P4p compass error “Strong Magnetic Interference” issue

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Hi gang.
I posted this in the Help section but getting no responses.
Here’s the link Phantom 4 Pro v2 won’t calibrate- but P3p works fine
Phantom 4 Pro v2 won’t calibrate- but P3p works fine

I’d appreciate some input if anyone can help.
Short version is yesterday at a job my P4P v2 would not Startup up. Compass error. And no matter where I tried- even several blocks away in a park- same issue and a warning after failing to recalibrate- “ strong Magnetic Interference.
But my old P3P started up & locked gps immediately.
When I returned home, the P4P worked again fine.
How do I diagnose the issue and fix??
 

ianzone

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Hi gang.
I posted this in the Help section but getting no responses.
Here’s the link Phantom 4 Pro v2 won’t calibrate- but P3p works fine
Phantom 4 Pro v2 won’t calibrate- but P3p works fine

I’d appreciate some input if anyone can help.
Short version is yesterday at a job my P4P v2 would not Startup up. Compass error. And no matter where I tried- even several blocks away in a park- same issue and a warning after failing to recalibrate- “ strong Magnetic Interference.
But my old P3P started up & locked gps immediately.
When I returned home, the P4P worked again fine.
How do I diagnose the issue and fix??
Tryed a imu calibration,what's the sensors reading,,normal ,is this built in screen ? Try start without connecting to app ,if does arm and start reinstall the app,,if not I would start with imu then compass ,,any extras been added to drone,when doing compass calibration do very slow turns,
 
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I am not excluding your P4P was recently exposed to strong magnetic field such as speaker near by and compass in legs are « gaussed ». Just a guess as happening wathever location and tried recalibrating.
 
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I am not excluding your P4P was recently exposed to strong magnetic field such as speaker near by and compass in legs are « gaussed ». Just a guess as happening wathever location and tried recalibrating.
this.
 
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I am not excluding your P4P was recently exposed to strong magnetic field such as speaker near by and compass in legs are « gaussed ». Just a guess as happening wathever location and tried recalibrating.
If that was the case, why was it fine when I returned home?
And I checked it this morning, inside the house, and the compass and IMU were both in the Green (excellent) range. Again, totally normal.

And why did the P3P have no issues whatsoever? In fact it always has locked on the GPS way faster than the P4P.
 
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How do I diagnose the issue and fix??
The usual explanation for a persistent failure to calibrate is a disconnected compass - usually a broken wire or connection in the landing gear.
To confirm whether this is the cause, go to the Sensors section of the app settings and see what it's telling you about the compass.
 
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The usual explanation for a persistent failure to calibrate is a disconnected compass - usually a broken wire or connection in the landing gear.
To confirm whether this is the cause, go to the Sensors section of the app settings and see what it's telling you about the compass.
I did. It looks very different than in Go for the P3p, but the compass - both 1 and 2- both were green and very low numbers. Both in the “Excellent”
Range.
And I don’t have a Persistent failure to Calibrate. It happened yesterday while in Milwaukee.
But was fine two days previous, and also after I returned home.

And once last fall when shooting a property that had 2 real tall microwave towers.
But once I got 2-3 blocks away, was able to fly just fine.

This doesn’t seem like a broken or damaged compass wire.
Tomorrow I’ll do a screenshot of the sensors & post it.
 
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My experience with all my DJI drones (P3 4K, Mavic Air, P4 Adv) is that the warnings they throw up are real, not problems with the drone. These include excessive wind, strong signals, and magnetic interference. With the exception of wind aloft, measuring the others with external instruments does indeed confirm the presence of those interferences. It is a very risky move to view it as a problem with the drone. Your location is much more likely the problem, and you risk a drone crash by ignoring them. The laws of physics that govern these situations haven't changed in 100 years.
 
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My experience with all my DJI drones (P3 4K, Mavic Air, P4 Adv) is that the warnings they throw up are real, not problems with the drone. These include excessive wind, strong signals, and magnetic interference. With the exception of wind aloft, measuring the others with external instruments does indeed confirm the presence of those interferences. It is a very risky move to view it as a problem with the drone. Your location is much more likely the problem, and you risk a drone crash by ignoring them. The laws of physics that govern these situations haven't changed in 100 years.
Thanks- but wasn't assuming anything. I couldn't start or even calibrate the P4P, so it didn't get used.
The P3P however had no compass problems at all, and flew fine.
I think that if its not a Problem with my drone, then the P4P is more sensitive to the magnetic issues - or has a different system- for better or worse - than the P3P.

