Dialing your kestrel in

[Shawn Carlock]

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Several questions come to me everyday about different items on the LRH how to video. One of the most common questions is, how do I get my Kestrel to read correct elevation". I have played with this and checked with GPS on several occasions. I prefer the GPS for true elevation but if you just have your Kestrel this is what I do:​

1. Go to the barometric pressure screen, set the reference altitude to zero if it is not already there, this will give you station pressure where you are.
2. I enter into my PPC all atomsphericial data.
3. Go to the PPC and check the "calc standard pressure" box. There are 2 pressure boxes, one is pressure at sea level and the other is pressure at altitude. Look at the pressure at altitude box and note the number. Compare this number to the station pressure on your Kestrel.
4. Let's say that the standard calculated pressure at altitude is 26.40 Now your station pressure from your Kestrel is 26.8 Subtract your standard calculated pressure from your station pressure. This gives you a difference of +.40.
5. On your Kestrel go to the elevation screen. Check what pressure the elevation is referenced (you may need to check the manual on how to do this as they are a little different). Most are set for a standard of 29.95. Add the difference of the station / standard calc pressure to 29.95. In our example this would be 30.35
6. Enter this number (30.35 is our example) as the referenced pressure for the elevation reading.
This will usually give you an elevation reading +/- 20 feet or so for elevation. In short here it is in formula form:
(Station pressure – calculated pressure) + 29.95 = The pressure to set the elevation reference to.
Hope this helps.

 

[davewilson]

i called Kestrel when i got mine and he said to go to an airport or any place where the altitude and BP were known. then enter each into the ref. entries and it would be "set". are you saying this method is not good enough?

 

[Shawn Carlock]

It can be. The problem I have seen is when changing elevation etc from the std airport setting. If the change is big I have seen some discrepencies in figures. It kind of reminds me of using a drop cam, if your close enough to your "set" conditions it is really good, if the conditions are alot different you need to direct dial so to speak. Honestly if your using station pressure correctly in the program the elevation is not as critical. The elevation still needs to be close but if it is off 100' it doesn't make much difference. SOme guys have wanted to know how to correct them in the field. This has been the most effective solution for me.