I did notice this piece of equipment early in the video:
At first glance, it appears to be some form of active beam-steering antenna (closeup below)
If that is the case, is this active antenna handling the primary communication path, then relaying video and control link(s) to the handheld via low powered omni-directional radio (eg bluetooth, WiFi)? I could understand the 100mW power figure on airborne TX if there is such a high-gain ground unit as I’ve described.
Your suggesting some form of 2.4 ghz repeater of some sort with a high gain antenna.
It would certainly allow for a greater distance.
I will provide more information, videos and tests in the future.
This big antenna is a 5.8G video antenna brought by a friend, but it doesn’t work very well on that day.
This is why I didn’t provide videos in YouTube. I will join the video next time.
Oops, my apologies for jumping the gun on my theory.
Thank you for the clarification.
Nice endurance, You have courage to fly over sea ;O , I prefer hard land, in case something fails I can rescue something 
For public safety, I think flying over the sea is more responsible. If you lose your aircraft, you can buy it with money, but there are some things you can’t buy.
Ah, ok if you don’t have enought unpopulated field near, looks a good choice specially for your long travels, I avoid populated places too.
I live in one of the most densely populated places in the world. I can hardly find any space to fly 60 km. 
I hope I live in the desert, so I can fly everyday without worrying about safety.
I’d actually suggest shorter range tests with 30dB attenuators (or even more) on the antennas. It is quite hard to do real long range testing reliabily, much easier to test with an attenuator then extrapolate.
Once results are shown with an attenuator, then doing some real-world long distance tests are worthwhile as well, but they can be quite difficult to manage (getting line of sight, earth curvature etc)
Cheers, Tridge
My transmitter is 20db. According to the design, the sensitivity of my receiver is - 126dbm, and my attenuator is only 91db.
I’m also willing to test. It’s always difficult to find long range links for the legal frequencies in my country.
You can give me your address and I will send it to you by express. But you need to provide some test video pictures
Is this simply a pwm manual RC link (think Spektrum) or is it a serial telemetry datalink (think RFD900)?
This is a complete set of uplink downlink. It’s not a remote control + a telemetry.
The signal is transmitted 110 times per second and the received signal is 110 times. The transmitted signals contain control signals and app data, and the returned signals contain flight control data and other extended data. The receiver has SBUs serial port, PWM and USB. The transmitter has Bluetooth and USB interface to connect app.
There is a complementary relationship between antennas, rather than transmitting signals at the same time.
I live in a farm, first city at 30 km, I can give some tests if you need, looks interesting equipment for farming tasks. We need 5-10 km with safe connection, not at limit one.
