Cell phones and compass issues.

[Byroman]

I work in the land survey industry. One of the tools we use on a daily basis to locate survey monuments is a magnetic location device. This tool is highly sensitive to a magnetic charge and, through visual and auditory means, tells you how close you are to charged objects (usually metallic).
One thing we know, is that while using this device, it is extremely hard to get good readings while there is as cell phone in your pocket or in your general vicinity. They throw a very strong magnetic field that makes our locator scream (literally... thats the best description of the sound).
With this in mind, I usually keep my Tx and phone about 10' or more away from the Vision during calibration and take-off. I am 1000% sure my cell phone can cause calibration/compass issues so I keep it at distance when I can.

Just food for thought (maybe this has already been discussed).

 

[dronesetc]

Interesting. One would think that after 1-3 feet of distance, the phone would no longer have an effect on the digital compass.

 

[gpauk]

If you think about it, most smartphones have a compass built in -- same sort of device as used in Phantoms.
Cell phones throw out an electromagnetic field for sure, but that shouldn't interfere with a compass.

The devices you use are either not very well designed from an EMI point of view, or, more likely, are much more sensitive and precision instruments and much more easily interfered with....

 

[MikeB]

I've seen advice that you should not carry any metallic or electronics objects when you calibrate the compass, due to this type of concern. But as I think about how they might interfere, I wonder if there's a simply workaround: rotate your whole body when calibrating, not just the Phantom. In principle, the compass calibration is looking for a peak and a minimum as it rotates. If the keys in your pocket are having an effect, they will end up shifting the peak and minimum slightly to one side. But if you are rotating your entire body with the Phantom at arms length, you are also rotating the effect of the keys in your pocket, so the peak and minimum aren't affected and the offset from true is reduced. Does this explanation make sense? Does anyone else see what I'm talking about?

 

[gunslinger]

I've seen advice that you should not carry any metallic or electronics objects when you calibrate the compass, due to this type of concern. But as I think about how they might interfere, I wonder if there's a simply workaround: rotate your whole body when calibrating, not just the Phantom. In principle, the compass calibration is looking for a peak and a minimum as it rotates. If the keys in your pocket are having an effect, they will end up shifting the peak and minimum slightly to one side. But if you are rotating your entire body with the Phantom at arms length, you are also rotating the effect of the keys in your pocket, so the peak and minimum aren't affected and the offset from true is reduced. Does this explanation make sense? Does anyone else see what I'm talking about?

I understand perfectly and I think you may have a point there. Although... I feel pretty silly just spinning the Phantom around in front of me. Holding it and turning circles will definitely cause the neighbors to call for the guys in white suits with butterfly nets...

 

[Pull_Up]

It's the way I calibrate when required now - holding it up at eye-level and revolving myself. Hadn't thought about negating the effect of keys and phones in my pocket, more about how much less I need to bend my knees and how much more visible the LEDs on the motor arms are doing it that way!

 

[Byroman]

Like I said...food for thought, thats all. I'm going to remove all possible sources of error to make my $1200 camera stay in the air.