allows multiple antennas to be used at the same time, but be aware of the difference between “antenna diversity” and “receiver diversity”.

“Antenna diversity” only uses a single receiver so the 2 antennas aid one another with signal reception. “Receiver diversity” is a better system as it has 2 (or more) separate receivers, each is equipped with an antenna and it will always switch to the receiver with the strongest signal.

Using diversity allows pilots to combine “omni-directional antennas” with “directional antennas” to get the best of both worlds.

OSD – On Screen Display

An OSD is used to overlay real-time flight information about your multicopter into your live FPV feed. This is totally optional, but having flight data like battery voltage, GPS information, speed, altitude etc. can be extremely useful.

I personally use OSD on all my quadcopters whenever possible, mainly to report the battery voltage level, so I can land without over-discharging my LiPo.

Here is the OSD guide for beginners.

Input Voltage and Voltage Regulators

You need to make sure your FPV equipment is powered by the appropriate voltage. Many FPV equipment is rated for an input voltage of 12V, though a wider range of supported voltages are becoming more common these days.

For example if your equipment is rated for 12V, and you are running 3S LiPo, you could power it directly from your battery. However if you are using 4S LiPo or higher for your quad, you can power your FPV gear with a separate 3S LiPo though it’s not ideal due to the extra weight. Alternatively you can use something called ‘Voltage Regulator’, to step down the battery voltage in the case of 4S, it can convert 16.8V to 12V.

Power Filter (LC Filter and Capacitor)

Motors generate a lot of noise in your power system. If you are powering your FPV gear (e.g. VTX and camera) with the same battery as the one powering your motors, the noise could get into your video, which results in jumping white lines across the screen. This is especially noticeable with sudden changes in throttle.

An “LC filter” (a.k.a. “power filter”) is used to reduce noise or interference in the power to your FPV system. They can be bought ready made, or you can DIY your own power filter. Sometimes simply adding low ESR capacitors could also help clean up the noise.

Delay, Latency, Lag

“Delay”, “latency” and “lag” are all terms used to describe the amount of time it takes from your FPV camera capturing an image, to that image being displayed on your screen. The faster you fly the bigger impact latency has.

Each component in an FPV system can contribute certain amount of latency. See these articles for more information:

• FPV Camera latency
• VTX/VRX latency

FPV Tips and FAQ

Video Switcher

If you are running multiple cameras on your quadcopter, like an FPV camera and a GoPro, you might consider using a video switcher, so you can switch between these feeds on your FPV goggles or monitor by using a switch on your radio transmitter.

This is useful for those who are flying with their FPV camera, but also want to occasionally check what you are filming in the HD camera.

Video frequency conversion

Some FPV goggles have a built-in VRX that only supports 5.8GHz, if you want to run 1.3GHz or 2.4GHz, you could make a “repeater” that receives the lower frequency signal and then re-transmits a low power 5.8Ghz signal to the VRX in your goggles.

Can I use my iPad, smart phone or tablets for FPV?

You certainly can! You can either send your live video via wifi, or use an analogue to digital video converter to display the footage on your mobile device.

However this is not recommended, because the delay in the video stream will be so bad it could crash your drone.

Where to put my FPV components on the model?

Generally speaking, place your VTX antenna as far away from your GPS and radio receiver antenna as possible. You should also try to keep the wires for the FPV system away from motor/ESC wires, this help prevent unwanted interference.

What is “Jello” I hear about all the time?

“Jello” is a video effect where vibration from your motors and propellers are passed to the camera.

You might not observe jello through the FPV camera, but later find out the amount of vibration that has been captured in your HD footage is unbearable. This could be due to the different camera sensors and how their shutter works. Generally speaking CMOS is more vulnerable to vibrations and more prone to jello than CCD sensors.

What to do with FPV camera audio?

Some people actually prefer flying FPV with audio and feel that it gives a greater sense of being on-board, even though all you can hear is the sound of the motors and rushing air. If you don’t want to use audio, just ignore it or even cut the wire off and save a gram of weight.

How do you learn to fly FPV?

I often get asked “what the best way is to learn to fly FPV?”. Some might assume they have to become really good at flying LOS (line of sight), before they try FPV, but this isn’t necessarily the case. Remember that your FPV system can fail, so having some skill at LOS flying will help you get your craft back in control in an emergency.

LOS and FPV are two very different ways of flying. It is best to master basic controls flying LOS, and once you start to feel comfortable with how to move the quad around, you can move on to FPV.

Most pilots fly the ‘maiden’ (1st flight) of a new quad in LOS, before putting on their goggles, it is easier to see if any drift needs trimming out and helps to give an idea of how it responds to the stick inputs. 

FPV simulators can really help beginners pick up the basic skills quickly, they can dramatically reduce the cost of broken parts due to trying tricks that are beyond your capability and other silly errors. Here are a list of RC Multicopter simulators.

Laws Governing use of FPV Frequencies

Countries have different laws in place, restricting the amount of power a transmitter can produce and on which frequencies. Please check your local restrictions, and fly safely and lawfully. Here is a discussion about legally flying around the world.

That’s all

Hopefully this article has helped your understanding of the basics of an FPV system and provide some useful tips for flying FPV. Do your research, ask questions and make sure you understand what it is that you are buying.

source:https://oscarliang.com/fpv-guide/