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Total video loss or unit went into failsafe
595 13 2-9 06:42
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geoffgalgoyahoo.com
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I have complete DJI FPV set-up including controller, goggles, and air unit all updated with the latest firmware. I had an Iflight 5 inch drone using T-motor F7 stack, T-motor Hom 1750 kv motors, a capacitor on battery pads and using no third party receivers running on a 6s battery with 2 battery straps securing battery. I had over 20 successul test flights which included range testing with no issues. Today, I was cliff diving over the ocean 2 minutes into my flight while doing a power loop over the cliff and I had complete video loss or possibly the air unit went into failsafe with no warning signs like pixelations whatsoever. Unfortunately, I loss the quad and fell into the ocean. Extreme 128 megabyte micro SD card only in air unit and no SD card in my DJI FPV goggles. The quad was no more than 200 yards away when I loss total video signal and total loss of stick control on my tx I went immediately to acro mode to self-level when this occured with no success. No other analog pilots plugged in. Just my analog pilot friend and I were there at that location that day. We were spotting each other taking turns flying solo. We were never plugged in at the same during my uneventful flight. Has there been any other DJI FPV pilots experiencing this issue? Hopefully a DJI FPV series moderator can chime in. Thanks.
2-9 06:42
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mc54
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Flight distance : 1030 ft

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I had this happen 3 times before I stopped recording on the air unit.  It hasn't happened since.
And yes, I was using a Sandisk Extreme SD card.  I suspect it is more prone to happen on with a SD card that is getting full or wasn't formatted in the air unit.

Now I stick to recording just on the goggles, no problem.  I'd love.to continue recording on the air unit, but I'd want to be sure the issue was acknowledged by DJI and addressed in a firmware update first.



2-10 05:40
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GeoffGFPV
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mc54 Posted at 2-10 05:40
I had this happen 3 times before I stopped recording on the air unit.  It hasn't happened since.
And yes, I was using a Sandisk Extreme SD card.  I suspect it is more prone to happen on with a SD card that is getting full or wasn't formatted in the air unit.

I hope that DJI gets the attention of this issue and fix this problem as soon as possible. I saw other forum members having similar problems with freeze frame and total loss of video signal. For the time being, I will definitely not have a micro SD card in my other air unit and only in my DJI FPV goggles. I am glad I went to this forum and find helpful members like you. Thanks for you help. Much appreciated.
2-10 07:17
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schl0r
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United Kingdom
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I have had this too last weekend. Running the Infinity 30 Stack F4 and DJI FPV kit on the latest firmware. Video just froze mid flight, not even 100m away from me. I didnt know what happened at first but was able to reproduce this 3 more times whenever I did flips and I remembered being in the middle of a flip when it happened first time too. I was assuming voltage spikes etc - but I was not able to reproduce with 100% throttle punch outs.
My understanding was that the issue with the SD card writing causing crashes was solved with a previous fw upgrade though? And how likely is it that a certain flight maneuver would cause SD card writing issues?
2-10 14:30
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schl0r
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https://www.youtube.com/watch?v=6FQbWWaEHxU  

This might help. I haven't used a cap so far and ordered a bunch.
2-10 16:05
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GeoffGFPV
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schl0r Posted at 2-10 16:05
https://www.youtube.com/watch?v=6FQbWWaEHxU  

This might help. I haven't used a cap so far and ordered a bunch.

I follow Furadi. Awesome FPV pilot. His video gives a great explanation on using caps on his builds especially for his HD builds due to high voltage spikes. I will mostly like put an extra cap on the 9v pad that feed power into my DJI air unit and continue to use a cap on the battery power leads which has been common practice for my builds in the past. Thanks for the link.
2-10 19:44
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llbr22
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Flight distance : 253087 ft
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Maiden flight, not more then 200 yards away, same thing just happened to me. Recording on the goggles and air unit.

Subsequent flights were fine but I kept it close and flew easy since it’s a new build.

I’m definitely going to try not recording on the air unit.
2-14 07:02
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GeoffGFPV
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llbr22 Posted at 2-14 07:02
Maiden flight, not more then 200 yards away, same thing just happened to me. Recording on the goggles and air unit.

Subsequent flights were fine but I kept it close and flew easy since it’s a new build.

Glad you were able to save your quad especially on your maiden. Until this gets all sorted out, I agree that I will not be recording on my air unit for now and just record on my DJI goggles.
2-14 21:13
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llbr22
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Update: I was doing some range testing today, and I got approx. 1/4 mile away, full LOS, then video froze and I got a failsafe. this is WITHOUT the SD card in the Air Unit. I was at 700mw.  I don't think this i a very RF heavy environment, but not totally sure.

