As above. If loss of video feed, is the map still getting updates from the ac?
Thanks

Do you mean telemetry?

WilliamM Posted at 2017-2-12 14:00
Do you mean telemetry?

Well yes and the map google/here. I would think they are via the controller(5.8) but not sure.

The maps come from your phone or tablet, not from the aircraft. You can lose the video feed, but still have full control of the aircraft and receive information back from it, in cluding positional data, so you can see where it is.

stuka75 Posted at 2017-2-12 16:57
Well yes and the map google/here. I would think they are via the controller(5.8) but not sure.

Telemetry, (altitude, distance, battery level, GPS position) are all via the wifi signal @ 2.4 GHz downlink from the AC. That's the same band as the video, but it's a different data stream. So video could go out and telemetry could still be displayed at the same time. But in reality they both cut out at about the same time, give or take.

Is there documentation of the WI-FI signals used in the Phantom 3 Standard?  I understand there are two bands, one for control of the Phantom and the other for video/photo link.  I can see that there are two flat 2.4GHz antennas inside the controller and one 5.8 GHz (?) on the outside.  Would really like to read about what they do and how DJI uses them on the Standard model.

WilliamM Posted at 2017-2-12 18:23
Telemetry, (altitude, distance, battery level, GPS position) are all via the wifi signal @ 2.4 GHz downlink from the AC. That's the same band as the video, but it's a different data stream. So video could go out and telemetry could still be displayed at the same time. But in reality they both cut out at about the same time, give or take.

So you would loose positional inof on the map around time the video stream becomes compromised even though you have aiarcraft control?
thanks

stuka75 Posted at 2017-2-12 19:46
So you would loose positional inof on the map around time the video stream becomes compromised even though you have aiarcraft control?
thanks

Yes, but that seems to be limited in time from my experience. Meaning it seems that the app only permits the telemetry to be out for a short time before it assumes the control must be out also. As the RC has no data to confirm the AC is still connected. This is not documented anywhere, it's just from my experience that the lose of control is never far behind losing the video/telemetry before RTH starts.

Regarding the 2.4 and 5.8, they are two completely independent signals.  One has no relationship with the other at all.  

If you're heading straight out and you lose 2.4, the screen will freeze and you may or may not have control via 5.8.  You likely do have control early on, but you have no way of knowing unless you have a live tracker which is also completely independent.  So without a live tracker, you are flying blind.  Obviously, as you head further out, you'll eventually lose control but, again, you need a live tracker to know exactly when.  There is no relationship between when the AC begins RTH and when you lost the 2.4 connection.  The only thing that matters is the 5.8 connection.  Technically, if the 5.8 control signal was strong enough, you could fly for 20 miles or more with no 2.4 connection.  In fact, you could fly 20 miles or more without even powering up your mobile device.  You could even disable the 2.4 transmitters on both ends completely and the AC could still fly just fine.

The 5.8 is very simple.  It is the control signal and nothing else.  It shoots out from the controller and is received by the AC.  As long as the 5.8 ghz signal is being received by the aircraft, it will fly.  That's all there is to it.

The 2.4 is very complex which is why it usually drops out first - because there are so many things that can go wrong.  2.4 takes care of video and telemetry.  Both the controller and the P3S have transceivers with a switching mechanism and then two antennas connected. Each of the two antennas does the same job, but they to it one at a time and switch between each other automatically in a constant effort to get the best connection. But that's just the beginning.

It's a very complex process which allows the system to work. For example, in order to see video on your mobile device, the bird must transmit an image, the controller must receive it, the controller then sends data back to the bird called a checksum. The bird then receives the checksum and sends yet more data back to the controller to either confirm or deny whether the data sent the first time was correct, and then, finally, if the data is correct, the controller sends the data to the mobile device on yet another 2.4 frequency (and this whole checksum process may very well go again between the mobile device and controller).

