Multi Brand Alti / Baro comparison data...

Thread: Multi Brand Alti / Baro comparison data...

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  1. #1
    Member Jeff_C's Avatar
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    Multi Brand Alti / Baro comparison data...

    Well I started this in the beginning of October but had to travel for business so I didn't get a full month of data. But still, I did get a good bit of information.

    Each watch was calibrated for altitude before the test began. I was amazed with the accuracy of the Nike and the Core. Before you all get wadded up, you must understand that ALL of these ABC watches have issues with "barometric drift".

    A few more notes on the test... this test was done when my house had its windows open and the watches spent most of their time on my night stand next to an open window. The only exception being my Core... I wore that a LOT during the test... That means many trips to and from Atlanta (about an hour away) and many trips in and out of large office buildings etc... That makes its accuracy even more impressive in my opinion. Note that the Yachtsman does not have an altimeter, and the Observer never moved because the altimeter was locked

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  2. #2
    Member ColdHit's Avatar
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    Re: Multi Brand Alti / Baro comparison data...

    Could you send me this file to slowe55_pty (at) yahoo.com
    ...It does not do to dwell on dreams and forget to live!

  3. #3
    Member paduncan's Avatar
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    Re: Multi Brand Alti / Baro comparison data...

    Thanks Jeff...one thing I can see right away is that the Vector Baro wasn't calibrated accurately as your start value was different than the NOAA value (hence my other posts on this subject). I know you mentioned that you calibrated for altitude, but this doesn't make sure that the Vector (and other watches like it) sensor is calibrated properly.

    This is done using the SNR sub menu (hold Mode / Select down for 2 secs, tap select again, enter SNR mode, hold Select down for two more seconds, adjust baro pressure to that which is reported by NOAA). I think if this were done, the Vector (and other Suunto's which have the same basic engine) would do a lot better. Still, I like the fact that the Core allows you to get more granular with baro pressure readings (not just .05 increments).

    Quote Originally Posted by Jeff_C View Post
    Well I started this in the beginning of October but had to travel for business so I didn't get a full month of data. But still, I did get a good bit of information.

    Each watch was calibrated for altitude before the test began. I was amazed with the accuracy of the Nike and the Core. Before you all get wadded up, you must understand that ALL of these ABC watches have issues with "barometric drift".

    A few more notes on the test... this test was done when my house had its windows open and the watches spent most of their time on my night stand next to an open window. The only exception being my Core... I wore that a LOT during the test... That means many trips to and from Atlanta (about an hour away) and many trips in and out of large office buildings etc... That makes its accuracy even more impressive in my opinion. Note that the Yachtsman does not have an altimeter, and the Observer never moved because the altimeter was locked

    Last edited by paduncan; November 12th, 2007 at 18:39.

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  5. #4
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    Re: Multi Brand Alti / Baro comparison data...

    Interesting table, Jeff:

    FWIW, a quick look at your numbers shows this:

    Core Alti variance: 99 units
    Vector Alti variance: 370 unit
    ProTrek variance: 380 units

    Oddly, the Vector and ProTrek's Baro functions seem to track fairly closely to one-another.

    Thanks. That's useful info for people (like me) in the midst of an ABC watch decision-making process.

    Cheers from Edmonton, Alberta.

    Tim Yip

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    Re: Multi Brand Alti / Baro comparison data...

    Tim - then you have to calcluate the $$ per unit variation... LOL!

  7. #6
    Member ColdHit's Avatar
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    Re: Multi Brand Alti / Baro comparison data...

    Jeff, thanks for the file. I know what you are saying about moving or traveling with the watch. I am impressed with the Core in this regard as well.
    ...It does not do to dwell on dreams and forget to live!

  8. #7
    Member paduncan's Avatar
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    Re: Multi Brand Alti / Baro comparison data...

    Hi Jeff,

    So, the issue I am currently struggling with my new Core is in fact in your spreadsheet.

