So there is a theory where if a drone fly close to water surface (fly low close above water), the signal reflected by the surface and get weaker. So the lower you fly above water, the weaker the signal.

Also another theory is environment factors include density of the air which is affected by the ambient temperature and moisture. Hence the signals would be better at night, than during the day.

Is this 2 theories true?

How close are you talking?  As the VPS on the drone would stop it from getting below about 2 ft

DAFlys Posted at 3-19 00:24
How close are you talking?  As the VPS on the drone would stop it from getting below about 2 ft

Im not sure. Asking for a friend. Let say around 10 to 15 meter

umaruwa Posted at 3-19 00:44
Im not sure. Asking for a friend. Let say around 10 to 15 meter

I regularly fly over at 10 to 15 feet and have not noticed any signal drop off beyond what you expect with distance.

DAFlys Posted at 3-19 00:52
I regularly fly over at 10 to 15 feet and have not noticed any signal drop off beyond what you expect with distance.

Ya but in this case is flying low above water. So ive been told that the signal will reflect on the water and affect the drone radio signal strength. Not sure whether this is true or not

umaruwa Posted at 3-19 01:07
Ya but in this case is flying low above water. So ive been told that the signal will reflect on the water and affect the drone radio signal strength. Not sure whether this is true or not

Thats what Im saying,  I regularly fly over water at 10 to 15ft and have no noticeable drop off in signal.  

Hi, umaruwa. Thank you for reaching out. Please see the details below
1. It is not recommended to fly the aircraft close to the water (within 2 m from the surface). When flying above the water, the vision positioning function maybe not function well and only the GPS and barometer are used for positioning. The aircraft may even drop into the water. The main factors that affect the drones’ GPS signals are environmental barriers, signal interference, and GPS hardware malfunction. Multi-path effect: That is to say, a large area of the reflective board, a large area of water, etc. It will affect the RC signal by the surface and get weaker.
2. Yes, it will be affected by environmental factors including the density of the air. Electric ionization layer: You can't see it intuitively. But when the time and temperature and the weather, the density of the air is changing dynamically. Generally speaking, less affectable factors will be better than versa.

Hope this provides the information that you need. Thank you for your support.

DJI Gamora Posted at 3-19 03:59
Hi, umaruwa. Thank you for reaching out. Please see the details below
1. It is not recommended to fly the aircraft close to the water (within 2 m from the surface). When flying above the water, the vision positioning function maybe not function well and only the GPS and barometer are used for positioning. The aircraft may even drop into the water. The main factors that affect the drones’ GPS signals are environmental barriers, signal interference, and GPS hardware malfunction. Multi-path effect: That is to say, a large area of the reflective board, a large area of water, etc. It will affect the RC signal by the surface and get weaker.
2. Yes, it will be affected by environmental factors including the density of the air. Electric ionization layer: You can't see it intuitively. But when the time and temperature and the weather, the density of the air is changing dynamically. Generally speaking, less affectable factors will be better than versa.

Thank you very much for the explanation

umaruwa Posted at 3-19 20:38
Thank you very much for the explanation

You're most welcome, umaruwa. Should you need further assistance, please don't hesitate to reach us again here at DJI Forum. Have a good one!

Hello Every wireless communication are following the same Mathematical rules. Drone using 5,8 and 2,4 GHz band Fresnel obstruction may be limited as (In France don't know other countries) you must keep your drone with eyes contact. Which limit distance you are supposed to fly. Now as theory even with 30% first Fresnel zone obstruction signal should be sufficient. Then Transfert protocols may also allow Non line of Sight usage.
Concerning over water the main risk is also linked to obstacle detector which may have issue with water reflection and may not be able to evaluate correctly the distance to the water surface. To me this is a bigger problem than Signal transmission.
Have good day