Yes, it's possible to lose video and still have telemetry and vice versa.  This is more obvious on the trip back.  As your AC gets back into range, 2.4 will normally return.  But sometimes the video will crash (freeze) and not return regardless of your range and yet your telemetry still works fine.  Typically as the AC comes into range, you'll see the FPV try to update, the FPV screen will change slightly, and then it will freeze again and not come back.  But you'll see your telemetry is working.  Less often, the telemetry will crash and not return, but your FPV works fine.  But most of the time, both will return normally as you fly back into 2.4 range.  Every once in a while, your flight app will crash completely and you will either have to reload the app or even reboot the mobile device while the AC is in the air.  But remember - none of this has anything to do with the AC.  It's advantageous to have a solid mobile device with lots of memory to minimize these problems.  It's also advantageous to have a live tracking device so that you can monitor your aircraft's position, altitude, speed, battery, etc. as it flies regardless of its range.

Remember - flying out of LOS is not legal in the U.S.  

Hope this helps.

WilliamM Posted at 2017-2-12 20:25
Yes, but that seems to be limited in time from my experience. Meaning it seems that the app only permits the telemetry to be out for a short time before it assumes the control must be out also. As the RC has no data to confirm the AC is still connected. This is not documented anywhere, it's just from my experience that the lose of control is never far behind losing the video/telemetry before RTH starts.

Wrong sorry ..... the video and telemetry can be out for an entire flight in fact ...

I've flown my P3S for many minutes with 'dead video / telemetry' accepted its been within sight and I can have good idea of flight pattern. But still the video / telemetry was dead.

The two are completely independent EXCEPT for one thing .... FLIGHT Commands from the screen that you tap are transmitted to Controller by 2.4, converted in controller to be sent as 5.8 signals ... such as TAKE OFF .... RTH ..... LAND. They basically trigger the controller to send the 5.8 commands for them.

Nigel

Magic Power - more dbs for who know!

solentlife Posted at 2017-2-14 12:33
Wrong sorry ..... the video and telemetry can be out for an entire flight in fact ...

I've flown my P3S for many minutes with 'dead video / telemetry' accepted its been within sight and I can have good idea of flight pattern. But still the video / telemetry was dead.

Don't think so, every time my telemetry goes out the RC control signal is not far behind. I've also read many post/threads that state the very same. How else would the RC know to change it's large LED from green to red (connected vs not connected). That LED is the indicator of what the remote thinks the status of the control 5.8 GHz signal is. And since the 5.8 GHz signal is only a one way transmission, there is no other data inbound to the remote, except for the 2.4 GHz signal which is two way. You might think the video (FPV) and telemetry is out, but I bet it's just the video and the telemetry is still being feed to the remote.

Mark The Droner Posted at 2017-2-13 03:45
Regarding the 2.4 and 5.8, they are two completely independent signals.  One has no relationship with the other at all.  

If you're heading straight out and you lose 2.4, the screen will freeze and you may or may not have control via 5.8.  You likely do have control early on, but you have no way of knowing unless you have a live tracker which is also completely independent.  So without a live tracker, you are flying blind.  Obviously, as you head further out, you'll eventually lose control but, again, you need a live tracker to know exactly when.  There is no relationship between when the AC begins RTH and when you lost the 2.4 connection.  The only thing that matters is the 5.8 connection.  Technically, if the 5.8 control signal was strong enough, you could fly for 20 miles or more with no 2.4 connection.  In fact, you could fly 20 miles or more without even powering up your mobile device.  You could even disable the 2.4 transmitters on both ends completely and the AC could still fly just fine.

Nice reply. Thanks for sharing. Question is whether or not P4P. I2 have video tx on 5.8 GHz as well.

Know that your P4P is unlike any other Phantom in that it can switch its Lightbridge signal from 2.4 ghz to 5.8 ghz.

My post stemmed from the P3S conversation.  So nothing in the post has anything to do with the P4P.

The P4P uses Lightbridge which is not a wifi system.  Even if it uses the 2.4 frequency, it's still not considered wifi because Lightbridge is so different and proprietary.  I think "advanced" is a good adjective to describe Lightbridge.  My understanding is that Lightbridge uses two frequencies, but they are both in the same frequency band.  So on your controller, each of the two antennas sends a different signal even though they are on the same band.  And yet, they don't interfere due to the nature of the signals.  Also, there isn't a two-way check as there is with the wifi, which in effect makes it simpler and promotes longer range.  So, as I understand it, if you switch from the 2.4 band to the 5.8 band, both control and FPV/telemetery switch to the 5.8 band.  

