Please help me understand...

[Asxetos]

Hi guys, i am a drone newbie and some help to understand things would be appreciated.

I bought a used P3A in good condition (second revision with the newer motors, brand new battery and brand new GL300C remote).
I have NOT flown it yet, i wanted to clear things first so i started reading this forum. A lot. Sadly i don’t think i found clear answers.


What is not clear to me are the reasons - benefits i would have if i stayed on version 1.7.6 for the AC, and 1.5.8 for the RC that i read so much about in this forum, and which android app version should be used with them.
On the other hand, what will be lost or gained if i upgraded everything to the latest version.


My situation is:

I am on version 1.7.6 on the AC, and version 1.5.8 on the RC with no "+" signs.

Using app version 2.4.2 i read that should be used, most things seem to be ok except in the "about" dialog, where i get N/A firmware versions for both the AC and the RC.
Checking with the graduation cap shows firmware version "null" for the remote, and will give no options to download-upgrade.

Using a higher app version (i tried 2.9.1, 3.1.5, and the latest 3.1.43) i get the correct AC and RC firmware versions in the "about" dialog with no "+" signs but then other things are dodgy, like weird or incomplete battery info, nagging to upgrade, etc.

Considering the above, i am hesitant to take the bird out for a real flight before some info clears.


Please clarify the version confusion for me...
Thanks.

 

[Fly Dawg]

I bought a used P3A in good condition (second revision with the newer motors, brand new battery and brand new GL300C remote).

From my own perspective, the app versions on Android do not make that much difference. As of today, I am using Android 7 with the latest GO and Litchi apps. FW is 1.08.8 and RC 1.6. I have been flying my P3A perfectly well with this same firmware, going on 3 years now and have never updated since. As far as Android goes, it is more the device itself that can become an issue. Whichever device you plan to use, make sure you have at least 2M of RAM, more is better but 2M at a minimum. You will get choppy and laggy video feed if you go lower than that.

 

[Asxetos]

From my own perspective, the app versions on Android do not make that much difference. As of today, I am using Android 7 with the latest GO and Litchi apps. FW is 1.08.8 and RC 1.6. I have been flying my P3A perfectly well with this same firmware, going on 3 years now and have never updated since. As far as Android goes, it is more the device itself that can become an issue. Whichever device you plan to use, make sure you have at least 2M of RAM, more is better but 2M at a minimum. You will get choppy and laggy video feed if you go lower than that.

Thanks, good to know.

Any definite info on power and range drop if you update on later firmwares?

 

[quaddamage]

We now have tools which allow us to compare power settings between firmwares, but no one did the comparison yet, AFAIK.

They definitely do change across firmwares.
And across versions of RC and OFDM module.

 

[3rdof5]

You say you bought a "new" battery. Is it possible that the dodgy battery info in the app is due to the battery might have too high of FW on its own out of the box?

 

[Asxetos]

You say you bought a "new" battery. Is it possible that the dodgy battery info in the app is due to the battery might have too high of FW on its own out of the box?

Just for the record, i bought a used AC that came with a brand new battery and new remote.
The battery's firmware is consistent with the drone's firmware. I updated on 1.7.6 and it reported a success.

I am just wondering if i should update any further, and which app version is best to use...

Thanks.

 

[quaddamage]

Ha, I got the lightbridge script running.

Here's a comparison of attenuations set in various firmwares. Note that this is OFDM board (air side) only! The GL300 has its own values.

- values represent attenuations of the RF signal at OUTPUT of transceiver in OFDM
- values are in decibels (I scaled some values according to description, hopefully correctly)
- there are different values for different boards - here boards are named ad4, ad5, ar6, ar7, ad2
- ad* boards are those with Analog Devices transceiver, ar* are with Artosyn transceiver
- the RF signal after transciever goes to RF amplifier, so differences between boards are due to different transciever and different amps used
- I can see that the attenuation values for "ar7" are ridiculously high.. I don't know what's up with that. This is what I received from the firmwares.

EDIT: I did some investigating on the ridiculously large values, and asked others about it. Turns out the table is correct - DJI made a mistake and reduced the range of board AR7 to circa 100 meters. These values were probably ment to be for AD2 board (for AD? boards, values need to be divided by 4 to get decibels, so that would make sense).
(ignore the above, the script had an error - reported it, so should be fixed soon)

EDIT2: Image updated.

EDIT3: I still have error somewhere in my sheet. Will provide updated table when I have time to figure it out.

 

[Asxetos]

Ha, I got the lightbridge script running.

Here's a comparison of attenuations set in various firmwares. Note that this is OFDM board (air side) only! The GL300 has its own values.

Wow,
This is the first and the most helpfull piece of information i've seen in all my searches for the subject. Proof that beyond 1.7.6 the range is significantly reduced when in CE.
10 decibels (and 35 for ar7) is A LOT of power loss.

On the contrary, when in FCC, in higher firmwares the power of ar7 and ad2 boards is increased. Only ad2 is down by a margin.

Thanks Quaddamage.

 

[quaddamage]

This is eye opener for me as well. I'm checking the data over and over, even peeked at assembly - but everything looks correct.

In at least 3 versions (maybe more - we don't have values from before FW V01.05) Dji didn't even differentiate the power between FCC and CE modes (remember the data is for AIR side only).

EDIT: There was an error - some values for ar7 and ad2 were switched. Updated the table in original post.

 

[Kirby Johnson]

Fly Dawg is (as usual) pretty spot on. I have a 3 Adv and fly it regularly, but not all day or anything.

I have had it for Y E A R S with no incidents , knock on wood, and these are the versions which I use:

Phantom 3 Advanced Software

DJI Go 2.8.1
Aircraft 1.9.60
Remote C 1.6.0
Flight Controller sn 03Z0243119

Your Mileage may vary. BTW with the version of Go I am using, I had to root my Android phone and hack the hosts file to disable the forced update. I suspect an earlier version would not require this.

My rule of thumb is never let anybody or anything update anything I own without my express approval. I let my guard down with DJI and then had to do a tiny bit of hacking because of it.