    You originally set the altitude at your known reference point, but your starting baro wasn't matching to the NOAA baro. (30.05 vs. 30.11)

    When the baro's did match at 30.03, your altitude is now 49 feet off from your starting altitude.

    Got any suggestions / comments on how to sync altitude up with pressure?

    Quote Originally Posted by Jeff_C View Post
    Well I started this in the beginning of October but had to travel for business so I didn't get a full month of data. But still, I did get a good bit of information.

    Each watch was calibrated for altitude before the test began. I was amazed with the accuracy of the Nike and the Core. Before you all get wadded up, you must understand that ALL of these ABC watches have issues with "barometric drift".

    A few more notes on the test... this test was done when my house had its windows open and the watches spent most of their time on my night stand next to an open window. The only exception being my Core... I wore that a LOT during the test... That means many trips to and from Atlanta (about an hour away) and many trips in and out of large office buildings etc... That makes its accuracy even more impressive in my opinion. Note that the Yachtsman does not have an altimeter, and the Observer never moved because the altimeter was locked


  9. #8
    Member Jeff_C's Avatar
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    Re: Multi Brand Alti / Baro comparison data...

    Sell the watch, get a portable weather station and a GPS? :)
    Suunto... Replacing Luck!



  10. #9
    Member paduncan's Avatar
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    Re: Multi Brand Alti / Baro comparison data...

    Quote Originally Posted by Jeff_C View Post
    Sell the watch, get a portable weather station and a GPS? :)
    LOL...maybe I am expecting too much?

    I am not familiar with your locale, so can you account for the differences in set altitude vs. the different baro pressure due to location (your baro is slightly different than wherever the NOAA locale was?)

    As I am "settling in" with my new Core, I see that it is working pretty well. I think it "could" be off by a millibar or so, but I suppose that will have to suffice.

  11. #10
    Member Jeff_C's Avatar
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    Re: Multi Brand Alti / Baro comparison data...

    Im going to be blunt... Your expecting to much. Off by a milibar is pretty spectacular actually! ALL ABC watches suffer from barometric drift. As you know, the barometer affects the altimeter and the barometer is affected by TONS of factors. Heck, going in and out of office buildings causes drastic pressure shifts, as does your car or airplanes. All of these factors can cause your pressure to skew slightly. Thus, your altimeter.

    So, its not so much a factor of precision, but mitigation of the very environmental issues that are playing with your watch at any given time.

    My NOAA station is about 7-10 miles away and is the local air field. I used it just as a reference. As someone who has sevearl of these ABC watches I can tell you that the Core results you see above are actually pretty tight. That watch was being worn 24/7 and NOT allowed to calibrate. None of the watches were re-calibrated at all during the test. All but the Core sat on a desk next to an open window.

    Now, here is the important thing. IN THE FIELD, the truly important thing is the trend. Thats EVERYTHING. It doesn't matter one bit (when in a real life field situation) whether the pressure is 30.07 or 30.10. The question is, what is the TREND doing.

    Its like the people that get wadded up because their thermometer is inaccurate when worn on the wrist. That has no practical bearing on REAL FIELD applications. So are you NOT going to climb one day because its cold? If course not. You WOULD want to know if the temp dropped radically VERY quickly... but your skin would tell you as much. Ive been caught in some crazy storms in Alaska. Ive been snowed into a snow cave for 4 days... And what good would any of this data be? None... because it is what it is...

    So how does the watch mitigate the effects of barometric drift? The Core has an auto function, or a "lock out" function... your choice... The Observer only has a "locking out" function... The Vector series is the most easily affected by barometric drift.

    The reality is that none of these watches are going to be 100% accurate 100% of the time. Its the nature of these kinds of watches.

    To me, the one flaw of the Core is that "pushing" a compass calibration is tricky. I agree with you there. I know its "supposed" to be self-calibrating but that doesnt do my heart good while in the field.. .then again, I rarely travel without a liquid compass.
    Suunto... Replacing Luck!



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