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No Signal problem in the middle of the flight
6097 27 2015-7-13
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Phantom Menace
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United States
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I have a P3P and I do have the firmware upgrade to 1.2.6. I was flying and everything was working fine. I was about 3500 feet out and started to get weak transmission messages. This is normal as I live in a valley with lots of trees and hills as obstructions.

then the weak transmission signal turned into a "No Signal" message.

Assuming that if the aircraft lost the signal for more than a few seconds, it would return to home, I waited. The return to home signal did not kick in. Then I thought, if there truley was no signal, then it couldn't tell me it was returning to home, so I waited again. Nothing, then I moved the drone around, I went up in altitude and started bringing it back towards me. I saw the video feeding back to me. I was in perfect control of the aircraft and could watch the streaming video and fly it back to myself. I hit the return to home button, and it started beeping as it should, and the message came up that it was returning to home. In the video feed, I could see it turn and start comeing back.

So everything was working fine and as it should. I had a connection, I could see the video and all the features were working.

My issue is that there was still a bright red error message that said "No Signal" even though it was quite clear that I havd a perfectly good signal.

What is going on there?

I have not flown it since. This was just last night, but it does reduce the level of trust I have in it, when I get a contradiction like that.

Anyone else experiencing this?

2015-7-13
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ancientman
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Flight distance : 524081 ft
United States
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Are you using ios device? I too have same problem once when I did not see 'Trust this computer' sign when I connect my iphone 6+.
2015-7-13
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Phantom Menace
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No, I am on Android, using the google Nexus 7 ii tablet. I am running the latest DJI Pilot app and firmware version 1.2.6 on my P3P.
2015-7-13
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ancientman
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Flight distance : 524081 ft
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As you see, it flight log in iphone shows my P3P stopped on middle of ocean. However, I was able to control it without phone(tablet) connection which shows 'No signal' to retrive it back.
After restart both machine(controller/P3P), never happen again. Of course flight log was missed from end of below log to landing. It was extremely scary experience to me though....

Also, I found This never happen if I clicked 'yes' when 'Trust this computer' sign showed up when I connect my iphone to controller initailly.

Should I pull out flight log from P3P itself to verify situation at the moment?
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2015-7-13
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kiwichrish
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New Zealand
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Sounds like you lost the video feed, but not he R/C link.. I've had that happen a couple of times in built up areas, I assume due to interference.

The thing to do is check the status LED on your transmitter, it tells you the status of the far more important control link..  The app on your Android has nothing to do with flying the Phantom, it's just a pretty way to view information it sends back and change settings...  

A couple of weeks ago I had one time where I was only 100m away, 120m up and I lost the video link...   I got back down on the ground 2m in front of me before the video link returned.  I decided that was a bad spot to fly and packed up..  Another time I had to power off the P3 and turn it back on, so some sort of software glitch on the P3 dropped the link maybe?  Not sure..  But the control link and telemetry side of things has always been solid.

Cheers, Chris H.
2015-7-13
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Phantom Menace
lvl.1

United States
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I guess it's something that might get fixed in a future upgrade. It is nerve wracking, however, especially if you're over water or miles of forest. I just want to see what's going on out there.
2015-7-15
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suqsid.bobmail
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United States
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Phantom Menace Posted at 2015-7-16 09:09
I guess it's something that might get fixed in a future upgrade. It is nerve wracking, however, espe ...

It means the app doesn't have a usable signal.

Look at the light on the remote to see if the RC is still linked to the drone.

If the light is green, the remote is still linked. The RC will still work so you can use the RTH button if you want.

If the RC light is red, the link is broken and it will automatically RTH.
2015-7-15
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Phantom Menace
lvl.1

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Please help me to understand something. The way I thought that it worked was that the only thing with an antenna is the remote. The app sees the remote through the USB connection and draws it's info about connection status, telemetry and everything else from the remote. So if the remote was still connected, and the tablet is still plugged into the USB port, how can the app think there is no connection? It doesn't also connect to the drone independently.

Am I explaining this right, or is that not the way it works?

It still sounds like a glitch in either the app or the firmware that is causing the erroneous message, as the only source for the information displayed in the app is the remote, unless I am wrong.


2015-7-16
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PhantomAtAK
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United States
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Phantom Menace Posted at 2015-7-17 00:01
Please help me to understand something. The way I thought that it worked was that the only thing wit ...

I see it as two separate things being transmitted:

1) Flight instructions are sent to the Phantom from your R/C controller.  In theory (haven't tried it), you can fly your Phantom, with just the controller, and the Phantom.  The tablet/phone with app is not needed to fly if you want to take a line of sight flight.  

