How to Calibrate an Altimeter

How to Calibrate an AltimeterWhile very handy, altimeters rely solely upon the changes in air pressure to provide altitude (lower air pressure = gain in altitude). Essentially, they are barometers that translate pressure changes into altitude gain or loss. This means that other changes in air pressure, namely storms and changing weather patterns, can directly negate the altimeter's accuracy. To have the most reliable altimeter readings, it's important to calibrate regularly.
 

Instructions

Difficulty: Easy

Step 1
Set the altitude. Before you even use your altimeter to get that first reading, it's important to set it to a known altitude. The specificities of your local and daily weather conditions can affect accuracy, so you need to set the altitude to a known quantity. Pick a location where you know the altitude, such as your hometown or the base of a mountain.
Step 2
Change the altitude on your altimeter. Changing the current altitude varies from altimeter to altimeter. Many modern altimeters are digital and are often combined with other devices like watches or GPS units. You'll need to select the altimeter function, click "Set" and follow instructions to set the altitude. Some altimeters are analog and require a manual setting of the reading hand to correctly align with the current altitude. This is often done with a control ring or bezel around the altimeter's face. Refer to the instructions of your specific altimeter for a more detailed description of setting the altitude.
Step 3
Calibrate your altimeter often. Though you may want to rely on your altimeter to provide you with the altitude, an altimeter's accuracy can diminish because of changing air pressures brought on by weather that you may or may not be aware of. To get the most accurate readings, you should set your altimeter often. When hiking or backpacking, look for landmarks that have a clearly designated altitude and set your altimeter as you come to these landmarks. Landmarks may be physically marked on trails (i.e., trailhead), or they may be found using a topographic map (i.e., peak, intersection, hut).
Step 4
Be aware of changing weather. Remember an altimeter is basically a barometer, so the changes in altitude that it displays are really changes in air pressure, which may or may not be related to your change in altitude. If there is a storm approaching, your altimeter may experience an increase in altitude even if you're not climbing. While this isn't helpful in tracking your altitude, it does make your altimeter a helpful tool in predicting weather.
Step 5
Test your altimeter. To keep an eye on the accuracy, check your altimeter when you stop for a break or are hiking a flat trail with no gain or loss. If it changes, you know that it needs to be recalibrated.
 

Tips & Warnings

 
Be sure to calibrate your altimeter when you travel to a new location. The altimeter needs to be set in the local weather conditions. Try to store your altimeter at the outside temperature, as temperature can also affect accuracy unless your altimeter is temperature compensated.
 
Be sure to calibrate your altimeter when you travel to a new location. The altimeter needs to be set in the local weather conditions.
 
Try to store your altimeter at the outside temperature, as temperature can also affect accuracy unless your altimeter is temperature compensated.

Article Written By Joe Fletcher

Joe Fletcher has been a writer since 2002, starting his career in politics and legislation. He has written travel and outdoor recreation articles for a variety of print and online publications, including "Rocky Mountain Magazine" and "Bomb Snow." He received a Bachelor of Arts in political science from Rutgers College.

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