The GHz soldering is behind hobby tools and skills.
The best results you can have is to get some 5.8GHz modules for $35
, and use them to make a system able to reach 15km or even more.
No joking, this is the electronics inside the system that holds current 18km record, for this class of gear.
But beware, the secret of this range are the antennas ! You will have a lot of "tinkering", in the real sense, to build the antennas able to give you such results.