Mavic2 Radio & Antenna Mods

[beanbubba]

I am going to continue more testing but I think I figured out the M2 radio basics. What was messing me up is that the Go4 app would constantly reset the radio mode to “auto”. Now I bring up the HD config page in the go4 app and hard set the band to 2.4-only and leave that screen up while I take off. Once in the air it will stay sticky to the setting (2.4 for my last tests). I did a few several mile tests with the bird side right antenna (black coax) disconnected from the main board; I had the RC left port disconnected and the right port going to a dragon 2.4 amp booster. NOTE: the M2 RC coax ports are REVERSED from the M1.

I will continue to report testing, but wanted to get this out so you can use your old M1 radio gear on your M2.

EDIT: it is not required to take off with the band setting page open for it to stick. But I did conclude that whenever you manually set the Go4 app HD config page to 2.4-only, there is a hard timer that starts and if you do not take off in X number of minutes, it will reset to "auto". This is what was tripping me up all week during testing. The bird is constantly dipping its toes in the other band checking for clean channels. If your gear is not setup to transmit 5 gHz signal it wreaks havoc on the radio system performance.

BTW - I have a batch of 5 gHz amps and antennas on order and will compile test results against 2.4 and then you can decide what's the best solution for you if building a new radio/antenna kit for your M2. And I have a set of dual band gear to compare as well. Concurrently I will be testing a few bird side radio amp options too. Probably will take me a month to complete properly.

 

[beanbubba]

I did some quick tests today and had the "dragon" 2.4 and 5 gHz amps and ran the same course with everything identical except for the amp itself. As expected the 5g underperformed against the 2.4g variant. I have noticed that the M2 bird side video transmit is not as effective or powerful as the M1. From all tests so far, the RC will never lose connectivity and the video stream will drop well in advance of an RC radio loss of transmission. This makes for a good argument for bird side amp's and I have that testing left on the to-do list. This is just one small test and we should not make final conclusions until all the results are in next month.

The main point of this early test is to put to bed the theory that 5g will out perform 2.4g like some very early phantom birds displayed. When all else is equal, 2.4g will out perform 5g in the neighborhood of 25% on the M2 for radio performance.

 

[SkyNinja]

I’m thinking about cracking open my Titan atlas and swapping the amps out for those duel band amps you posted earlier.

 

[beanbubba]

I’m thinking about cracking open my Titan atlas and swapping the amps out for those duel band amps you posted earlier.

You will need a lot more real estate with this unit:

 

[SkyNinja]

You will need a lot more real estate with this unit:

View attachment 47032

Nope not going to fit, guess I’ll just going to DIY it

 

[CyberNate]

EDIT: it is not required to take off with the band setting page open for it to stick. But I did conclude that whenever you manually set the Go4 app HD config page to 2.4-only, there is a hard timer that starts and if you do not take off in X number of minutes, it will reset to "auto". This is what was tripping me up all week during testing. The bird is constantly dipping its toes in the other band checking for clean channels. If your gear is not setup to transmit 5 gHz signal it wreaks havoc on the radio system performance.

BTW - I have a batch of 5 gHz amps and antennas on order and will compile test results against 2.4 and then you can decide what's the best solution for you if building a new radio/antenna kit for your M2. And I have a set of dual band gear to compare as well. Concurrently I will be testing a few bird side radio amp options too. Probably will take me a month to complete properly.

You can permanently force 2.4GHz by pairing the original DJI Goggles as the second Occusync device. This disables 5.8GHz band, even if you are not using goggles. I noticed this when I tried to use 5.8 and go app stated that I need to re-pair controller to enable 5.8. It wouldn't allow me to switch to dual or 5.8 mode.

 

[Elton Hammonds]

I am going to continue more testing but I think I figured out the M2 radio basics. What was messing me up is that the Go4 app would constantly reset the radio mode to “auto”. Now I bring up the HD config page in the go4 app and hard set the band to 2.4-only and leave that screen up while I take off. Once in the air it will stay sticky to the setting (2.4 for my last tests). I did a few several mile tests with the bird side right antenna (black coax) disconnected from the main board; I had the RC left port disconnected and the right port going to a dragon 2.4 amp booster. NOTE: the M2 RC coax ports are REVERSED from the M1.

I will continue to report testing, but wanted to get this out so you can use your old M1 radio gear on your M2.

