Video Systems: Cameras And Radio Gear
An FPV setup is defined by its video system. A camera is core to this setup, and there are various options to consider. Some enthusiasts even go so far as to use two cameras. The first one, of course, is FPV-specific, used for flying. The second is typically an HD camera that enables high-quality recording during flight. Those gorgeous vistas you see from quadcopters don't come from the same camera used to fly the multi-rotor, in other words.
There's always the option to use the recording camera as a flight camera with video-out cables, but quality and light management suffer compared to a purpose-built flight cam. Then again, if you don't need the ability to record your exploits, stick with a single camera. Your setup is going to depend largely on personal preference and available budget.
GoPro is the brand most enthusiasts favor for their recording cameras. The Hero3's high image quality, abundance of recording options, and compact form factor makes it ideal for multi-rotor applications. There are several alternatives, though. The action camera market is rapidly expanding, and similarly small recording devices aren't difficult to find.
One less-known solution comes from the Chinese brand Mobius. Its small, affordable action cameras offer respectable specs, though they're not quite up to par with GoPro’s high-end offerings. Still, lightweight and easy to mount, they’re not to be underestimated.
Compared to recording cameras, FPV “CCD” flight cameras deliver lower contrast, brighter images, and more dynamic response to rapid changes in light. In short, they're designed to help you see better, translating to confident piloting. As with so many of the components we're discussing, there are a great many options. Some are better suited to this specific hobby, but most can be made to work.
Manufacturer recommendations are perhaps your best starting point. Pay particular attention to the TV lines specification, which effectively means resolution. More lines give you higher quality, albeit at greater cost.
All FPV-based setups, by their very nature, consist of a camera and a transmitter on-board, and a receiver and display device on the ground. As with any other broadcast, video is transmitted using radio signals. To some extent, you get to choose the frequencies you use for transmission, and this is an absolutely vital decision because it impacts the hardware you buy, the range you can fly, and the objects your signal can penetrate.
Note that I mentioned frequencies, plural. Multi-rotors with FPV-based control schemes employ one frequency for the video and another for controlling inputs. You cannot use the same frequency for both due to interference.
Lower frequencies have much greater penetration through obstacles, and require less transmission power to travel the same distance. You'll find that those lower frequencies are reserved for the transmitter, since control range and penetration take priority over the video feed. Higher frequencies offer few advantages, other than smaller antennas, slightly sharper image transmission, and in some cases, bandwidth availability.
The frequencies most often used for FPV are 900 MHz, 1.2 GHz, 1.3 GHz, 2.4 GHz, and 5.8 GHz, with the latter two being most common. Others can be used as well, though the hardware is tricky to find.