Build: TX Common - Nixes/wifibroadcast GitHub Wiki

#Why are choices so limited? The video transmission side of the video system is the least flexible in terms of hardware. It must be a device with hardware h264 / mjpeg encoding, and it should be a device with a direct connection to a camera to reduce latency. This hardware must also be running linux (preferably something modern for better wifi device support). There are very few small board computers that fulfill all these needs, and even fewer that are affordable.

#Mainboard The mainboard choice mostly comes down to available space, if you want the smallest possible transmitter system then the raspberry pi zero 1.3 is the only choice. But if you can fit something bigger, then a raspberry pi 3 would be a better option, as it has greater potential for improvements to video quality and signal robustness.

#Wifi dongle The main decision to make here is the frequency you want to run at. Wifi supports a range of frequencies within the 2.4ghz and 5.8ghz spectrums. Choosing to use the 2.4ghz spectrum may result in issues when used alongside RC Transmitters that use the same frequency. In some cases it is possible to hack wifi dongles to work out of spec at slightly different frequencies such as 2.3ghz, but this has legal implications if you are not a licensed radio operator (who is?) and at that is not even legal with a license in some countries.

Thus in most cases, 5.8ghz is the only legally usable option. Unfortunately this leaves us with even fewer options for a wifi dongle, most wifi device manufactures prefer to use PCB antennas for dual band devices as they can better make antennas that function for both frequencies cheaper. This results in very few 5.8ghz capable dongles with a standard SMA connector.