There obviously was something going on there (Milwaukee) as my same drone had no problems once I got back home. I just want to be sure that what I experienced isn't something getting out of whack that could get worse, or give me more issues on a job.

Have you noticed that the P4P takes longer to lock onto the Homepoint than the P3P? It's been that way for me since I got it. That's a little annoying - but the upside of the Occusync outweigh that little problem. As long as it lets me fly.....
 
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Yes, although I haven't used the P4 all that much yet, as the ground is still buried in snow. The temps just went above freezing this week.

Overall, from what have seen, the P4 software is a complete re-write from the P3, and somewhat different than the Mavic Air. The P4 and Mavic both throw warnings earlier by quite a bit than the p3 4K, which I view as a plus.
 
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ianzone

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Another thought just came to mind while reading (catching up),in app under warnings clear them all in case it's causing it ?? Just a thought wl ways cleared mine,when it was alive
Typical phantom ok one sec then it through a curve ball to wake us up
 
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How do you clear them? Where in the menu do I look for that option?
 
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Another thought just came to mind while reading (catching up),in app under warnings clear them all in case it's causing it ?? Just a thought wl ways cleared mine,when it was alive
Typical phantom ok one sec then it through a curve ball to wake us up
How do you clear them? Where in the menu do I look for that option?
 
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You don’t want to clear them. You want to change your location until they go away. They shouldn’t be viewed as a drone problem but an external environment problem that has the potential to end in a drone crash.
 
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You don’t want to clear them. You want to change your location until they go away. They shouldn’t be viewed as a drone problem but an external environment problem that has the potential to end in a drone crash.
Appreciate that.
My question is, how to I analyze the issue at hand to be sure it was environment rather than my P4p?
Only because the P3p locked in immediately and flew without issue.

Here’s the approx address of my target for the job. If anyone can see or find an obvious source of Magnetic Interference, I’d be interested to know.
Seems like a regular residential neighborhood in a mid sized city.
No obvious industry or even radio towers that I could see.
And I went 2 blocks north and 1 East to a park to test again. Same result P4p- no go, P3p- immediate lock.
 

ianzone

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Here’s the approx address of my target for the job. If anyone can see or find an obvious source of Magnetic Interference, I’d be interested to know.
Seems like a regular residential neighborhood in a mid sized city.
No obvious industry or even radio towers that I could see.
Magnetic interference doesn't come from radio towers.
It's going to be something within a few feet of the drone.
Something steel or live electrical cables.
The most common cause is launching from steel or reinforced concrete surfaces.

You said the drone works at home which suggests that the location is the problem and not the drone.
But you said that it doesn't work when you move two blocks away,?
Do you have an intermittent compass connection issue?
 
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Magnetic interference doesn't come from radio towers.
It's going to be something within a few feet of the drone.
Something steel or live electrical cables.
The most common cause is launching from steel or reinforced concrete surfaces.

You said the drone works at home which suggests that the location is the problem and not the drone.
But you said that it doesn't work when you move two blocks away,?
Do you have an intermittent compass connection issue?
Sorry if I wasn’t clear. The P4 P works almost all the time, almost anywhere.
I’ve only had this compass error thing 2 times.
Once - last November when trying to shoot a bare property with 2 tall towers on it- and when I got 1/4 mile away, was able to fly and even get relatively close th the property.

The 2nd Time was on Monday, in Milwaukee.
And I could not get a compass lock anywhere around the site, nor even going 2-1/2 blocks away in a park. Nor would it let me recalibrate the compass.
But the P3p did. Without issue.

But once I got home, was able to launch the P4 just fine.
It’s been raining last 2 days somdidnt get a chance to go out- but pretty sure it will
Fly anywhere in the area.
 

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Sorry if I wasn’t clear. The P4 P works almost all the time, almost anywhere.
I’ve only had this compass error thing 2 times.
It's rather difficult to make sense of the issue as described.
Something's missing.

It takes a lot of steel to set the compass off - or a small amount very close to the compass.
A bolt a couple of inches away can set it off or a large steel roof at 6 feet.
But if you are more than 10-20 feet away, no amount of steel will affect the compass.
Here's a 1000 ft steel object that weighs >100000 tons.
At this distance the compass doesn't even notice it.


Here's what the app shows when you put the Phantom on a car's steel roof:

The warning says: Magnetic field interference Move the aircraft or calibrate compass
(calibrate compass is obviously not going to fix the problem)

If your drone is working properly away from the site, that's an indication that the Phantom and its compass is OK.
What screen message are you seeing?
 

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