#Ordered

With my Raptor XR antenna, these amps and my new Lenovo Tab 4, I'm hoping for improved comms that will lend itself to a much better quality video feed.

 

[beanbubba]

Can't wait to try this bad boy out! It's huge!!

Check out the receiver gain that is so sorely needed for the M2. I hope this tests out as advertised.

 

[beanbubba]

You can permanently force 2.4GHz by pairing the original DJI Goggles as the second Occusync device. This disables 5.8GHz band, even if you are not using goggles. I noticed this when I tried to use 5.8 and go app stated that I need to re-pair controller to enable 5.8. It wouldn't allow me to switch to dual or 5.8 mode.

What an odd anomaly, but thanks! I will try this weekend.

 

[beanbubba]

I completed a preliminary bench test in 2.4 gHz-only to compare the Sunhans SH-RC-5824G2W and Sunhans SH24Gi10W against the "Dragon" amp/booster. The Sunhans SH24Gi10W is a bad a** booster and the best I have ever seen in this class. It is pricey, but if you need power, this unit delivers.

NOTE: since the forum site software was updated a few weeks ago, I have received reports that attached files to a thread are not visible and report an error. Please let me know if you can see the 3 attached files in this post or not.

2.4 Test
Sunhans SH-RC-5824G2W
Measured peak output: 33 dBm / 2 Watts
https://www.amazon.com/gp/product/B073GS2QCQ/

2.4 Test
“Dragon” Amp
Measured peak output: 35 dBm / 3.2 Watts
https://www.amazon.com/dp/B01B94U438/

2.4 Test
Sunhans SH24Gi10W
Measured peak output: 40 dBm / 10 Watts
https://www.amazon.com/gp/product/B06X43QFH5/

 

[SkyNinja]

I completed a preliminary bench test in 2.4 gHz-only to compare the Sunhans SH-RC-5824G2W and Sunhans SH24Gi10W against the "Dragon" amp/booster. The Sunhans SH24Gi10W is a bad a** booster and the best I have ever seen in this class. It is pricey, but if you need power, this unit delivers.

NOTE: since the forum site software was updated a few weeks ago, I have received reports that attached files to a thread are not visible and report an error. Please let me know if you can see the 3 attached files in this post or not.

2.4 Test
Sunhans SH-RC-5824G2W
Measured peak output: 33 dBm / 2 Watts
https://www.amazon.com/gp/product/B073GS2QCQ/

2.4 Test
“Dragon” Amp
Measured peak output: 35 dBm / 3.2 Watts
https://www.amazon.com/dp/B01B94U438/

2.4 Test
Sunhans SH24Gi10W
Measured peak output: 40 dBm / 10 Watts
https://www.amazon.com/gp/product/B06X43QFH5/


View attachment 48289View attachment 48290View attachment 48291

How does the Sunhans SH- RC24G3W compared to Sunhans SH-RC-5824G2W?

 

[Drone_guy]

I can see the attachments.

 

[beanbubba]

I finished the combo battery controller + booster/amp mod and used the 2.4 "Dragon" amp.

 

[beanbubba]

After a few long range test flights, the M2 has the exact same antenna coverage difference depending on if you are coming or going. This mod on the left/port side front rotor arm antenna balances this out very nicely and verified in test flights today. Note that you can only secure 2 of the 3 screws when rotating the antenna 180 degrees. But it seems plenty sturdy and I am not worried at all.

 

[beanbubba]

Good and bad news from bird side amp testing today. When placing the amp inside the battery shell case, the amp is only one layer of plastic away from the ESC board and we all know about the near field interference at high motor loads. Well that was confirmed today and my dragon amp (even though wrapped in a home made foil jacket) would drop signal to the RC during full throttle aggressive flight. I swapped out the dragon amp for the sunhans model (and left the metal case intact) and it was able to survive the interference issues. Alternatively, you can place the unshielded amp outside the bird and away from the ESC board an inch or two and this also resolves the problem. The metal case that comes with the dragon amp is ridiculously heavy and not viable do to its massive weight. The sunhans performs nearly as well as the dragon and testing today was fantastic when paired with the RC side sunhans 40 dBm amp + panel antenna (and the flipped front left/port antenna on the AC). Just fabulous!! I will get around to documenting this and testing on the spectrum analyzer, but initial results are very promising.

