Quick compass question – when calibrating.

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first time in a long time had error message re-calibrate compass. I was about 100 miles from where I normally fly and I have rarely ever recalibrated. So I did the calibration everything went green/OK. Calibrated in a field with no interference possible. Then went over by a lake, again no interference. As soon as I got over the water got the error re-calibrate and went ATI mode. Windy but able to control it back. Did a couple more flights and never had another error, but wondering if I need to re-calibrate when I come back to my old location. And one other question-I read that you should not have a cell phone nearby, however my iPhone is what is running the app. Hmm. Thanks.
 
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Meta4

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first time in a long time had error message re-calibrate compass. I was about 100 miles from where I normally fly and I have rarely ever recalibrated. So I did the calibration everything went green/OK. Calibrated in a field with no interference possible. Then went over by a lake, again no interference. As soon as I got over the water got the error re-calibrate and went ATI mode. Windy but able to control it back. Did a couple more flights and never had another error, but wondering if I need to re-calibrate when I come back to my old location.
Compass calibration has nothing to do with distance from anywhere.
You won't need to recalibrate after going anywhere and it's unlikely that you needed to recalibrate it at all in the first place.
DJI's wording of the warning message is confusing.
It says Magnetic Interference - Move aircraft or calibrate compass.
The compass is warning that it's detected magnetic interference where you have placed the drone - recalibrating won't fix that but moving away from the problem will.
It might be that your flight incident was due to launching from the spit the compass was warning you of.
And one other question-I read that you should not have a cell phone nearby, however my iPhone is what is running the app. Hmm. Thanks.
Lots of things you read aren't true.
Everyone flies with a phone or tablet.
 
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Personally ...

I would get to a clear area that is clean of interference and just calibrate and then leave it alone. What you may have done is calibrate in a field that might have affected it ... then flying later you get an error.
Just because its a farm or clear field does not automatically mean its free of interference. You have no idea if there are electrical cables / piping / all sorts of stuff under your feet.

If you want to see how bad a field can be ... take an orienteering compass and walk across an area in a straight line - line up two objects and keep in line to make sure you walk straight - and watch the needle ... it may surprise you.

As regards the phone / tablet ... all you have to do is put the controller and the phone / tablet down a few feet away from the AC when you do the calibration .... there's no need to have it close to the AC.
 
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I am a little confused by your screen shot. You are getting 2 kinds of errors. 1 is the compas error which has been correctly analysed. You have 2 more that relate to strong interference that are usually caused by nearby strong WiFi sources. These have nothing to do with the compass. They are potential causes for the control and video downlink to fail.
 
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Question : What model do you have ? P3, P4, Mavic ????

VERY nice video ...
 
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The reason to Calibrate the Compass is to make sure it's flight path will be correct, although a good GPS signal will cause it's navigation to correct it's course left or right in spite of a Compass reading slightly incorrectly.

The Compass' positioning is based on Magnetic North, which varies (Declination angle) from True north as seen on the illustration here. If you were to calibrate the Compass in New Hampshire and move to Oregon your Drone's compass would be off by 30'. But if you were only a few hundred miles from where it was last Calibrated you would be fine.
 

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RodPad

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The reason to Calibrate the Compass is to make sure it's flight path will be correct, although a good GPS signal will cause it's navigation to correct it's course left or right in spite of a Compass reading slightly incorrectly.

The Compass' positioning is based on Magnetic North, which varies (Declination angle) from True north as seen on the illustration here. If you were to calibrate the Compass in New Hampshire and move to Oregon your Drone's compass would be off by 30'. But if you were only a few hundred miles from where it was last Calibrated you would be fine.
I used to think the same, but what I have learned from this forum, and reading many @Meta4 posts on compass issues.

The calibration is not the location, it is a calibration for the Phantoms structure.

Litchi Mission Switch to ATTI mode mid mission - P3P

The Beginning: Litchi Mission Switch to ATTI mode mid mission - P3P
Rod
 
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Compass calibration has nothing to do with distance from anywhere.
You won't need to recalibrate after going anywhere and it's unlikely that you needed to recalibrate it at all in the first place.
DJI's wording of the warning message is confusing.
It says Magnetic Interference - Move aircraft or calibrate compass.
The compass is warning that it's detected magnetic interference where you have placed the drone - recalibrating won't fix that but moving away from the problem will.
It might be that your flight incident was due to launching from the spit the compass was warning you of.

Lots of things you read aren't true.
Everyone flies with a phone or tablet.

Thanks, just reaffirmed my thinking on the issue. I was flying my older P3S, so typical to have interference and connection issues. Still in the novice level, even after a couple years, but want to get more proficient before investing in a P4 or go Mavick. You may have noticed from the Geneva Lake video I was cautious and did not fly far over the water with the wind if I had to manually recover. :) I have used a windsurfer, but with little improvement, and I'm not that savvy to install a signal booster myself. Cheers
 
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The calibration is not the location, it is a calibration for the Phantoms structure.

