Remote signal strength when flying over water

[LeRoytheBoy]

Hi all,
I recently took my MA to Patong, Phuket, Thailand.
I did fly off shore to video and photo a Tall Ship that entered the area.
From the roof of my hotel, that happened to be across the road from the beach, I had clear vision of the beach and surrounding area's.

My question here is:- When flying over water, is there a stronger Remote to Drone signal strength, if you fly lower over the water.??????????

I recently watch a YouTube video about this subject that demonstrated remote car keys signal strength increase when placed near a container of water.

When I was flying out to the Tall Ship, I got out about 1.5 kilometers, and then started to get weak signal messages.
I would have been at a height of about 100 meters. Couldn't see the drone, but the remote would have had unobstructed signal to the drone.

I am wondering if I flew closer to the water, as stated in this video, whether the signal strength would have been stronger.?????????

 

[brett8883]

Hi all,
I recently took my MA to Patong, Phuket, Thailand.
I did fly off shore to video and photo a Tall Ship that entered the area.
From the roof of my hotel, that happened to be across the road from the beach, I had clear vision of the beach and surrounding area's.

My question here is:- When flying over water, is there a stronger Remote to Drone signal strength, if you fly lower over the water.??????????

I recently watch a YouTube video about this subject that demonstrated remote car keys signal strength increase when placed near a container of water.

When I was flying out to the Tall Ship, I got out about 1.5 kilometers, and then started to get weak signal messages.
I would have been at a height of about 100 meters. Couldn't see the drone, but the remote would have had unobstructed signal to the drone.

I am wondering if I flew closer to the water, as stated in this video, whether the signal strength would have been stronger.?????????

Unlikely. It’s almost always better to be higher for better signal strength.

 

[Dave Maine]

Extremely unlikely. The ocean is one gigantic ground plane from the perspective of rf signals.

 

[LeRoytheBoy]

If only I could find that YouTube video to demonstrate.
I searched for hours yesterday.
It was very comprehensive and explained in detail how water changed the signal length and distance of the wave lengths.
Oh well !!! I'll search again.
Thanks for your opinions.
LeRoy

 

[anotherlab]

If only I could find that YouTube video to demonstrate.
I searched for hours yesterday.
It was very comprehensive and explained in detail how water changed the signal length and distance of the wave lengths.
Oh well !!! I'll search again.
Thanks for your opinions.
LeRoy

Sorry, but no (for a couple of reasons).

With the drone's 2.4 Ghz and 5.8 Ghz radio frequencies, water acts like a dampener. I have no idea what YT video you saw, but if you want actual scientific proof, this study is pretty clear on the issue.

Even if what you saw was actually true, changing "the signal length and distance of the wave lengths" would mean that the radios would no longer see the signals because you have effectively changed the channel.

Also, radio waves go in straight lines. They wouldn't go in the water, gain strength, change vector to come back out of the water.

On the other hand, flying close to the water runs the risk of the drone going into the water or (I know this is remote) smacking into the side of a ship.

 

[WithTheBirds]

Sorry, but no (for a couple of reasons).

With the drone's 2.4 Ghz and 5.8 Ghz radio frequencies, water acts like a dampener. I have no idea what YT video you saw, but if you want actual scientific proof, this study is pretty clear on the issue.

Even if what you saw was actually true, changing "the signal length and distance of the wave lengths" would mean that the radios would no longer see the signals because you have effectively changed the channel.

Also, radio waves go in straight lines. They wouldn't go in the water, gain strength, change vector to come back out of the water.

On the other hand, flying close to the water runs the risk of the drone going into the water or (I know this is remote) smacking into the side of a ship.

View attachment 87604

The first thing that came to mind for me from the description was multipath propagation (reflections from the water surface). It is well understood that 2.4 and 5.8ghz links can show performance changes over tidal water bodies. Path length distances can and do lead to destructive cancellation at the receiver end. One obvious potential enhancement to signal performance may be increased SNR at the drone end, unlikely to be a lot of RF sources below the drone.

I’m unsure how your linked study might assist here where the drone remains above the water surface?

 

[Keule]

If only I could find that YouTube video to demonstrate.
I searched for hours yesterday.
It was very comprehensive and explained in detail how water changed the signal length and distance of the wave lengths.
Oh well !!! I'll search again.
Thanks for your opinions.
LeRoy

In a perfect/unobstructed environment, radio waves will travel in a relatively straight line from the RC to the AC (and back).
But if there are reflective surfaces that interact with a stray transmitted wave, such as bodies of water, the radio waves deflecting off the water may arrive either out-of-phase or in-phase with the signals that travel directly to the receiver.
Taking the Frensel Zone into account means, then lower you fly an AC above a water surface, then more likely the signal reception is weakened.

 

[anotherlab]

The first thing that came to mind for me from the description was multipath propagation (reflections from the water surface). It is well understood that 2.4 and 5.8ghz links can show performance changes over tidal water bodies. Path length distances can and do lead to destructive cancellation at the receiver end. One obvious potential enhancement to signal performance may be increased SNR at the drone end, unlikely to be a lot of RF sources below the drone.

I’m unsure how your linked study might assist here where the drone remains above the water surface?

It was to illustrate that a large body of water would not increase the range of the signa, the point made by the OPl. I did make the point that it didn't matter because the drone was above the water.