If you do not know where you are, a map on its own will not help you to find your way. But, a compass will point you in the right direction towards your lost path. Then, the map becomes useful again.


When performing field work for smart meter systems, we need to perform site surveys to gather information to inform the design and detailed engineering phases of the project.

Advanced Metering Infrastructure (AMI) networks are typically wireless networks. So, understanding the range and bearing between the gateway collectors and the endpoint meters is important to appreciate the subsequent performance of the links.

During the planning phase of the project we venture out to the field and assess a wide variety of parameters that can have impact on the network performance. Once gateway locations are established, we then need to do some RF (radio frequency) Propagation modelling to understand the potential radio link coverage. Issues such as terrain, trees and foliage, weather, parked vehicles, buildings and structures, and more can adversely affect coverage. So, while we are in the field, we use a variety of RF site tools to help provide insights into the situation and guide the final designs.

Some of these tools include:

A compass and an inclinometer are critical tools for site surveys. A trusted GPS is also important. Metercor uses all of these tools in its sight survey kits.

When using a compass, it is essential to understand magnetic declination.

Magnetic declination (sometimes called magnetic variation) is the angle between magnetic north and true north. Declination is positive when this angle is east of true north and negative when it is west. Magnetic declination changes over time, and with location. Declination value is needed to determine true north, because compasses point toward magnetic north. But engineering drawings, maps, and charts all use true north. So, it is critical to align the two parameters, or else major mistakes will result.

You can compute the true bearing from a magnetic bearing by adding the magnetic declination to the magnetic bearing. This works as long as you follow the convention that degrees west are negative (i.e. a magnetic declination of 10-degrees west is -10 and bearing of 45-degrees west is -45).

In Canada, since the country is so big, we experience a wide range of magnetic variation based upon your location. Therefore, you cannot forget about this important compass error. Many a sailors have lost their way and crashed upon the rocks. Make sure that you do not join this group of compass users.

Here are a few compass deviations for Canadian cities based upon the local airport references taken in 2018. The compass error can move up to 0.5 of a degree annually and swings to and from over the decades. So, whenever you use a compass, you must investigate the most recent deviation errors and apply them to your work.

I always use this mnemonic as a mental reminder – West is Best, East is Least. Meaning add the the current local deviation when you are west of the magnetic fields and subtract it when you are east of the zero point for the magnetic fields.