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Ideal compass value

Discussion in 'Pro/Adv Discussion' started by Aquarius4058, Feb 24, 2016.

  1. Aquarius4058

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    I just like to have a good understanding on safe compass value on P3P. I've seen somewhere before that the
    ideal compass value is between 1400 to 1600. What happens if the reading is below 1400? like 1350. sometimes I see a higher value of 1600 to even 1800. I would really appreciate any inputs. Thank you.
     
  2. John Locke

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    Sometimes all you have to do is move the craft to another location 30' away and it will come in range 1400 to 1600, such as moving off of concrete with rebar beneath. Sometimes all you have to do is move yourself away from the craft. But if those don't work you should re-calibrate in an open field. I personally don't like calibrating in new areas because you never know what's below you or around you that may cause a magnetic anomaly. If there's a magnetic anomaly where you're calibrating and you perform a successful calibration, you may have just acquired a really good BAD calibration, and don't know it. I like calibrating in places that I've calibrated before successfully and has worked for month with no problems. But, if you're out and about an need to calibrate, get out in a field somewhere as best possible. Never do it over concrete, which can have rebar in it. Try to avoid asphalt, but I've done it many times without an issue, just hold the bird way up over your head as high as possible, that's what I do. Some folks say the asphalt can be a problem for some reason, not sure why.

    Always look at the mod value after a calibration when you're 100' up to make sure things look right.
     
  3. Aquarius4058

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    Thanks for your input. but this doesn't really answer my question. I am pretty much aware on what you've said. I just like to know what is the ideal compass value. let's say, 1350 value is that good? is it better that 1400-1600? what it means when reading is higher than 1600? is it still safe to fly? or the craft will be more prone to compass error? Thank you.
     
  4. Trackman1

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    Besides the the mod value, I look at the map. I place the drone on the ground facing either towards or away from the road or parallel to the road. Then before starting engines I look at the map to make sure the orientation of the drone is the same as the arrow head on the map. In most cases there is likely a road near by to get squared up with.
     
    With The Birds likes this.
  5. Aquarius4058

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    What are you talking about Trackman1?
     
  6. John Locke

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    I assumed you knew that 1400-1600 was ideal, since you stated you had read it already. IMHO, 1400-1600 is ideal. I don't fly with mod values outside this range because from experience I know something isn't right. I do what I stated to get something in that range. With the steps stated, 90% of the time my mod value usually comes in at 1450 to 1500 without doing anything special, so I fly.
     
    #6 John Locke, Feb 24, 2016
    Last edited: Feb 24, 2016
  7. sudarwika_bali

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    nice tips for me. thanks sir..!


    Sent from my iPhone using PhantomPilots mobile app
     
  8. J&L

    J&L

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    I still can't find these GPS numbers. I see how many satellites on the left side of the go app but I can't seem to find what y'all are talking about.
     
  9. Djw93

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    I can not find the compass numbers either. Where are they in the go app?


    Sent from my iPhone using PhantomPilots mobile app
     
  10. msinger

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    You can find them in "MC Settings" --> "Sensors".
     
  11. sudarwika_bali

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    may i help you, open dji go apps, tap on top left on the screen called flight mode icon (quadcopter logo and P-GPS)
    than tap "sensor"
    you can see your sensor value: Gyroscope, Acceleration and compass value.


    Sent from my iPhone using PhantomPilots mobile app
     
  12. Trackman1

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    I place the drone on the ground so that it is square with the road going past my house. Then I check mod values (ok)
    Then I look at the google earth map to see if the arrow head is square with the road as it should be if compass is correct.
    Sorry for poor explanation. I made a video.
     
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  13. Aquarius4058

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    Got your point Trackman1.. Thanks mate.
     
  14. Aquarius4058

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    Thank you all for your inputs. I will do my research and post it here once I've a good answer on my question. I am still not sure when you get a number outside the so called ideal (1400-1600). lower value than 1400 is that mean lower magnetic interference? and higher than 1600 indicates higher magnetic anomaly? Don't get me wrong, I don't fly outside the 1400-1600 value also. I just like to understand the meaning of these values. Thank you all!!. peace to all and have a safe flying...
     
  15. Air Ontario

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    My understanding is that the number will/should swing a,bove and below any value between 1400 and 1600 and then settle on a number between the two, like 1500, for example.

    They look at any magnetic field present, the earth's( the correct one) or car, rebar, etc. If they are outside those numbers(1400-1500) constantly, I would compass calibrate in a know stable area and retry. If you go back to the same spot to launch and continue to get bad compass swing values AFTER calibrating, I would move from there, you have magnectic issues at that locale.
     
  16. Aquarius4058

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    Well, I have a chat with DJI's Tech support and this is what I got from them. She stated that the ideal values of the compass should be between 1000-2000. I asked an official documentation for it but she said there is no official documentation, those values is what they use for reference. I will stay with the 1400-1600 figures to keep it safe until I can find a good answer and understanding how this values affects the compass.
     
  17. Oso

    Oso

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    This great post from @BudWalker doesnt specifically answer your question about what happens if you're above or below the target, but it may help you figure out what you want to know.

    Compass Calibration: What is measured?
     
  18. Aquarius4058

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    Here's an article that I found it very useful although still didn't answer my question.. Thanks guys... happy and safe flying to everyone...
     

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