Kestrel question.- Correct altitude ?

Discussion in 'General Discussion' started by Down Under Hunter, Jun 30, 2008.

  1. Down Under Hunter

    Down Under Hunter Well-Known Member

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    I recently have been only using the BP , RH and temp for the NF exbal program. I also wish to enter alt but dont know how to set the right refence so I get the numbers I need. If I remember correctly it refences a BP figure.

    I use raw station pressure for my BP numbers. So I enter "0" in the refence screen currently and I'm told this is correct. Just want a accurate alt to enter in Exbal.

    Thanks once again fellas !

    DUH
     
  2. Eaglet

    Eaglet Well-Known Member

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    DUH, you might want to read these posts, starting on the third post down. Let me know what you think.
     

  3. Down Under Hunter

    Down Under Hunter Well-Known Member

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    Eaglet.

    Thanks for the tip.

    I agree with your theorys completely.

    When I saved sight in conditions I entered zero in the alt box. ( I will need to change that )

    I have unchecked the the top box in the sight in conds page. ( I think that is what I need to do )


    Now that I know I need the alt figure I will enter the raw stn pressure figure I had that day as the refence and enter in the alt box the number the kestrel gives me for alt.

    To get the correct alt figure on the kestrel it asks for a refence figure BP- alt, alt - BP I think.

    I still am confused a little. DO you mean that I get the raw stn BP, then go to the alt function and re enter the raw stn pressure figure as the refence ? This will then give me a alt figure based off the raw stn pressure ? Correct ?

    Many thanks

    DUH
     
  4. Eaglet

    Eaglet Well-Known Member

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    I hope this helps. If not, you can always PM or e-mail me.
     
  5. WWB

    WWB <b>SPONSOR</b>

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    When using the Kestrel Units to obtain the "Station" Barometric Pressure, the reference altitude must be set at 0 Feet. This will give you the "Station Pressure," which is what you want.

    To obtain altitude, you must set the BP reference to a known altitude for the current weather system. This is good for mountain climbers, as they may need to know what elevation they are at, although for Shooters utilizing Night Force Ballistic Targeting software, it is theoretically irrelevant.

    HOWEVER, you can use a combination of the altitude and the BP to obtain an even greater percentage (although very small) of accuracy. This is how it is done;

    1. Obtain an altitude reading from your GPS and enter it into the data entry point in your NF software.

    2. Make certain that you check the "Use Standard Pressure" pick-box

    3. Pick the "Calculate" button.

    4. Re-Run the calculation again, but first uncheck the "Use Standard Pressure" pick box and enter your current BP "Station Pressure."

    5. Pick the calculate button again.
     
  6. Down Under Hunter

    Down Under Hunter Well-Known Member

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    Thanks boys for your assistance.

    Thaks eaglet for your help mate. To be honest I am still confused though.

    Sitting at my PC now I can get a altitude and BP reading from our local airport. I know that the airport is 163 feet above sea level and the BP currently is 1028.1 hpa. CAn I use this data for input.

    It seems that with the kestrel that BP reference in the alt screen has a direct affect on the raw stn pressure on the BP screen.

    Thanks again all !

    DUH
     
  7. Eaglet

    Eaglet Well-Known Member

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    Don't give up, friend, just re-read what you have and it will became clear. Best I remember, it just did not come to me, I went back and forth untill it made sence. Don't give up! You can do it!
     
  8. jmason

    jmason Well-Known Member

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    Guys I know this is an old post but of all the old post I found this one is the most relevant.

    I want to save my"sight in conditions" so I don't have to keep re-zeroing. I understand how to do that. Where I'm lost is the altitude/pressure. I have a Kestrel.

    If I want to use the save sight in conditions option do I always have to use altitude and pressure for corrections on the field conditions screen? Can I just set 0' as the BP ref alt on my kestrel and use the station pressure with out the alt and leave "calculate standard pressure unchecked?
     
  9. MagMan

    MagMan Well-Known Member

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    That is how I do and it works just fine.

    I know we're talking Exbal but with LoadBase if you use station pressure there is no way you can use altitude at the same time. I figured I'd run them the same way, FWIW.
     
  10. jmason

    jmason Well-Known Member

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    Are you using Exbal too?

    If so then on both the sightin and field condition screens I can just set 0' as the BP ref alt on my kestrel and use the station pressure without the alt and leave "calculate standard pressure unchecked? Then I'm good to go and don't need the alt just my station pressure(with the alt referenced at 0)?
     
  11. MagMan

    MagMan Well-Known Member

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    I am using Exbal, just used LoadBase as a "for instance".

    My altitudes are set at 0 and I use the station pressure from my Kestrel. Some do it this way and some do not.
     
  12. Eaglet

    Eaglet Well-Known Member

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    Gents, I don't fully understand the confusion. Remember, "it's not how I do it" or "how you do it" the proper way to run the program but rather how it was intended buy the programmer.

    Please read from third post down and it's all explained here

    http://www.longrangehunting.com/for...ng-me-but-i-would-recommend-30622/index2.html

    If I am missing something I apologize. Please let me know.

    Once your zero conditions have been saved, as you change locations you change info in the field conditions and you ALWAYS enter the BP and the Elevation.

    You can always check it out your self, check the top left box on the "save sight in conditions" leave it checked and go back to your field screen enter different elevations from zero (0) to whatever and your answer will not change, they will be the same regardless of the elevation. This is because you're using the field condition as your zero in condition at the same tame. I feel I'm missing something and you guys will let me know...
     
  13. jmason

    jmason Well-Known Member

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    I don't know why But I was under the impression that I could use the station pressure (kestrel with 0' as the BP reference altitude) without the altitude and leave "calculate standard pressure unchecked. Are you saying this is not correct?

    If this is not correct than should I use a GPS for ALt and actual station pressure from the kestrel and allow exbal to correct the pressure for altitude?

    Or should I use a GPS for ALt and actual station pressure from the kestrel and leave "calculate standard pressure" unchecked?

    I'm sorry man I'm just a bit lost. The documentation that comes with the program is lacking a little and all my other ?s were answered by searching here. This one seems to have been an issue for a lot of people based on the search results. I am trying to ask the questions so a response of yes or no can be used so there is no Grey area for me to find in the responses.
     
  14. Eaglet

    Eaglet Well-Known Member

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    I really hope I'm understanding this right! You set the Elevation on the Kestrel at zero, so you read the station pressure off the Kestrel all the time, (If that's how the Kestrel give you the station pressure, that works for me) Now the reading from the Kestrel will always be station pressure and that's what you need regardless of where you are. You don't need to input the Elevation on the Kestrel! Cool! But you always enter the right Elevation and Station pressure on Exbal.
     
    Last edited: May 8, 2009