Following on from the 5.8Ghz log, I'm investigating some of the video transmitters used by drones.

MatekSys  VIDEO TRANSMITTER 5.8G VTX-HV W/ BFCMS CONTROL

• Input voltage: 7~27V(2~6S LiPo)
• 40 standard channels, A/B/E/F/R Band
• Output Power: 25, 200, 500mW switchable
• BEC Output: 5V/1A for Camera or FC

You can see details here http://www.mateksys.com/?portfolio=vtx-hv#tab-id-4

TBS UNIFY 5G8 PRO HV

RACEDAYQUADS MACH 2

These are all fairly low-cost (the VTX-HV is around £30), but they are not open-source, so I don't know the components used etc. But I'm sure we can have a look at them anyway! Even if they are not going to be used in the project!

POSSIBLE 5.8Ghz MODULES FOR USAGE IN PROJECT

Anyhow, just looking around, there are some 5.8Ghz TX modules that can be incorporated into our RF plugin for the robot station. We'll be making our own PCB with this and the 433Mhz module on it! We can't just use one of these video transmitters from drones! Because they are not open-source!

FX756T 5.8G 600mW 32CH 

So yes, a lot of the 5.8Ghz modules are lower power than this (600mW), so wouldn't be much good for our goal of 1km! This one seems promising!