Why signals become terrible after RTH initiation?

[fiberdude]

A seasoned MP pilot and owner of 2 MPs, I recently purchased a Phantom 4 Pro for comparison. To my great surprise, both P4P RC and HD signals are highly sensitive to RC antenna orientation (something unseen on MP remotes). Whats more, as soon as RTH is initiated with P4P completing a 180-degree turn, the downlink data connection is pretty much gone for the next 2-3 kilometres over the same trajectories it has just traveled at similar attitudes but with good signals. This happens over noisy residential areas as well as uninhabited bushes. I have attached a snapshot of Airdata.com notification page. HD frequency 5.8 GHz is used.

Can someone shed light on this MP-P4P divergence?

 

[Mark The Droner]

Looks like you're about three miles out? Would you say that's about the edge or your RC range?

You've got high wind warnings. Was that a cross wind? A cross wind will limit your range because it will force the antennas to be misaligned (not parallel) unless you think to tilt your controller.

Also, I am not sure why you dropped altitude so abruptly. If it was me, I'd stay high to regain signal, then drop.

 

[fiberdude]

At 6km (3.73 miles) heading out, the signals were still good (see the green entries from 5-5.9km). I could have gone further for another 1000m if I wanted to. I didn't plan to achieve my goal of 7km so fast.

The head wind (according UAV forecast) is only about 10km/hr at the altitude of 200m. At the 6km, I had 62% battery - plenty power, as its tailwind on the way back.

I dropped altitude due to two factors: 1) heading out, I only raised altitude to around 200m when it reached 4km. As I said, the drone followed the same trajectory in and out; 2) at high altitude, sometimes auto-landing could be triggered earlier than expected on RTH.