 

[beanbubba]

I moved the radio coax cable to come thru the shell at the front of the aircraft and taped the U.FL antenna connector in place. It is so tiny and fragile, it would shake loose during flight. I removed the bottom of the battery case but left the end piece to anchor the battery controller firmly. I then removed all the battery components on the top and side shell and routed the balance cable thru the side hole where the release button used to be (this was all to save weight to offset the added metal case on the sunhans amp). I then taped the battery shell to the M2 frame and that concludes the mod.

When all was said and done, this mod change added 7 grams total weight.

 

[beanbubba]

Even though I have sworn off thunderpower batteries, these two 4500 LiHv's are the best performing batteries I have ever used before.

I did a long range test today, mostly to test the bird side radio booster. But at the same time got to test these batteries again. I was fighting 15mph winds during the flight and still reached 36000 feet and landed at 3.64 volts. That was with dual TP4500/LiHv's and NO factory battery.

Anyway, the point of the test flight was to measure the the radio performance of the combo bird side sunhans 3W amp paired with the RC sunhans 10W amp (and the flipped left antenna bird side). I was blown away and this is hands down the best performing mavic radio solution I have yet to witness.

See the attached pictures and note that the HD bars are pegged the entire flight (even over the power lines that lost signal last time).

PS - the Itelite 19 dBi panel antenna I referenced in prior posts did not perform well and I have put it in the junk pile of discarded drone parts. Not sure what its problem was, but it was not good at all. I went back to my company manufatured 14 dBi 30x30 degree beamwidth antenna and it is still the best money can buy for this application.

EDIT: this collection of radio parts performed so well that I don't have anything further to test looking for better performance. This is now my current reference design solution until something else new comes along in the future.

And again like the M1, dual amps at the RC is a waste of money. Cable a single amp to the RC right port and that's all thats needed.

 

[lolo780]

The 10w RC amp is like putting a train horn on your car. I love it!

Is there a way to figure out the optimal ratio of AC to RC power if you know the antenna gains on each side?

For example the 20w Sunhans is probably overkill if you have 2W of AC power?

 

[beanbubba]

Here is the bill of materials if anyone wants to DIY and make their own radio system kit like mine.
Good luck!

Remote Controller Radio Amplifier
https://www.amazon.com/gp/product/B06X43QFH5/

Aircraft Radio Amplifier
https://www.amazon.com/Sunhans-eSunRC-3000mW-Booster-compatible/dp/B07855N7DZ/

Remote Controller Coax Adapter
IPX IPEX U.FL UFL to RP-SMA Female with 1.13mm cable coax Z type FPV for DJI UAV | eBay

Aircraft Amplifier Coax Adapter
2-pack SMA Male to IPX U.FL Plug Connector Adapter | eBay

Aircraft Antenna Coax Adapter
1Pcs IPX / U.FL to RP-SMA Male Plug Pigtail Cable 1.37mm 20cm For PCI UE | eBay

Amp-to-Antenna Coax Cable
195 Series N-Male to N-Male Radio Pigtails

Amp-to-RC Coax Cable
http://www.l-com.com/coaxial-195-series-rp-sma-plug-to-n-male-radio-pigtails

Panel Antenna
https://www.amazon.com/HP-Outdoor-Antenna-ANT-2x2-2314-JW024A/dp/B01M8PVBXP/

Antenna Data Sheet
https://www.arubanetworks.com/assets/ds/DS_ANT-2x2-2314.pdf

 

[beanbubba]

The 10w RC amp is like putting a train horn on your car. I love it!

Is there a way to figure out the optimal ratio of AC to RC power if you know the antenna gains on each side?

For example the 20w Sunhans is probably overkill if you have 2W of AC power?

It is not a simple math equation. When using high gain directional antennas on one end of a point-to-point radio link, you can jack the signal and not worry about matching the other side (to a point). This typically only works in fixed radio/antenna positions, and when one or both of the radios is in motion/mobile, you absolutely need to match the radio capabilities on both sides of the link as close as possible.

But we are in strange territory here and fly our birds in perfectly straight lines and keep our remote antennas perfectly gazed on the air craft target. Therefore you can jack up the radio power and or antenna gain on both sides of the link as much as you can afford and you will still see benefit**.

**the bird side antenna needs to stay low gain omni - this is beyond the scope of this thread to explain.