OK ... you have to look at what is being transmitted.
The 5.8 is telling the aircraft its flight ... left, right, rotate, fwd, back .... its better to have this omni-directional so you have control whichever way you are facing. If control goes down - smart RTH kicks in and aircraft comes home. The data transfer on the 5.8 is a lot less than the 2.4, but you want control to be more generalized.
The 2.4 is not only video, but telemetry as well. It is also a full two-way communication and needs best connection - so its directional to have major rf in direct line of the two units. If you lose connection of the 2.4 - its not a death deal.
The questionable part is the real fact about the two 2.4 panels ... are they as per other 2.4ghz radios - diversification ? Or actually doing slightly differelnt jobs. People will say they have only modified one and have good range - but that is not conclusive evidence .... and to be honest DJI is not forthcoming about technical details.
You can make the 5.8 more directional by fitting the parabolic reflector .... basically it reflects backward rf forwards to add to rf going forward. The curve is designed to provide correct reflective angle ....
The Argtek system keeps a similar setup of plates and centre stick antenna. But all external and larger.
DBS as others show here has decided to directionalise all ....
The choice of which you use - I think depends on what you want to do. I chose the Argtek, because I do not want great range, I want reliable consistent range of up to 1000m. At present I get about 700m but with variable video results.
Nigel
