Compass Calibration

RCRobman · Mar 13, 2015

I have been calibrating my compass before every flight so far and was wondering that since I fly in pretty much the same area - within a mile or two of each - do I need to keep calibrating? I have no problem with doing it but was wondering how far away from the last calibration point do you have to be before calibration is required?
Thanks for any help!

happydays · Mar 13, 2015

I haven't recalibrated ever.

Marlin009 · Mar 13, 2015

RCRobman said:
I have been calibrating my compass before every flight so far and was wondering that since I fly in pretty much the same area - within a mile or two of each - do I need to keep calibrating? I have no problem with doing it but was wondering how far away from the last calibration point do you have to be before calibration is required?
Thanks for any help!

The simple answer is no you don't.
The manual isn't clear on the distance. Shocking, I know.
I've read / heard 50 - 100 miles.

5.3 When Recalibration is required
（1） When Compass Data is abnormal, the LED flight indicator will blink alternating between red and yellow.
（2） Last compass calibration was performed at a completely different flying field/location.
（3） The mechanical structure of the aircraft has changed, i.e. changed mounting position of the compass.
（4） Evident drifting occurs in flight, i.e. the aircraft doesn’t fly in straight lines.

N017RW · Mar 13, 2015

#3 is a bit lacking in that if you add, remove, or relocate anything in or on the quad you will need to recal. While it may not alert you as in item #1, it can be observed by how it flies.

SteveMann · Mar 13, 2015

N017RW said:
#3 is a bit lacking in that if you add, remove, or relocate anything in or on the quad you will need to recal. While it may not alert you as in item #1, it can be observed by how it flies.

Also, don't wear a watch while calibrating the compass.

This is why you need to calibrate your compass when you change locations, and why there is no specific distance to trigger a recalibrate. You can see the magnetic anomaly map of North America here:
http://mrdata.usgs.gov/geophysics/map.html

Since it is a GIS based map, it will be very slow to render. Here's the magnetic picture of the contenintal US (you can zoom in to your location for detail, but rendering is slow.):

msinger · Mar 13, 2015

Here's a good thread on compass calibration:
viewtopic.php?f=4&t=32829

RCRobman · Mar 13, 2015

So essentially there is no need to re-calibrate unless your location has changed drastically - >100 miles!
Thanks to everyone that responded! Much appreciated!

jumanoc · Mar 13, 2015

RCRobman said:
So essentially there is no need to re-calibrate unless your location has changed drastically - >100 miles!
Thanks to everyone that responded! Much appreciated!

Also it is a MUST CALIBRATE if your Phantom went near to any magnetic source as woofers, speakers (in car or home), metal, magnets and electric sources, as motors, ovens, etc. I personally always calibrate 1st. flight in field or any different place I fly.
2 years without issues. :ugeek:

bbfpv · Mar 13, 2015

jumanoc said:
RCRobman said:

So essentially there is no need to re-calibrate unless your location has changed drastically - >100 miles!
Thanks to everyone that responded! Much appreciated!

Click to expand...

Also it is a MUST CALIBRATE if your Phantom went near to any magnetic source as woofers, speakers (in car or home), metal, magnets and electric sources, as motors, ovens, etc. I personally always calibrate 1st. flight in field or any different place I fly.
2 years without issues. :ugeek:

+1.

Great Pumpkin · Mar 13, 2015

Golly, how many times do we have to repeat this business about compass calibration? Just asking.

Thanks msinger for posting the thread once again and to ianwood for compiling it. My only quibble with it is that ianwood says beach sand contains iron which will throw your compass off if you take off from a beach. I tested this assertion and concluded that even the most iron-rich sands I could find have NO effect on the compass and flight performance*.

RCRobman: If you live in the western U.S. (Poleeze indicate in your profile where you are located), then the latitudinal (east-west) change in magnetic declination with distance is small (the lines of equal magnetic declination are far apart - see this chart http://maps.ngdc.noaa.gov/viewers/historical_declination/, but not so in the midwestern US, South America, and northern Canada where the lines are close together. There you would be wise to re-calibrate if you shift east-west position even 20 miles or so.

Steve Mann says:

Also, don't wear a watch while calibrating the compass.

My Swiss Army watch has NO effect on a compass. A mechanical pencil and a big belt buckle disturb a compass much more than a watch.

Incidentally, forum friends, this chart http://maps.ngdc.noaa.gov/viewers/historical_declination/ is really cool in the way that it shows how the magnetic declination changes over time. You'll see it isn't much from year to year, but check it out over centuries! We should all live so long to fly our Phantoms under such different conditions.

*I used a couple analog compasses to test some sand dunes with so much magnetite that several attempts have been made over the years to mine and extract the magnetite for profit. The sand is black with magnetite, but it had no effect on any of the compasses I tried, nor on my Phantom when I took off from the dunes.

N017RW · Mar 13, 2015

Great Pumpkin said:
Golly, how many times do we have to repeat this business about compass calibration? Just asking.

Thanks msinger for posting the thread once again and to ianwood for compiling it. My only quibble with it is that ianwood says beach sand contains iron which will throw your compass off if you take off from a beach. I tested this assertion and concluded that even the most iron-rich sands I could find have NO effect on the compass and flight performance*.

RCRobman: If you live in the western U.S. (Poleeze indicate in your profile where you are located), then the latitudinal (east-west) change in magnetic declination with distance is small (the lines of equal magnetic declination are far apart - see this chart http://maps.ngdc.noaa.gov/viewers/historical_declination/, but not so in the midwestern US, South America, and northern Canada where the lines are close together. There you would be wise to re-calibrate if you shift east-west position even 20 miles or so.

Steve Mann says:

Also, don't wear a watch while calibrating the compass.

Click to expand...

My Swiss Army watch has NO effect on a compass. A mechanical pencil and a big belt buckle disturb a compass much more than a watch.

Incidentally, forum friends, this chart http://maps.ngdc.noaa.gov/viewers/historical_declination/ is really cool in the way that it shows how the magnetic declination changes over time. You'll see it isn't much from year to year, but check it out over centuries! We should all live so long to fly our Phantoms under such different conditions.

*I used a couple analog compasses to test some sand dunes with so much magnetite that several attempts have been made over the years to mine and extract the magnetite for profit. The sand is black with magnetite, but it had no effect on any of the compasses I tried, nor on my Phantom when I took off from the dunes.