Hi,im waiting my argtek antenna and i ordered a 2.4ghz booster and a 5.8ghz booster to solve the problem. I will get a 16dbi antenna tu put on my argtek,better than the 7dbi. Here the links to do a similar setup :
5.8ghz booster
5.8Ghz FPV Transmitter RF Signal Amplifier amp For DJI RC Airplane...