2) Visual information is handled by Lightbridge.  It has a separate signal than flight instructions, and is the component that is giving you trouble in flight.  So, if you lose video link, no big deal if you can fly line of sight, or hit RTH if it is out of sight.  P3 is still being fully controlled by your RC inputs, even though you are spooked by the loss of video telemetry.  

If you lose RC link vs Lightbridge (video), RTH should auto initiate, and P3 flies back to you.
2015-7-16
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rdc44444
Second Officer

United States
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Yes the same exact thing happened to me after upgrading to the latest firmware. I lost video feed and had "no signal" in red. I waited expecting return to home to kick in. I noticed the battery % was dropping however the distance wasn't changing so I hit RTH on the controller and it came back home after a few minutes. It was scary because I was 400 feet high and close to 4000 feet out when the video signal dropped and at first I wasn't sure what was happening. I received no warning like "weak transmission signal" and it never re-established video connection even though i tried shutting down the app and restarting it.  I landed it and took off with a fresh battery and didn't have any further problems. I've flow about 15 times with three different P3's without experiencing the same problem so I'm hoping if it is a firmware/app bug it doesn't happen very often.  
2015-7-16
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Phantom Menace
lvl.1

United States
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Thank you PhantomAtAK. I still think it's a bug. I understand that Lightbridge is a separate system, but I believed that it, along with the controller info were both being transmitted together in one signal. If that were true, you couldn't lose one without losing both. I could be wrong here and it would be great to have DJI chime in here and set me straight with some actual specs.

Even if that is not the case, and they are two separate transmission, both with different range capabilities (Which seems kind of foolish, really) it doesn't explain the blanket statement the warning makes when it says "NO SIGNAL". It doesn't say NO VIDEO SIGNAL or anything specific, and it also doesn't reconnect when you come back within range, which seems strange.

There also seems to be no set distance at which it happens. I have had it happen at less than 1000 feet, and other times, not until I was more than 3 miles away.

Fortunately, as you say, I seem to still be able to control the drone with the RC unit, even if I lose the app and video link, and it does properly RTH when requested, or when the battery is low, or  when the controller is off or out of range. I am not as nervous about losing the drone, but it really looks like a bug in either the app or firmware.

I haven't flown without the app from the beginning of a flight, but twice now, the app has crashed and I have had to restart it and once I shut the tablet completely off and flew the drone back and landed it, so it seems to not be required for flying line of sight. However, if you are filming and you want an idea of what is in your frame, it's hard to fly without it.
2015-7-18
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mtnmaddman
Second Officer

United States
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I am pretty sure that it is the video link notice after it stutters weak transmission it locks up, mine did this also before I sent it back It did it after the latest firmware and pilot app update. I associated it more with when I upgraded the pilot app.  really irritating.  Note: I didn't send it back because of this, I just sent it back and got an Inspire.  It was the shell cracks, along with everything else that did me in on the p3 I will buy again if they straighten some of these problems out.
2015-7-18
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mtnmaddman
Second Officer

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Phantom Menace Posted at 2015-7-18 22:35
Thank you PhantomAtAK. I still think it's a bug. I understand that Lightbridge is a separate system, ...

Its the return picture link try this http://forum.dji.com/forum.php?m ... 5&fromuid=17178
2015-7-18
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Phantom Menace
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mtnmaddman Posted at 2015-7-19 05:35
Its the return picture link try this http://forum.dji.com/forum.php?mod=viewthread&tid=23565&fromu ...

Sorry, I don't understand why you linked to the post about an antenna booster in this thread.
2015-7-19
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lb11778
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Flight distance : 368842 ft
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how can you even see the from that distance? I thought we are supposed to keep it with in sight when flying in the US?
  I have not dared go that far with mine yet because of this happening.



2015-7-19
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mtnmaddman
Second Officer

United States
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Phantom Menace Posted at 2015-7-20 06:19
Sorry, I don't understand why you linked to the post about an antenna booster in this thread.

Pretty simple if you increase the signal strength for the video link you wont necessarily get the weak signal that finally morphs into the app freeze.  worked for me.
2015-7-19
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Phantom Menace
lvl.1

United States
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I was already flying with an antenna mod from FPVLR. (https://fpvlr.com/store/product/phantom-3-advanced-antenna-kit/) Sorry I didn't mention that. But in any case, it still seems wrong for it to be saying No Signal while I can still view the live video stream and control the bird. It has to be a bug in the system. If I can see the live video feed and control the drone then I do actually have a signal and if it says I don't, then it is a bug.

I can believe that I momentarily lost the signal, but once it recovered, it should no longer be saying No Signal.

It also should not be so vague. If it means lightbridge, or the video signal only, it should say VIDEO LINK LOST. If it means the controller is not connected, It should say RC LINK LOST, and the RTH should be activated. The RTH was not automatically activated when I got the "NO SIGNAL" message, so again, there was a signal.

