title_body: Why is 5.8ghz used for FPV and 2.4ghz use for transmitters? Why do most VTXs use 5.8ghz and most transmitters use 2.4ghz?
upvoted_answer: As is discussed in this Oscar Liang article, FPV hardware exists for all different kinds of frequency bands, stretching from 900 MHz to 5.8 GHz, with 5.8 GHz being the most popular today. People in our hobby have tried nearly everything under the sun. :)
  
  Probably the most well-known tradeoff in RF is that between frequency and penetrating power. In general, higher frequency transmissions will not be able to travel as far and penetrate as many obstacles as lower frequencies.
  
  This would make it sound like lower frequencies would always be better, but this is not the case. Especially in the case of FPV video, available bandwidth and interference issues become more of a concern than pure range.
  
  With increased frequency comes higher bandwidth and reduced latency, which is to say that the 5.8 GHz band accessible to us can support more data throughput at a lower latency than the 2.4 GHz band. This is critical because video transmission requires several orders of magnitude more data to be sent than RC controls and telemetry do because it sends entire pictures instead of a few numbers per transmission.
  
  The Troubles With 2.4 GHz FPV Radios
  
  The need for more bandwidth in the 5.8 GHz range is further compounded by the fact that our analog FPV systems usually aren't frequency-hopping. In the old days of the RC hobby when airplanes were the only option, most RC transmitter/receiver systems had a fixed operating frequency. I have a couple of these transmitters, which actually have a slot where you need to insert a special crystal oscillator to select which frequency the transmitter uses!
  
  This became a problem once people started coming together to fly and the RC hobby became more widespread. All of a sudden, people would begin turning on their transmitters at the flying field and their transmitter would talk over other people's transmitters using the same frequency, blasting them out of the sky and interrupting the controls to their plane. (does this sound familiar? XD) This issue was worsened by the fact that the 2.4 GHz band we are allowed to use doesn't allow for very many non-overlapping channels and because the 2.4 GHz band is used by many other different kinds of devices and appliances which can also step on RC transmitters' signals. 
  
  The solution to this problem, which has been implemented in the vast majority of all 2.4 GHz RC systems, is to implement frequency-hopping. This feature allows the RC system to dynamically switch between frequencies on the fly as needed, without any input required from the pilot.
  
  These same issues caused by transmitters stomping on each others' signals are also a massive issue in the 5.8 GHz band, but to a far lesser extent due to the vast array of different non-overlapping channels available for use.
  
   (cit.)