Thread: Kestrel / Barometric pressure / Ballistic Apps

Can someone please try explain in idiots terms what to do about the following:

I got myself a Kestrel 2500 from AllKestrel.com (awesome service, $ 220 NZ landed)

The Kestrel does "station" pressure.

So I know the altitude of my house (from topo maps), and have set the reference altitude to that. Then waited for the baro to stabilize and set the reference baro in the altitude screen, as per rtfm.

In shooter ballistic app, I leave "Pressure is absolute" ticked, correct ? It seems to grey out altitude, but you can still enter a value ???

And in JBM, I should leave the "Pressure is corrected" option unticked, right ?

I'm probably overcomplicating this, but let's say I am at 500m altitude, and a front is coming in, then the baro pressure will drop ? If I am at the same altitude and weather is good, baro pressure will be higher ? But the kestrel is always going to be working out it's idea of alttitude based on the baro pressure ? So on a stormy day even though I am still at 500m, the altitude might read different ?

So do I use the station pressure from the Kestrel, but enter the altitude from my topo map (so don't use the alt from the Kestrel) ?

Pressure "absolute" negates using alt.
Kestrel when calibrated will read pressure at your firing point. That's all you need to enter to shooter regarding pressure.
You need to however set your elevation when calibrating your kestrel to get the right pressure.
I calibrate it before every trip.
I confirm I have calibrated it right by enabling shooter when in coverage to access a weather station or check my pressure on the net.

In shooter I use Pressure is absolute and do not enter altitude. You only have to enter the altitude if you are using a corrected sea-level pressure.

Thanks guys

R93, I went thru the calibration steps as per manual, I'll be down at sea level tomorrow, so will re-do with 0m instead of relying on topo estimate.

Yup. I only live a few kms from the beach but I generally know my alt. It has not put me wrong using spot heights or the like.

Cool, am I on the right track about saying the Kestrel will then report different altitude depending on the current baro (if you are stationary at a specific alt during a change in weather) ?

Yup. Spot on.