I don't know why Argtek choose that configuration, I think that the panels (like the ones in the stock configuration) are more directional than the omni antennas.
Also the 5ghz wave travels less than the 2.4ghz so I got the +14dBi directional for that reason.
Before the mod I was loosing video way before the RC signal, now with that configuration and only +6dBi at 2.4ghz I've tested very good video signal at 1200-1300mt.
this is my first test
Now I'm waiting for the delivery of a +20dBi omnidirectional antenna for the RC that maybe is also better than the panel, so I will let you know how it works.
Btw I'm not looking for greater distances, I'm ok with 1500mt, so I think that my final choice will be the one that gives more stability and ease of use.