Antenna Orientation - Cisco BWX 8305 Installation And Commissioning Manual

Chapter 6 Installation

6.3.7 Antenna Orientation

The magnetic declination, which is the angular difference between observed magnetic north on a
compass and geographic (or "true") north, shifts from year to year. Panel antennas must be oriented
appropriately as required by the RF plan.
Adjustments that will need to be made are based on the Magnetic Declination Chart
provides values to correct the compass reading and determine the true geographic East. Always check
for the latest chart information, which may be found at the following web address:
www.thecompassstore.com/decvar.html.
Since this is not the year 2000 any more, you will want to check this reference chart to learn how your
magnetic declination may have shifted since then. Notice that the map measures annual shifts in minutes.
Since it takes 60 minutes to equal 1 degree, if you notice that your location has a declination shift of 5
minutes per year, this means it will be another 12 years before your declination adjustment changes by
one whole degree.
Figure 6-16
It is better to convert the "true" azimuth (which way the antenna should point in the horizontal plane) as
Note
required by the RF Plan to the magnetic value that will be read on the compass before sending the
installer to the field. This way the installer will go by the reading on the compass, not having to worry
about magnetic declination corrections.
OL-16336-02
Magnetic Declination Chart – Example
World Magnetic Declination Chart - Year 2000 World Magnetic Declination Chart - Year 2000
Use a compass to determine the magnetic East
Use a Magnetic Declination chart to correct the compass reading
and determine the true geographic East
BWX 8305 Basestation Antenna Installation
BWX 2305 Basestation Installation and Commissioning Guide
(Figure 6-16), which
Unit:Degrees Unit:Degrees
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