As soon as you look deeper into FPV flying, you will quickly realize that not only are there many different brands of FPV equipment you can choose from, there is also a whole range of different FPV radio frequencies available.
Radio Frequencies for FPV
Usually people decide on what frequency they want to use before picking a FPV system equipment such as VTX and VRX. These are the common frequencies used in FPV equipment.
- 900 MHz
- 1.2 GHz
- 1.3 GHz
- 2.4 GHz
- 3.3 GHz
- 5.8 GHz
Differences in FPV Frequency
Generally, lower FPV frequency allows longer range and can penetrate obstacles better. Unfortunately, not all frequency bands are legal for hobbyists, and there are restrictions on how much power is allowed to use as well. This might be different in every country, so find out about your local regulations before getting into flying FPV. In this article, I will use the UK as an example.
In theory 900MHz should give you brilliant range and penetration. But it’s the least used frequency band for FPV due to the fact that the antenna is huge, and not many manufacturers make them currently.
This would have been the most obvious choice for FPV, but the UK government started using this frequency for mobile 3G networks in 2009, so it’s not legal to use for RC hobbyists.
This band provides great range and good penetration ability. However the antenna is huge, and you might also run into trouble pairing this next to your 2.4Ghz radio transmitter, as they sometimes interfere with each other. Low pass filters are often used to solve this problem.
But again it is illegal to use for FPV in the UK.
Similarly good range and penetration ability when compared to the 1.2GHz band. People in America use this frequency band for transmitting video/audio if they have a Amateur Television or ATV license from a ground based station. For the UK at the moment it is used for aerial work, so it’s illegal there.
You can get decent range out of this frequency band, and it has a very good range to power ratio. It was much more popular back in the days with 27MHz, 72MHz and 433MHz radios, because they wouldn’t interfere with each other. Less so now as we FPV hobbyists mostly use 2.4GHz for radio control.
The penetration ability is not as good as the previous frequency bands. Also given the fact that it is the most used band in many different devices and equipment, such as WiFi, Bluetooth, RC transmitters/receivers, and even Microwaves, you might run into some serious interference issues. So usually if you decide to go with this band for FPV, you need to choose a different frequency for your RC transmitter other than 2.4GHz.
3.3GHz is a relatively new frequency for FPV. It’s potentially a good alternative to 1.2GHz and 5.8Ghz, as it offers greater range than 5.8Ghz, yet the antennas are relatively smaller when compared to 1.2Ghz. It also doesn’t interfere with 2.4Ghz radio control links. However, 3.3GHz is illegal to use in many countries for FPV, so check before using it.
5.8 GHz is confidently the most popular frequency band among them all for FPV. The antennas can be made very compact because of the higher frequency. Equipment is also being made cheaper and cheaper due to the higher demand, as well as becoming smaller to follow the trend of smaller FPV models (even micro brushed quads). Finally it also doesn’t affect 2.4GHz radio control links, making it a great companion frequency.
It does have a decent range to power ratio, but because of the high frequency it has a very poor penetration property. Therefore flying is mostly restricted within the line of sight area and for short/medium range flying.
Legal FPV Frequency and Power Level In The UK
Not only are there certain frequencies that are illegal for FPV flying but there are also constraints on the video transmission power levels as well. For more detail check out this PDF.
So we know we can only use 2.4Ghz and 5.8Ghz frequency bands for FPV in the UK, we will have a look at these for their max legal transmission power level.
For 2.4Ghz, the max power is 100mW. For 5.8Ghz the max power allowed is 25mW. (information from here)
It’s worth knowing that even in 5.8Ghz, some channels could still be illegal. So make sure you know which ones are allowed in your country.
Conclusion – What Frequency Should We Use for FPV?
Flying FPV legally in the UK can be frustrating, most decent FPV equipment is basically illegal to run due to the transmission power restrictions. However if we are only talking about frequency, the most popular choice is using 2.4 GHz for Radio control and 5.8 GHz for FPV, for reasons of being legal and the cheapest options.
Some people have also suggested using 35MHz for radio control, which gives us excellent range and faultless results for control, as the 35MHz doesn’t affect the video signal at all. And use the 2.4GHz for FPV, which keeps us all legal and having good video quality. But 35MHz radio is extremely rare these days.
I have also seen people flying FPV using an illegal frequency and transmission power level A LOT without getting caught (such as 5.8Ghz 600mW). When you are flying in a remote site, I seriously doubt anyone would notice you are there using an illegal frequency band, unless you annoy someone by affecting or interfering in their activity. Of course, you should always follow the law, and don’t do anything unsafe or stupid.
There are also things to consider when choosing a frequency for your FPV system due to the fact that harmonic frequencies can cause interference. For example 2.4GHz might interfere with 5.8GHz. But from my experience it doesn’t seem to be too much of a problem for myself or other people I know, so I will save that for another article.
- Jan 2014 – article created
- May 2017 – article revised