Booster or not, the message is an error or at the very least, the message not resolving once the link is re-established is an error and needs to be corrected. I continue to write in hopes that people from DJI might see this and work on resolving this annoying problem.
2015-7-20
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nightrider1383
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I had a similar issue occur. I do believe this is a bug. My sudden loss of signal happened when I switched from Video to Photo shooting (using the slider on the right-side of app; above circle capture button), I'm a iOS user.
Hasn't happened again, but definitely scarey situation. Luckily the UAV was directly above me, about 100 feet in the air, no obstacles, and being at the beach. That's why I think it's a software issue. Hopefully they resolve, or at least investigate.
2015-7-20
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PhantomAtAK
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Phantom Menace Posted at 2015-7-20 20:52
I was already flying with an antenna mod from FPVLR. (https://fpvlr.com/store/product/phantom-3-adva ...

Amen.  I would love more clarity in the notification.
2015-7-21
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Phantom Menace
lvl.1

United States
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I sent DJI the following email regarding both gaining a better understanding of how the RC signal and video signal are transmitted, and why I keep getting the No Signal error even while I can see see the signal and control the drone.

This is the email I sent:

I have two issues I would like some guidance and information on.
First, please set me straight where I am wrong. I am trying to get a solid understanding of how the signal is transmitted between the controller and aircraft on a Phantom 3 Professional.
My understanding is that with the Phantom 3 and integrated camera, There is only one single transmission at 2.4 GHz that is an integrated transmission consisting of both the RC control and the Lightbridge technology which sends me back the live video feed.
I am therefore confused when the video signal starts to break up or is lost, and I still have all the bars indicating a strong RC signal. If they are an integrated signal, how can I lose the video while still having a strong RC signal?
If they are two separate signals, aren’t they at different frequencies? (2.4 GHz for RC and 5.8 GHz for Lightbridge)
Or are the two antennas on the controller separate? One for Lightbridge and the other for RC? If that is true, are they both the same frequency (2.4 GHz)? And if that is true, why would they have different ranges? Wouldn’t it make more sense to have them both have the same range? What point is there to be able to fly further than the video feed works?
Please explain the actual transmission process and frequencies and why there is a disparity in the range of the two transmissions.
In a related question, I have been getting “No SIGNAL” warnings while flying once I get out a ways. I’m not sure what that means, since it does not force a RTH, so there must still be a connection. My signal strength for the RC is at full. I sometimes momentarily lose the video feed just before I get this warning, but I recover the video feed and the warning does not go away.
it seems wrong for it to be saying ‘No Signal’ while I can still view the live video stream and control the bird. It has to be a bug in the app or firmware. If I can see the live video feed and control the drone then I do actually have a signal and if it says I don't, then it is a bug.
It also should not be so vague. If it means lightbridge, or the video signal only, it should say VIDEO LINK LOST. If it means the controller is not connected, It should say RC LINK LOST, and the RTH should be activated. The RTH was not automatically activated when I got the "NO SIGNAL" message, so again, there was still a signal.
It seems that the message is an error or at the very least, the message not resolving one the link is re-established is an error and needs to be corrected. I was hoping you could tell me if DJI was aware of this and are working on it.
Could be coincidental, but I never noticed this before upgrading to the latest firmware, v. 1.2.6
Thank you,
Bob Robertson


This was their response:

Dear Robert,
Thank you for contacting DJI Technical Support.
The video signal and control signal are two separate signals, and using same antennas.
Both the video signal and control signal are using 2.4Ghz Frequency, while on different frequency band.
'No Signal' refers to the video signal.

If the control signal lost, it'll show 'RC signal lost' on the APP screen.

For the live video issue, please read the post below for suggestions:
http://forum.dji.com/thread-23241-1-1.html

Thank you for choosing DJI.
Best Regards,
Sophie

This answer did have some useful information in it, but was incomplete as it did not address why the No Signal Error would pop up when I still had signal or if I temporarily lose the video signal and then it comes back, why the NO SIGNAL message does not resolve and go away.

They did refer me to their apology post regarding Firmware, which leads me to believe that the error showing up erroneously, and not resolving is probably linked to problems in the latest firmware.

At least I now know that the error "NO SIGNAL" only refers to video signal loss, and I shouldn't panic. If I don't have eyes on the drone, I can always hit RTH and it will get the signal. If RC signal is lost, the error message would specifically  say, "RC SIGNAL LOST".

Personally, I believe instead of saying "NO SIGNAL" it should say VIDEO SIGNAL LOST", but maybe that's just me.

I just hope that these issues are cleared up in the next firmware release.

