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Mavic Radio Mods Primer

beanbubba

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Fellow enthusiasts,

I am coming up on a year as a mavic enthusiast. When I joined this forum, the veterans had been here since the product launched in October 2016 and it has been a fun and entertaining journey with all you fellow techno nerd/geeks (who are my favorite people in the world).

I have learned from the literally multiple thousands of posts here that the majority of us are career engineers or technologists in one discipline or another. In all my dealings with groups over my life, this is the smartest/cleverest concentration of folks I have ever worked with and it is truly a pleasure to interact and socialize with most of you.

My career technology has been with commercial Wi-Fi radio systems. After many many hours of observing and testing the mavic radio systems over the last year, I have concluded that the proprietary mavic radio systems are very closely related to the Wi-Fi radio chipsets and protocol behaviors. Subsequently, we are able to leverage hardware and techniques in the Wi-Fi world to the mavic radio systems to scratch the itch of those "mod" freaks in our group of enthusiasts.

I have a years worth of scattered posts in many threads that are very technical and not very useable for the typical drone pilot. So I decided to start a new thread here to compile and boil down the most usable bits of information related to mavic radio system mods for both the remote control (RC) and aircraft (AC).

I will have a few main sections to this thread. The first to be detailed now is what I am calling the "baseline" that covers the factory radio settings for the RC and AC. Once that is fully covered in detail, I will post the next section that enables the mavic radio "boost" mod and then compare it against the baseline. If we do not get the baseline details out of the way first, anything after that has no reference and IMHO is useless information. Then I have 4 different models of RF amplifiers to test on both the RC and AC and report the performance of each device. And along the way, I will test a handful of the most popular antennas and report their performance.

All of this will take some time, but I will try to add regular updates weekly until all of the variations have been tested and reported.

Regards,
@beanbubba

NOTE: I WILL EDIT THIS INITIAL POST WITH VIDEO UPDATES, CHECK BACK HERE FOR UPDATES OVER TIME.

:::

Mavic Radio System Observations 2.0
Birdside baseline.



Mavic Radio System Observations 2.1
Birdside+amplifier baseline.



Mavic Radio System Observations 3.0
Standalone amplifier baseline.



Mavic Radio System Observations 3.1
Continuous carrier amplifier baseline.



Mavic Radio System Observations 3.2
Aircraft and remote controller new baseline.


dronemods-2018-104.png

Antenna Coverage Visualization 1.0
This is a google earth video I did to help visualize different antenna types against the Grand Canyon as a backdrop. This was a simulation to help train laymen on antenna characteristics:

VIDEO: Antenna Coverage Visualization 1.0


Amplifier comparison results (for all DUT's) for both TX and RX across the entire receiver sensitivity range.

dronemods-2018-070.png

dronemods-2018-074.png


Mavic Radio System Observations 4.0
DJI Go4 Boost Mod

VIDEO: Mavic Radio Observations 4.0

video-stills-009.png


Mavic Radio System Observations 4.1
Boost vs Factory Amplifier Comparison

VIDEO: Mavic Radio Observations 4.1

dronemods-2018-112.png


Fresnel Zone Intro for Drone Pilots (pdf attached to this post):
 

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sonof40

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Subscribed. Thanks.
 

chazz

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Awesome! Keep em coming man. beanbubba productions has a nice ring to it ;)

I wonder if anyone ever tried using the unused ports?
 
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SkyNinja

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Sounds like a great project, I’ll definitely be following this thread.

If you’re interested I have a few MP Antenna systems that you can test, Just shoot me a PM
 
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mnoutdoors

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I would like to see what the signal does on the RC after say 30 minutes of on time does it start to reverse its transmit power or at some point does it disconnect?

Spectrum analyzer ordered :) 269.00, I want to test my antennas anyway, they work good for finding downed drones when fitted with real narrow antenna’s
 
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tanog

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Could you specify/proof of
RC's "R/T combo" and "RX only" port?
 

dsd317

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Very interested in this! Thank you for sharing your efforts in this area.
 

beanbubba

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Could you specify/proof of
RC's "R/T combo" and "RX only" port?
The only proof I have is personal experience. I have flown several miles out with both the bird RX antenna and remote RX antenna unplugged and disconnected from the radio boards
 

mnoutdoors

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BB, what dbi attenuator are you using? I have a 1-60 variable in 1dbi increments
 

tanog

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The only proof I have is personal experience. I have flown several miles out with both the bird RX antenna and remote RX antenna unplugged and disconnected from the radio boards
bird's one I s
The only proof I have is personal experience. I have flown several miles out with both the bird RX antenna and remote RX antenna unplugged and disconnected from the radio boards

Then, which one did u tested?
The only proof I have is personal experience. I have flown several miles out with both the bird RX antenna and remote RX antenna unplugged and disconnected from the radio boards
My test was LEFT printed on RC has combo port. RIGHT printed one was RX only.
yes this is 1T2R antenna scheme same as birds scheme.
Same port scheme as u tested?

Afraid about their Antenna-chain scheme dynamically at some situations...
 

beanbubba

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Short answer ,If true means 1 transmitting 2 receiving

Long answer, page 8


http://downloads.hindawi.com/journals/specialissues/145176.pdf
That is an excellent reference paper, thanks for sharing!

I can only guess what the mavic radios are doing, but if they are similar to Wi-Fi MIMO, having multiple RX inputs doesn't increase signal strength, but can increase overall data throughput. But if you are a distance flyer, MIMO wouldn't work very well except in close range where there are natural reflections.

But I promise you that the Mavic AC and RC have one TX/RX-combo port, and one RX-only port.
 

mnoutdoors

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I tried something today, I took my MP out a ways with my double amplified antenna both sides powered up as I would normally fly. Then I unplugged the power on one, the right side and waited nothing happen,video and rc 100% on Litchi repowered then I unplugged the left side power and the RC signal dropped to 75 then 45% plugged the power
Back in came back up 100% so is this meaning the left side is RC favored?
 
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