Which way is North?
If you are like most of us, you’d assume that it is the same direction year to year, and matches what is on the map.
Not so – I checked my home QTH at this NOAA Website – LINK URL http://www.ngdc.noaa.gov/geomagmodels/struts/calcDeclination
I found that it has moved from an East to a West declination in my lifetime:
Important for survey work, it is useful to know for DX bearings in cases of wide declination – example take Bisbee, AZ the offset is roughly 10 degrees.
Interesting tool and useful if you are putting up a tower or configuring a multi-antenna array.