That's my understanding anyway.  :-D  

As said - I have physically flown my P3S with 2.4 signal failure for more than just a few minutes. I have had the model out significant distance and flown back visually all the while with 2.4 failed. This is before I started my testing phase and actually is one of the reasons I started doing so many tests.

Lets give an example of where the app used influences flight. Go uses the battery telemetry to decide flight or not. You can have GO refuse to fly but Litchi will. Go using the data feedback from the model on the 2.4 telemetry. Litchi receives same data feedback - but says you can fly. You fly - all is fine. Litchi is not ignoring or creating unsafe situation.
It is similar to switching of the tablet / phone ... but its the APP deciding not the model whether flight or not.

The 5.8Ghz signal only needs to be one way as it has no need whatsoever of feedback ... it works on same idea of commands sent to model as any other RC model. The 2.4 is there to provide feedback to the App and to you as pilot. The 5.8 couldn't care less ...

As I say - the interraction of 2.4 to 5.8 is purely in the controller when tapped commands are converted to 5.8 command signals sent out. THERE ARE NO FLIGHT commands via 2.4 antenna to the model. It is purely video / camera / telemetry relay on 2.4.

Think of another item ... model gets out to limits and initiates RTH ... can YOU do anything to that model ? Even though you may not have video / 2.4 link ? Yes of course you can - you can still climb / descend alter flight path ...  I've even swung the model round so it flies backwards to home ... with camera recording astern !!

Nigel

Mark The Droner Posted at 2017-2-13 03:45
Regarding the 2.4 and 5.8, they are two completely independent signals.  One has no relationship with the other at all.  

If you're heading straight out and you lose 2.4, the screen will freeze and you may or may not have control via 5.8.  You likely do have control early on, but you have no way of knowing unless you have a live tracker which is also completely independent.  So without a live tracker, you are flying blind.  Obviously, as you head further out, you'll eventually lose control but, again, you need a live tracker to know exactly when.  There is no relationship between when the AC begins RTH and when you lost the 2.4 connection.  The only thing that matters is the 5.8 connection.  Technically, if the 5.8 control signal was strong enough, you could fly for 20 miles or more with no 2.4 connection.  In fact, you could fly 20 miles or more without even powering up your mobile device.  You could even disable the 2.4 transmitters on both ends completely and the AC could still fly just fine.

I agree with most of what you said with this one exception. "In fact, you could fly 20 miles or more without even powering up your mobile device.  You could even disable the 2.4 transmitters on both ends completely and the AC could still fly just fine." On the first half of that statement, well of course you could. The device screen is our why to view the data/image, the wifi 2.4 signal is still being received by the remote even with the device turned off.  Now on the second part about being able to physically disable the wifi signal in some way, that's completely just theoretical as no one has every really done that. Now if you can do such a thing and maybe install a set of "Termination Loads" on each of the wifi ports on the P3S, assuming the stock internal wifi panels are also disconnected. Then go fly out to the normal full range for your Phantom, you would have proved me wrong. Until than it's just theoretical in my mind.

solentlife Posted at 2017-2-15 01:29
As said - I have physically flown my P3S with 2.4 signal failure for more than just a few minutes. I have had the model out significant distance and flown back visually all the while with 2.4 failed. This is before I started my testing phase and actually is one of the reasons I started doing so many tests.

Lets give an example of where the app used influences flight. Go uses the battery telemetry to decide flight or not. You can have GO refuse to fly but Litchi will. Go using the data feedback from the model on the 2.4 telemetry. Litchi receives same data feedback - but says you can fly. You fly - all is fine. Litchi is not ignoring or creating unsafe situation.

