Look at the 2 lines. Both show 38° magnetic, but differ a lot. Why is this?
They are 5 degrees (True) off from one another. (45 and 50 degrees). Don’t know enough about it to know why Magnetic would show the same.
Maybe just not far of enough True gap to change Magnetic?
Not sure.
I wasn’t able to re-create:
I have quite old nav data here at work, so maybe that could be the cause? 2106 according to LNM.
Yes.
Hmmm… strange.
I don’t have much understanding of this stuff, but notice the VOR and Waypoint appear to have different values for magnetic declination.
The headings for a measurement from the Waypoint (pink) seem to match those from a random position nearby.
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Thats it …
Mixed up old and new MAGVAR data …
Ok, then I know why this is, probably: I need to reload the Littlenavmap database? I’ll do that right now.
The same discrepancy is shown in the Navaid panel for the airport. What’s the deal with magnetic declination vs calibrated declination?
No, this didn’t fix it.
I don’t think there’s anything to fix. It appears to be different ways of describing the declination - magnetic or calibrated.
Similar to how there are different ways of interpreting airspeed.
Shouldn’t I see the same thing in that case?
Why not ask @albar965 ? (Author)
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@CasualClick Thanks for letting me know.
I did not read the whole thread but …
VOR stations have a so-called calibrated declination which can differ from the real declination in the environment. The magnetic pole wanders which results in the real/environment declination changing slightly over time.
VORs needs to be calibrated according to changes in the environment declination which is an expensive thing and therefore not done often. BTG VORTAC was calibrated last in 1975, for example.
That is the reason for the differences.
LNM reads the environment declination from MSFS BGL files. For other simulators like X-Plane it uses the WMM (World Magnetic Model) to calculate the declination.
Now if you start a measurement line in LNM at a VOR (line is darkblue) it will use the calibrated declination. Otherwise its real/environment declination.
See also: 68. Magnetic Declination — Little Navmap User Manual
Hope this helps a bit.
Alex
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Thank you!
I guess I should read the manual. Finally.
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