I wouldn't recommend the usual Micro-Processors for long distances, even if they may work well.

TBS (Team-Black-Sheep ) has excellent bulletproof products with all the bugs worked-out,
and a ton of very useful features/options.
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this could help alot!

 

So somebody else claims to be doing it? Possibly they are. I never complained about design engineering ever being "hard" and so one sales weasel decided it must be easy. So that he could do it. And then he quoted it, and beat the competition quite well. And nobody could build it, which was OK because it did not work.
So the moral of the story is that not everything is simple, nor as simple as it looks.

 

Certainly it is very possible to transmit video 5KM Ham radio operators do it frequently. The equipment to do it is not terribly complicated. The big deal is IT IS MANDATORY TO HAVE A LICENSE TO TRANSMIT. The challenge of doing it in a drone will be weight, power consumption, and size.
Why didn't anybody offer help?? Because transmitting without a license is rather a big deal hen you are causing harmful interference to a lot of people.
The FCC and the FEDERAL MARSHALS have already busted some folks, and one company was fined quite a few thousands of dollars for doing just that.
And in this forum it is an official rule to not assist in doing anything illegal. They have other rules as well, but that is the one that stopped folks on this project.

 

Note where the specifications say
“* HAM license is required for operation on HAM channels, and HAM power levels! The VTx ships with only legal channels enabled, please consult the manual on unlocking procedure.”

In order to obtain a Ham license one has to demonstrate knowledge of applicable radio law as well as some technical knowledge. In other words,
Don’t do it.