If that was the only item of regard for compass calibration - then you would not get errors due poor locations. It is true that the structure is allowed for in the calibration but external magnetics still plays a part.

Its a never ending argumentative discussion .....
 
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Question : What model do you have ? P3, P4, Mavic ????

VERY nice video ...
As I replied to Meta4, I was flying my old P3S, so interference and connectivity are always an issue. A windsurfer only improves signal slightly. Time to move on to a P4. Cheers
 

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@solentlife
"Its a never ending argumentative discussion ....." ;)


Rod
 
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About cell phone interference it is true. Usually I got messages about radio frequency interference when I had my cell phone near the RC or AC. As I have P4P+ I could easily turn the phone off but more practical is to turn it to Airplane mode. It would do no interference any more so you can run your GO or Litchi app. on it with no issues.
As I had often forgotten to do that before take up I wrote with big letters on my inner side of the box cover 'Switch the phone to aircraft mode' and doing so I have got no messages since then.
But this has nothing to do with the compass interference. The only effective cure for that is changing the take off position!
 
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About cell phone interference it is true. Usually I got messages about radio frequency interference when I had my cell phone near the RC or AC. As I have P4P+ I could easily turn the phone off but more practical is to turn it to Airplane mode. It would do no interference any more so you can run your GO or Litchi app. on it with no issues.
As I had often forgotten to do that before take up I wrote with big letters on my inner side of the box cover 'Switch the phone to aircraft mode' and doing so I have got no messages since then.
But this has nothing to do with the compass interference. The only effective cure for that is changing the take off position!
Good tips, I used to remember to go airplane and close all other apps and it does help. Was flying my older P3S,so regular connection and interference on that wifi link. P4 in the future....maybe a Mavick (but not the mini). :)
 
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About a year ago I had a similar incident in a port city in France. Otherwise my drone always flies reasonably stable, but on this particular day I received similar notifications and switched the drone to ATI mode. The only thing I could think of afterwards was that the drone is sensitive to the use of the VHF band.

@HIWEEL Very nice video.
 
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Meta4

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The Compass' positioning is based on Magnetic North, which varies (Declination angle) from True north as seen on the illustration here. If you were to calibrate the Compass in New Hampshire and move to Oregon your Drone's compass would be off by 30'. But if you were only a few hundred miles from where it was last Calibrated you would be fine.
Compass calibration has nothing to do with magnetic declination or where you are.
The only reason for compass calibration is to identify the magnetic fields which are part of the drone so they can be ignored.
Then the compass reading is accurate and not affected by any magnetic influences which are part of the drone.
The only time compass calibration is required is after rebuilding or modifying the drone.
 
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Compass and GPS errors seem to be confusing as to how they work together. My experience is that if the compass has errors due to being magnetized or for whatever reason, then the drone will revert to ATTI mode, which will of course cancel GPS NAV inputs, allowing the drone to drift. After traveling 1000 mile trips in a motorhome I have had good luck with degaussing the compass before recalibrating. Recalibrating alone has not always worked and the drone can and does revert to ATTI mode without warning. I can't say if it is the distance traveled or the motorhome metal around the drone which is causing the compass issues--maybe both. Mountain areas can also cause problems with compass and GPS.

Some people have posted that magnetic declination is not an issue and not a reason to re-calibrate. This may be correct.
 
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Same old arguments ....

My simple example I show to people when this compass matter comes up in conversation ....

I carry a hand compass in my bag ... age old habit - that's saved me a few times when lost in forest. Power up and then place it nearby .... so much for only affected by the drone itself !

Its the reason that bad location gives compass error - the magnetics affecting compass are anything magnetic around, under, over, near the compass - that includes pipework, keys, cables, anything in fact that carries or affects magnetic flux.
If that was not true - then a magnetic compass would not work.
Its also the reason its a bad idea to calibrate just because a warning comes up. That warning is most likely because of external magnetic influence throwing the compass of ... so the last thing you should do is calibrate there !
MOVE even just a few feet can make all the difference. But make sure you power down and up again to clear the old warning when you move.
 
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Same old arguments ....

My simple example I show to people when this compass matter comes up in conversation ....

I carry a hand compass in my bag ... age old habit - that's saved me a few times when lost in forest. Power up and then place it nearby .... so much for only affected by the drone itself !

Its the reason that bad location gives compass error - the magnetics affecting compass are anything magnetic around, under, over, near the compass - that includes pipework, keys, cables, anything in fact that carries or affects magnetic flux.
If that was not true - then a magnetic compass would not work.
Its also the reason its a bad idea to calibrate just because a warning comes up. That warning is most likely because of external magnetic influence throwing the compass of ... so the last thing you should do is calibrate there !
MOVE even just a few feet can make all the difference. But make sure you power down and up again to clear the old warning when you move.
Good point about powering down and up again. I did notice when I changed the battery and was in a little bit different area it never happened for three or four more flights or ever again for that matter.
 

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