I'll make one point here and have two questions. First the point, the device screen is our why to view the data/image, the wifi 2.4 signal is still being received by the remote even with the device turned off. So you said "all the while with 2.4 failed". First question, how would you really know the remote is not still receiving some of the telemetry (even if it's just a confirmation of the control signal being ok) in the background. The only thing you really know is your not seeing it displayed on the device screen.  Second related question, you nor Mark answered that one intriguing question I asked. How would/does the RC decide if the large LED should be green or red (connected or disconnected control)? As the 5.8 signal is only a one way transmission , as both of you have said and I agree. But for the data coming via the wifi 2.4 signal? And if you agree to that premise than if the 2.4 truly does go out, that LED light has no chose but to turn red indicating that the control signal is disconnected when in fact it may not be. I think there is one part of the telemetry data that we only see via the large LED on our remotes (red vs green) and even though the FVP and our telemetry data displayed on our screen might go out, it's this one hidden piece of data within the wifi signal that might still hold on a bit longer to confirm a control connection. And this is why you still have flight control without visual telemetry.

My first drone was a HAK909.  It was just a toy.  No FPV.

When I got the P2V, I didn't use my app for the first ten days or so.  I just concentrated on learning how to fly my new Phantom.  

Since the P3S is really just an advanced version of the P2V, and since the P2V can fly just fine with no 2.4 signal coming from the controller (i.e. the 2.4 transmitter is turned off), it's logical to assume the same with the P3S.   

In addition, there are those who have complained about the P2V+'s 2.4 transmitter on the bird burning out prematurely.  It's a major issue on that particular Phantom.  But I haven't read that this grounds the bird.  

You ask how does the large LED decide to be green or red.  It's part of the telemetry.  The AC knows if it has a signal or not.  How else would it give you the control signal strength?  How else would it know when to Fail-Safe?  The 5.8 connection info is broadcast to the pilot via 2.4.  I'm not sure why this confuses you.

Typically when the 2.4 goes out, the screen freezes.  So whatever had been displayed before is still displayed.  The only indicator that is actually live and correct is the 2.4 signal strength indicator.  I don't use Go, but on Litchi, the 2.4 signal strength indicator will show one red bar indicating extreme weakness and then nothing indicating no signal.  Anything else showing on the screen at that point is meaningless.  

Hope this helps.

Mark The Droner Posted at 2017-2-15 09:58
My first drone was a HAK909.  It was just a toy.  No FPV.

When I got the P2V, I didn't use my app for the first ten days or so.  I just concentrated on learning how to fly my new Phantom.  

Your lines: "You ask how does the large LED decide to be green or red.  It's part of the telemetry.  The AC knows if it has a signal or not.  How else would it give you the control signal strength?  How else would it know when to Fail-Safe?  The 5.8 connection info is broadcast to the pilot via 2.4.  I'm not sure why this confuses you."
Not confused at all, you just agreed with me to a point. Your agree the only way for the RC to know it's connected (control 5.8) to the AC is via telemetry data from the wifi 2.4 signal. Now hold that thought. And lets assume that the wifi signal goes out 100%, no data of any kind. How would the remote know if it's still connected (control @ 5.8) to the AC, it could not. As you yourself said that data is coming from the 2.4 signal that is no longer being received. So my main and only point I'm trying to make here is if the wifi signal goes down, the RC has no other option but to go RED and show it's disconnected (even if not) because the remote has no confirmation otherwise.. Now once it goes RED does the RC issue a RTH command via the remote itself because it "thinks" it's disconnected, even though it might not be?

First of all, I have flown for miles - literally - with no 2.4.  So I'm not guessing about what happens.  I know what happens.  I have done this hundreds of times.  I have a live 3G tracker.  That means I can fly all over town, zig zag all around, with no 2.4 connection.  I can and I do.  It's not a theory.  

How can the RC issue an RTH command if it has no 2.4 connection?  Are you saying the RTH command goes out via 5.8?  And if so, why do you think so?  Do you suspect there's some sort of computer inside the controller that receives this data and makes the decision?  And then some kind of RTH signal is sent via 5.8?  Is that it?  Or do you think the RTH command is sent from your mobile device?  How - if there's no 2.4 connection?  Help me out here.  

The controller doesn't care if it's connected or not.  The controller just transmits 5.8.  Whether the AC receives it or not - the controller doesn't give a hoot.  It's the pilot's problem, not the controller's.  

For the record, my "ready to fly" icon does not go red when I lose 2.4.  Why would it?  It doesnt' know whether I have 5.8 or not.  Why would it deliberatly try to mislead me?  What it does is freeze and show redundant data which is meaningless.  It shows zero bars for 2.4 which tells me 2.4 is out.  So at that point I know 2.4 is out, and 5. 8 status is unknown.  

