Increasing the range of Mini with a 4 USD reflector

[new2mavic]

There was no wind this morning so it’s perfect for testing out the range of my Mini. The location is a suburban area so the level of interference should be quite low.

It was found that the antenna on the Mini is somewhat directional. The signal is significantly stronger when the tail of the craft is facing the remote controller.

Furthermore, the test was conducted over the sea so there should be relatively strong reflections off the sea surface. The direct signal and reflected signal will reinforce or cancel out each other depending the location of the craft. Such signal strength variation can be seen in the video. It is expected that the phenomenon will be less prominent over land as the reflection should be generally weaker.

The range is therefore not a single number but dependent of the criteria taken. If no interruption of signals ( uplink and downlink ) is permitted, the ranges are as follows :

Craft’s tail facing the RC : stock antenna : 1.8 km, reflector added : > 4 km ( I did not fly further out to reserve sufficient battery for the return trip )

Craft’s nose facing the RC : stock antenna : 1.6 km, reflector added : 2.5 km

Needless to say, I can’t be happier with this gadget

 

[lannes]

That looks like the threekings brand reflector ?

 

[new2mavic]

That looks like the threekings brand reflector ?

The brand is unimportant for Chinese products. The same item typically has a number of brands. Mine is branded "Sunny Life" . Despite the low price, the workmanship is quite good.

 

[EyesWideShut]

The range is therefore not a single number but dependent of the criteria taken. If no interruption of signals ( uplink and downlink ) is permitted, the ranges are as follows :

Craft’s tail facing the RC : stock antenna : 1.8 km, reflector added : > 4 km ( I did not fly further out to reserve sufficient battery for the return trip )

Craft’s nose facing the RC : stock antenna : 1.6 km, reflector added : 2.5 km

Needless to say, I can’t be happier with this gadget

@new2mavic - Thanks for the review. Good test.

I would like to see a test of passive range extenders where when the standard antenna signals break up and lost and the auto RTH is initiated, to allow the AC to come back a short distance where the signal is restored and then cancel RTH. During the pause slip on the reflectors and then continue the test to see the range difference under the actual same conditions. Would also like to see at the new loss of signal some yagi antennas put on and see if there's any further distance achieved.

 

[Capt KO]

I use the same reflector with a different name. Results very good. Not trying for additional range but just a good signal with less interference. ?

 

[jpit]

Not sure I understand. You say that the signal is stronger when the nose is pointed towards the remote control. Your stats don't confirm that.

 

[new2mavic]

Not sure I understand. You say that the signal is stronger when the nose is pointed towards the remote control. Your stats don't confirm that.

Thanks for the correction. I meant the signal is stronger when the tail of the drone is facing the remote control ......

 

[Deleted member 109934]

I'm surprised you only got 1800m with the stock antennas at height of 120m over water, I would expect way more, maybe ships below interrupted the test, I'm getting consistently 4km over the lake at 40-50m , with reflectors I battery is the limit I can hit 5000m but I'm scared to push for more. as my return battery level is 3-4%

 

[new2mavic]

I'm surprised you only got 1800m with the stock antennas at height of 120m over water, I would expect way more, maybe ships below interrupted the test, I'm getting consistently 4km over the lake at 40-50m , with reflectors I battery is the limit I can hit 5000m but I'm scared to push for more. as my return battery level is 3-4%

Actually I could go beyond 1800m if you watch the ( boring ) video. The signal came back after this first black-out point.

I believe black out occurred at that point because the signal reflected off the sea surface was out of phase with the direct signal so the two signals cancelled out each other. This point is dependent of the altitude of the craft, the lower the altitude, the further out this first black-out point is. As your altitude is a lot lower and lake water reflects less signal ( poorer conductivity ), you did not encounter such signal cancellation. I did not get that low because I want to avoid interference from the ships below as much as possible.

If there is any interference from the ships, only the control signal received by the craft would be affected. In the test it was always the video feed that got interrupted first so I don't believe the ships had any thing to do with it.

Here is some info on two-ray radio propagation model over ground ( or sea ) : Two-ray ground-reflection model - Wikipedia

 

[dweaver]

So question. I've only had my mini about a week now and have only flown out of site once at the park. I had the antanie point at he craft for the most part, and upright. At only 400 meters, it lost rc connection and the screen went black and white and froze. I did not have the height and speed reading out to me at the bottom and there was no audio. I panicked of course but luckily didn't do anything. And in a few seconds (seemed like hours) the screen came back up and I could see it was returning to home. Don't understand why it lost connection so close though, and wonder why I couldn't even see the height and speed. At least that would have given me some assurance. Is there a setting I have wrong?

 

[lannes]

So question. I've only had my mini about a week now and have only flown out of site once at the park. I had the antanie point at he craft for the most part, and upright. At only 400 meters, it lost rc connection and the screen went black and white and froze. I did not have the height and speed reading out to me at the bottom and there was no audio. I panicked of course but luckily didn't do anything. And in a few seconds (seemed like hours) the screen came back up and I could see it was returning to home. Don't understand why it lost connection so close though, and wonder why I couldn't even see the height and speed. At least that would have given me some assurance. Is there a setting I have wrong?

When you loose connection, you also could loose the telemetry data feed as well as the video feed.
Make sure you have the antenna's orientated correctly



Sometimes if you fly higher you have a stronger connection as you avoid interference from trees and other structures, that sit between the drone and remote controller

 

[dweaver]

Okay, thanks for the reply. I just wondered because it looked like on the video in this thread, that it kept reading altitude, speed and such after he lost connection.

 

[lannes]

Okay, thanks for the reply. I just wondered because it looked like on the video in this thread, that it kept reading altitude, speed and such after he lost connection.

You could try some cheap yagi antenna's to improve the range, you would need the 6 pole model for the FCC 5.8ghz frequency range that the MM remote controller uses in the US.

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