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RT System 2 v2.3 Deployment Guide
185
© 2010-2014 Wireless Seismic, Inc. All rights reserved.
F. Using a Compass
However, because of the dynamic nature of the Earth’s magnetic field, old maps are
inaccurate. To obtain the most recent declination values, enter your map location at the
following link:
http://www.ngdc.noaa.gov/geomag-web/#declination
To locate an object using a map and a compass:
1
Place the long edge of the compass baseplate on the map, connecting the desired start
and end points. For example, the start point could be where you are standing [A], and
the end point [B] is where you want to locate the backhaul mast. The Direction of Travel
arrow should point towards the end point (mast location).
2
While holding the compass on the map, turn the Degree Dial until the Meridian /
Orienting Lines are parallel with the Meridian lines on the map. This is the same as
turning the Degree Dial until the Orienting Arrow points to north on the map.
Figure F–2 Declination Indication on Map
NOTE
Placing magnetic objects near a compass can cause an incorrect reading
(deviation). Examples include:
• Objects that contain steel and iron such as pocket knives, belt buckles,
vehicles, railroad tracks, and ore deposits in the Earth
• Objects that use magnets such as stereo speakers
• Electrical current in cables and overhead lines
