A little experiment

Thread: A little experiment

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  1. #1
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    Aug 2008
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    A little experiment

    Yesterday I was on a train journey and I had decided too test the GW-9200 Riseman on altitude measurements. I started by setting the altitude on the watch to 5 meters since the starting station was located at 5.1 meters. I took measurements on every station the train stopped, in total 12 including first and last station. The length of the journey was 426.61 km (265.08 miles) and it took 5h18m38s. As you can see on the data, the journey went over some mountains and the readings of the watch was pretty accurate until the top of the mountains. The measurements after the mountains was about 40-60 meters too low and indicates a higher air pressure south of the mountain than north of the mountain (The journey was pretty much directly from north to south). I know the Riseman is not made for measuring altitude when travelling long distances because of air pressure changes, but it was fun to try.

    It is also cool when you are flying an airplane too see what the cabin pressure is and on what altitude that pressure is normal pressure. I have noticed that cabin pressure in a Boeing 737 equals an altitude of around 2000-2200 meters and on a 747 equals an altitude of around 1500-1700 meters.

    Every altitude is measured in meters above sea level. I tried to make a table using tabs, but that didn't work. Instead I had to use dashes to make it more readable.

    Station name - Official altitude - Watch altitude - Time
    Trondheim - 5.1 - 5 - 1527
    Heimdal - 143.5 - 145 - 1538
    Støren - 66.0 - 50 - 1608
    Berkåk - 450.6 - 445 - 1632
    Oppdal - 544.9 - 535 - 1656
    Hjerkinn - 1017.0 - 1025 - 1735
    Dombås - 659.3 - 625 - 1800
    Otta - 287.7 - 245 - 1832
    Vinstra - 241.4 - 195 - 1854
    Ringebu - 197.1 - 145 - 1918
    Lillehammer - 179.5 - 120 - 1947
    Hamar - 127.7 - 70 - 2045

    Maximum altitude: Official: 1024.4, watch 1025
    Minimum altitude: Official: 5.0, watch 5
    Total ascent: Watch: 1345
    Total descent: Watch: 1275

  2. #2
    Member WhtShadow's Avatar
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    Mar 2008
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    South Carolina
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    2,740

    Re: A little experiment

    Very nice. It looks like it did a pretty good job overall. After 5+ hour I am not surprised that is was off a bit, especially after that much distance.

    Thanks!

  3. #3
    Member
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    Jun 2006
    Location
    Malaysia
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    1,522

    Re: A little experiment

    Good to know that Riseman is accurate.

    Variation in air pressure does affect the altitude reading.However,it's good to see it's didn't differ much from the official value.

    Cheers,
    MountainMike

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