I'm pretty sure the first time it happened, I flew over a hill crest and that probably affected it a bit, but I was only 200 yards away.

Should I see more picture breakup, or my bars drop to 2 or 1, or Mbp speed drop down to under 20 before I lose signal? None of that happened.

My setup
GepRC MK4 HD5 Frame
6S
iFlight SucceX-D F7 stack for DJI HD
iFlight ZING 2208 1800Kv
DJI controller


2-18 11:43
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GeoffGFPV
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llbr22 Posted at 2-18 11:43
Update: I was doing some range testing today, and I got approx. 1/4 mile away, full LOS, then video froze and I got a failsafe. this is WITHOUT the SD card in the Air Unit. I was at 700mw.  I don't think this i a very RF heavy environment, but not totally sure.

I'm pretty sure the first time it happened, I flew over a hill crest and that probably affected it a bit, but I was only 200 yards away.

Interesting. We have a very similar set-up even up to the point of using 6s batteries. That is the problem with the DJI air unit with its built-in vtx and rx. You can lose both rx signal and video signal at the same time and you can lose total control of your quad with no video or stick inputs. I have a build that will have a TBS crossfire nano for rx using RSSI and LQ for Telemetry on OSD to avoid getting a failsafe in the future which can determine RF heavy environments. I will still have builds using DJI only HD FPV system and continue to monitor for updates from DJI.
2-19 19:25
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cusglider
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Flight distance : 4025801 ft
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llbr22 Posted at 2-18 11:43
Update: I was doing some range testing today, and I got approx. 1/4 mile away, full LOS, then video froze and I got a failsafe. this is WITHOUT the SD card in the Air Unit. I was at 700mw.  I don't think this i a very RF heavy environment, but not totally sure.

I'm pretty sure the first time it happened, I flew over a hill crest and that probably affected it a bit, but I was only 200 yards away.

"I flew over a hill crest "

Please remember that any radio will have problems once you drop beyond the horizon and lose LOS. So just don't provoke critical situations.

"6s"

Without special power supply the air unit rules out using 6s. In doing so anyways you take risks that are avoidable.

"RF heavy environment"

Keep an eye on the data transmission rate of the air unit (lower right on the screen). If the M/bit rates drops significantly below 10 M/bit it helps to look for "safer ground" and get out of this zone.

Usually the picture quality is so fascinating that it easily makes you cross the limits without being aware of it, until the connection breaks ...
2-20 12:21
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Cobaki
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Switzerland
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Same issue for me. Happened on several occasions, with and without an SD card in the air unit. Also flying 6S on a T-motor F7 stack (with a cap) and 1700kv Lumenier motors. Mostly happens during hard maneuvers like flips - but not exclusively. Holding back on any long range stuff because I'm afraid of losing my quad. I can get in twenty flights without an issue and then suddenly, video gone and failsafe as close as 30 meters away from me. There a lots of videos on youtube with people having the same issue.  
2-21 05:12
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djiuser_bXU91VVpTjDr
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United States
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I got full dji setup with kakute f7 board and two failsafes at about 60 yards luckily on a grass field, I'm experimenting with antenna spacing ,dji says 4 inches apart,so far better signal and hopefully stay flying
2-26 17:42
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llbr22
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Flight distance : 253087 ft
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cusglider Posted at 2-20 12:21
"I flew over a hill crest "

Please remember that any radio will have problems once you drop beyond the horizon and lose LOS. So just don't provoke critical situations.

Thanks for the responses. My replies:
"Please remember that any radio will have problems once you drop beyond the horizon and lose LOS. So just don't provoke critical situations."


It continues to happen. without provoking by flying with obstructions.

"Without special power supply the air unit rules out using 6s. In doing so anyways you take risks that are avoidable."



My setup:
GepRC MK4 HD5 Frame
6S
iFlight SucceX-D F7 50A ESC stack for DJI HD BEC: 5V 2.5A / 9V 2.5A Input voltage:recommended 2-6S, MAX 8S
iFlight ZING 2208 1800Kv
DJI controller
Current DJI firmware

"Keep an eye on the data transmission rate of the air unit (lower right on the screen). If the M/bit rates drops significantly below 10 M/bit it helps to look for "safer ground" and get out of this zone."
See this video where it happens at 51 seconds. It never drops below 25Mbps
[color=var(--ytcp-link-color)]

I'm pretty sure there's a problem though with the power regulator and iflight is sending me another board to try. I just added a capacitor large enough for 6s (50V), so let's see if that fixes it. Unfortunately, I'm having intermittent problems keeping the DJI Air Unit in communication with the flight controller (ugh!)  




2-26 20:55
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