How do you stream video feed from a camera on a drone? I would think that at high altitudes Wi-Fi won't work.
So what would you usually do, and how?
It all depends on the video quality that you require. The short answer is to use a 3G or 4G transmitter, assuming that you are in an area with mobile coverage, to either a local device (Mobile phone) or a cloud based service.
Other options exist, including the use of XBee networks. XBee networks (depending on the series used and protocol, and whether you employ a regular or pro device) can offer ranges from a couple of dozen meters up to 16Kms or more (using a 900 MHz XBee Pro (in the US), or a 868 MHz XBee Pro (in the EU)). However, the data rate of an XBee will probably not be sufficient to carry video1.
However, Wi-Fi can be used for fairly large distances. The range of a Wi-Fi signal, can range from 300 to 2000 meters, depending on equipment and conditions. The range will varies due to a number of factors:
Don't forget that the quality of the stream will be less than if you were to record directly to an on-board storage (i.e. SD card).
The data rate is a non-starter. Xbee is designed for serial communications at a max of 230kbps. That's too slow for any kind of decent video
2.4 GHz Xbee products as well as 800 MHz products have data rates below 250kbps.
- 16 kbit/s – videophone quality (minimum necessary for a consumer-acceptable "talking head" picture using various video compression schemes).
Another thread, notes that the XBee's 250kps is half duplex, so that actual data rate is only ~125kbps. So, it would depend on the data rate of the camera that you wish to use.
Common solutions are from those who fly FPV (First Person View), they use simple analog cameras connected to 900 MHz, 2.4 GHz, and 5 GHz the lower the frequency generally the longer the transmission distance. With a 1 W 900 MHz transmitter with a cloverleaf antenna (a common antenna type), and a 18 dB gain patch antenna directed at your craft you can easily get 5+ miles line of site.
If your asking about large commercial UAV systems, e.g. the predator, they use satellites to transmit and receive telemetry and video.