So what do I do?  I keep flying!  Because I have a live tracker.  And it flies just fine.  

I have a friend who flew his P3S out 7 miles and brought it back safely.  You think he had 2.4 all the way out and back?

Mark The Droner Posted at 2017-2-15 12:51
First of all, I have flown for miles - literally - with no 2.4.  So I'm not guessing about what happens.  I know what happens.  I have done this hundreds of times.  I have a live 3G tracker.  That means I can fly all over town, zig zag all around, with no 2.4 connection.  I can and I do.  It's not a theory.  

How can the RC issue an RTH command if it has no 2.4 connection?  Are you saying the RTH command goes out via 5.8?  And if so, why do you think so?  Do you suspect there's some sort of computer inside the controller that receives this data and makes the decision?  And then some kind of RTH signal is sent via 5.8?  Is that it?  Or do you think the RTH command is sent from your mobile device?  How - if there's no 2.4 connection?  Help me out here.  

What kind of live tracker do you have? And thanks all for a lively discussion !

I use the Flytrex Live 3G.  They likely don't have one for your AC.  

Can I gate crash please? You guys obviously know quite a lot, and I've had no joy with Dji or elsewhere. During Follow Me the status lights usually go solid red on my AC and stay on until I switch the aircraft on and off again. It is the only function I use which required GPS, but I am getting 10-11 satellites shown in the Go App and no errors. Generally the aircraft does not follow me, but sometimes it does and sometimes even when the lights are red. Once the lights go red the aircraft will not usually respond to the controls, so I flip it back to P or Atti mode, where it will function perfectly. I am using latest firmware and 3.1.3 with Nexus 7 II tablet, though it did it with 3.1.1 as well; Follow Me never worked at all with 3.1.2, I guess because of the incorrrect position issue, so it would always say the aircraft was too far away to initiate Fllow Me even if it was a metre above my head :-).

Mark The Droner Posted at 2017-2-15 12:51
First of all, I have flown for miles - literally - with no 2.4.  So I'm not guessing about what happens.  I know what happens.  I have done this hundreds of times.  I have a live 3G tracker.  That means I can fly all over town, zig zag all around, with no 2.4 connection.  I can and I do.  It's not a theory.  

How can the RC issue an RTH command if it has no 2.4 connection?  Are you saying the RTH command goes out via 5.8?  And if so, why do you think so?  Do you suspect there's some sort of computer inside the controller that receives this data and makes the decision?  And then some kind of RTH signal is sent via 5.8?  Is that it?  Or do you think the RTH command is sent from your mobile device?  How - if there's no 2.4 connection?  Help me out here.  

You are still missing the point, take your time and re-read my post above. I'm taking about the RED LED on the remote, not the app display. I'm not going to retype the whole thing again. You frame of reference is your old P2V not a P3S, when talking about going out for miles without the use of a 2.4 wifi signal. So you have not really done this with a Phantom 3 than.  And it's doesn't need a computer inside the RC to trigger a RTH, nothing more than a 5¢ IC chip would do the job. The RTH command is already inside the RC, that's how come the RTH works when we do it with the S2 switch. Don't want to keep going back and forth with this, this is how I think it works until someone can explains in detail how the LED on the RC changes from green to red without the use a data from the wifi signal. Because if it's dependent on that 2.4 GHz signal, my point is valid.

WilliamM Posted at 2017-2-15 09:22
I'll make one point here and have two questions. First the point, the device screen is our why to view the data/image, the wifi 2.4 signal is still being received by the remote even with the device turned off. So you said "all the while with 2.4 failed". First question, how would you really know the remote is not still receiving some of the telemetry (even if it's just a confirmation of the control signal being ok) in the background. The only thing you really know is your not seeing it displayed on the device screen.  Second related question, you nor Mark answered that one intriguing question I asked. How would/does the RC decide if the large LED should be green or red (connected or disconnected control)? As the 5.8 signal is only a one way transmission , as both of you have said and I agree. But for the data coming via the wifi 2.4 signal? And if you agree to that premise than if the 2.4 truly does go out, that LED light has no chose but to turn red indicating that the control signal is disconnected when in fact it may not be. I think there is one part of the telemetry data that we only see via the large LED on our remotes (red vs green) and even though the FVP and our telemetry data displayed on our screen might go out, it's this one hidden piece of data within the wifi signal that might still hold on a bit longer to confirm a control connection. And this is why you still have flight control without visual telemetry.

