Investigations of magnetic field disturbances at an air force base compass calibration hardstand

1990 ◽  
Author(s):  
Dwain K. Butler
Keyword(s):  
Magnetic Field ◽  
Air Force ◽  
Compass Calibration ◽  
Air Force Base

Investigations of magnetic field disturbances at an air force base compass calibration hardstand

Geophysics ◽  
1993 ◽  
Vol 58 (3) ◽  
pp. 434-440 ◽  
Author(s):  
Dwain K. Butler ◽  
Thomas B. Kean
Keyword(s):  
Magnetic Field ◽  
Air Force ◽  
Concrete Aggregate ◽  
Large Bulk ◽  
The Status ◽  
Bulk Magnetic Susceptibility ◽  
Compass Calibration ◽  
Air Force Base ◽  
The Magnetic Field

Investigations were conducted to determine the nature and cause of magnetic field disturbances at the calibration hardstand (compass rose) at an air force base. The disturbances have prevented the normal and routine use of the hardstand since its construction in the mid-1950s, with heightened concern over the problem every 10–12 years. The investigations included the characterization of the horizontal, vertical, and temporal variation of the total magnetic field strength both on and off the hardstand. On the hardstand, the field varies by as much as 1,000 nT over 10 m horizontally and by as much as 600 nT over 2.5 m vertically. Also, on the hardstand, the magnetic field varies extremely erratically with time by 50–60 nT over periods of a few seconds. Off the hardstand, the magnetic field is extremely stable, and varies by less than 10 nT over 10 m horizontally, 2.5 m vertically, and over periods of 10–15 min. The magnetic field “stabilizes” at distances less than 10 m horizontally from the edge of the hardstand. Both on and off the hardstand, the magnetic field variations are independent of the status (on or off) of a nearby instrument landing system (ILS) (approach radar). The results of the magnetic field characterization indicate that the cause of the problem is the hardstand itself. The hardstand concrete was found to have a large bulk magnetic susceptibility, and the concrete aggregate has a permanent magnetization sufficiently large to visibly deflect a compass needle; these factors, coupled with a correlation with the 11-year solar cycle, suffice to explain the magnetic “disturbances” at the hardstand.

Geology of northern Nellis Air Force Base bombing and gunnery range, Nye County, Nevada

10.3133/pp651 ◽  
1971 ◽  
Author(s):  
E.B. Ekren ◽  
R.E. Anderson ◽  
C.L. Rogers ◽  
D.C. Noble
Keyword(s):  
Air Force ◽  
Nye County ◽  
Air Force Base
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