2015-7-24
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Highlander Brow
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Spain
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Yesterday, I faced apparently the same problem. I am IOS user. Phantom 3 PRO, flying gently in a open area. No issues at starting up, getting appropriate gps etc.. But then, during second battery, I got the first NO SIGNAL message, when P3 was just few feet high and 100 feet distance.  Empty video scree. The scary thing is that gps signal looked lost too, and everyhing else, actually as if there was total collapse of the system. I re started the application. And i recovered everything and landed with normality.  At the end of the third battery when i was about 100 feet height and  400 feet distance, I  had again RED message of NO SIGNAL. The video screen was blank. Apart from the fact that I was seeing  P3 just in front of me and it made no sense the loss of video signal what actual turned me into panic mode again was that all gps signal, video signal were gone on the screen. It either looked as i have lost video signal and  P3 has lost gps. Scary.  I pushed the rth button and it came back straight and when approach from landing it recovered everything and landed it manually. It was the first time i used my iphone as a hotspot to complete the map cachet of the area, then i switched off and put the mobile away as i always do. It was also the first time that i switched off the wifi of the ipad air (following the manual recommendations) after more than nine hours flying during seven weeks without any trouble. I have checked the log and in neithe case s it is reported a gps loss nor nothing abnormal.  It looks to me that  the app crashed and lost connection and information from the control unit.  I will make some flhts today and checked if it happens again.
2015-7-24
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droneflyers.com
First Officer
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Mine does that regularly but the other day I selected a custom channel (20) and it seems to stop doing it.

I'd say to give that a try.
2015-7-25
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pmarsh2802
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United States
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I am an iOS user with a phantom 3. I have had this same situation particularly at start up. There is most definitely a bug in the DJI software. If the signal disappears on the iPad for more than 15-20 and you have line of site and carol of drone it seems safe to disconnect the iOS cable and plug it back in. The signal and everything pops back up. Nerveracking but it's worked at least a dozen times in multiple locations with no issues.
2015-7-25
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Iflewbyyou
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I've had this same issue many times since the last firmware upgrade, so it must be related to Firmware v1.4.0010.  My problem has even exceeded "no signal".  One day I was about 600 feet away at an altitude of about 150 feet.  I had a week signal and a few brief "no signal" messages. I was bringing it home when suddenly, I saw the most frightening message; "disconnected" in red (WTF !?!).  I had no video signal, and apparently no control. I waited and waited for it to return to home.  Eventually, it did come toward me.  I then decided to move the sticks even though it still said "disconnected" in red.  To my surprise, I was still able to control it in every way, but was not able to stop return to home, it was hell bent on landing.  That was fine, I had launched in the middle of a parking lot, so the landing was just fine, and I wanted it on the ground and safe!  But it was a set of circumstances I have never seen before, and never want to see again. The recorded flight path ended where the disconnect first occurred, it showed no return path home!  There is definitely a glitch in Firmware v1.4.0010.  Is that the same version you guys had at the time of your worst problems?
After pondering it for a week or two, one theory is that the "disconnected" was actually a different problem from the frequent breakup of the Lightbridge signal I have experienced since installing v1.4.0010.  That is the problem that persists, I suffer with it every day, whether in airport mode or not.  But the "disconnected" could have been due to the USB cord to the iPhone not being firmly seated at either end of the cable. I wish I had had the presence of mind to look at the diode on the remote control to see if it was green or red, I do not recall doing that. I was in a bit of a panicked state. So I may never know. Just thought I should offer this second possibility.  Still, the breakup of the Lightbridge video feed is real, it is chronic, and it didn't happen much for me, until I installed v1.4.0010.  It can happen when the remote and the P3P are 3000 feet apart, or when they are 3 feet apart.
2015-10-22
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Shon.white
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United States
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contact dji mine did the same thing and crashed and was destroyed, their phone number is 818-235
2015-10-22
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Shon.white
lvl.2

United States
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sorry, 818-235-0789 let them know
2015-10-22
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Iflewbyyou
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Thanks Shon.white!  I may do that, but it is the persistent Lightbridge video feed breakup that bugs me most. I've edited my above post to include a theory I came up with, which might explain the disconnected message. I have not seen "disconnected" again in the approximately two weeks since, so I think it was anomalous and possibly a one time thing. If it happens ever again, I will check the diode on the remote, and will push both ends of the iPhone cable in firmly, as that may explain the iPhone reporting a total disconnect while the aircraft was still flyable by the remote.
2015-10-22
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Geebax
Captain
Australia
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Phantom Menace Posted at 2015-7-25 00:21
I sent DJI the following email regarding both gaining a better understanding of how the RC signal an ...

"Personally, I believe instead of saying "NO SIGNAL" it should say VIDEO SIGNAL LOST", but maybe that's just me."

I agree with you, the message is far too vague, and from the posts on this forum, you are not the only one to experience this. DJI should make it clearer as you suggest.
2015-10-22
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