This article describes in detail what specific FPV frequencies are suited for. My goal is to help you decide what frequency will work better for you. It can get very confusing starting out in FPV and hopefully this will clear any confusion. For the sake of convenience all frequencies will be compared using the same type of antenna and power output. Most video transmitters and receivers come stock with a 2dbi "Rubby Duck" antenna and we will go with a 500mw power output for this comparison. For more information, please visit www.fpvhq.com
Many people use 900mhz for FPV and are happy with the frequency. It can go the furthest distance using the same power output. This can be very helpful when your goal is distance. This frequency is also good at going through objects like trees and other obstructions but it has a couple of downsides that I would like to point out. Interference is a big problem with this band and this is because the airwaves are crowded with it. Verizon Wireless uses 900Mhz for some of their cell phones which can sometimes interfere. Antennas are also a problem. 900mhz has the largest antennas out of the all the frequencies we will talk about. The stock 2dbi antennas are not too large, but changing antenna type to gain range makes 900mhz a bad choice for portability. If your not worried about trying to increase range and are fine with occasional static then 900Mhz might be your choice. Take a look at the other options before you make your choice though
This is the next frequency above 900mhz. 1.2/1.3ghz will not go the same distance 900mhz can while using the same power but it brings some advantages that might make it a good choice for you. A big advantage is that is is less prone to interference than 900mhz is. This is because the airwaves are fairly clean from this band. Antennas will also be smaller which makes for better portability.
This is probably the most popular frequency. Many people use 2.4 and have great results! Interference is not a common issue with 2.4ghz which gives it an edge over 900mhz. Antennas are small which allows you to change antenna type and Dbi to gain range and not lose portability. The farthest FPV flight ever recorded was flown using 2.4ghz which shows how great this frequency is.
This is the cleanest frequency you could possibly use. This means you will not have to worry about interference. The downside to this frequency is distance. However it is a great frequency for park flyers who are not worried about distance. Out of all the frequencies, 5.8ghz has the smallest antennas which makes it very portable.