How did I know ?

The main bar across top had a message stating clearly that Video / Wifi signal Failed .... also the RC LED was noted changed ... but what it changed to I honestly cannot remember. The matter I do remember clearly was the message on the top bar of the APP ... which had incidently near all greyed out apart from the red warning.

All of us have seen the CONTROL SIGNAL FAILED message .... but this one was a surprise to me ... I've only seen it a few times in all the flights ...

One was when I was flying over the area from my house ... another was over the town park.

Now I admit that I cannot state 100% it was total failure RC 2.4 to AC ... as you have no way to know that because you have no telemetry data at all displayed ... but the message was as I state above. A totally different wording to anything I'd seen before. I'd had video failure ... etc. before but not stating SIGNAL failed.

Nigel

Okay, sorry for the delay.  I was trying to get some input from my buddy and he is slow to respond so I finally just PMed the exhalted msinger over on pp (the man who knows more about DJI Phantoms than anybody on the planet), asked him, and here's his reply:

Yes, I do own a P3S. RTH is not initiated until the remote controller signal is lost for 3 seconds. It will not be initiated if only the downlink (Wi-Fi) disconnects.

Hope this helps.

Mark The Droner Posted at 2017-2-16 08:07
Okay, sorry for the delay.  I was trying to get some input from my buddy and he is slow to respond so I finally just PMed the exhalted msinger over on pp (the man who knows more about DJI Phantoms than anybody on the planet), asked him, and here's his reply:

Yes, I do own a P3S. RTH is not initiated until the remote controller signal is lost for 3 seconds. It will not be initiated if only the downlink (Wi-Fi) disconnects.

We know that ... sorry but his answer does not solve the later question of loss of 2.4 RF and flight commands continuing. We all know that RTH is triggered when 5.8 is lost for approx. 3 secs.

I already on other threads mentioned loss of video and app ... the tablet shut down in fact ... and the model just hovered waiting for me to give 5.8 command.
I restarted tablet and regained all control and completed the flight as I planned.

Nigel

I don't understand.  msinger wrote:

It will not be initiated if only the downlink (Wi-Fi) disconnects.

What about this sentence confuses you?  

Mark The Droner Posted at 2017-2-16 08:40
I don't understand.  msinger wrote:

It will not be initiated if only the downlink (Wi-Fi) disconnects.

Confuses ? Who said confuses ?

I said it does not answer the LATER question initiated in the thread ... we have all answered the original starting question.

The thread went on to suggest that soon after loss of 2.4, that 5.8 would follow shortly after ... in fact I seem to recall WILLIAM M posted :
"Don't think so, every time my telemetry goes out the RC control signal is not far behind. I've also read many post/threads that state the very same. How else would the RC know to change it's large LED from green to red (connected vs not connected). That LED is the indicator of what the remote thinks the status of the control 5.8 GHz signal is. And since the 5.8 GHz signal is only a one way transmission, there is no other data inbound to the remote, except for the 2.4 GHz signal which is two way. You might think the video (FPV) and telemetry is out, but I bet it's just the video and the telemetry is still being feed to the remote"

Not quite same questions are they.

Let me post this then I will pick up the relevant change in question and edit here ...

Nigel

I think there is a language problem here.  

Certainly looks that way ... and ENGLISH IS MY FIRST AND NATIVE LANGUAGE ... I am English ... totally 100% ....

I think I have explained the subtle change in thread content and the change in question.

It started with whether update of Maps if video link drops and its a confused post saying from AC ... That got sorted early on ...

It then veered to the relation of 2.4 telemetry to 5.8 command signals ... and the debate of whether one affects other.

Nothing wrong with my English there ... unless its supposed to be written in corrupted Microsoft US rap style ?

Nigel