Kestrel help

[tomapleleafss]

I recently purchased my first Kestrel (used). It is the 4500NV, non-ballistic model. I am confused in regards to setting up the pressure and altitude. I have read you want station pressure as opposed to barometric pressure. I thought I had it but then when I took it out my density altitude was in the negatives (-300ish). I then compared with a internet density calculator with using the daily values from the government weather website (station is located about 100 kms away) and I was getting around 500 m. Can someone point me the right direction. Thanks.

 

[rugbydave]

It's perfectly possible to get a negative DA (especially when the temps are low and you aren't at altitude). I wouldn't rely on weather information from 100kms away.

 

[tomapleleafss]

It's perfectly possible to get a negative DA (especially when the temps are low and you aren't at altitude). I wouldn't rely on weather information from 100kms away.

But can the DA change almost a 1000 meters in a single day, from a location 100 km away. The weather station is 90 meters in elevation higher than where I was. Data for the area was 500 m (elevation), +8C, dew point -2C, and my pressure 28.1 inHg. The local weather station was saying pressure was around 29.8 inHg. But this is where I get confused. Is the weather station saying baro or station pressure? What about the Kestrel? Maybe this where I am getting confused. Am I comparing two numbers with two different sets of data? I did try to set up my Kestrel per Kestrel video on YouTube but it just doesn't seem right.

 

[kthomas]

DA can change a lot in a day. I've seen DA change by over 2000 ft in a matter of a couple of hours in Oklahoma and Texas.

I agree with what Rugbydave is saying, don't rely on information from a weather station that isn't at your exact location. Weather and atmospherica can be surprisingly different from small distances away.

 

[Tokay444]

Trust the Kestrel for instant DA.
There's no telling where the nearest .gov weather station is or how old the data is.
As a shooter, you also want your baro and station pressure to be the same, so that you're using actual BP in your calcs. Not corrected values.

 

[rugbydave]

But can the DA change almost a 1000 meters in a single day, from a location 100 km away. The weather station is 90 meters in elevation higher than where I was. Data for the area was 500 m (elevation), +8C, dew point -2C, and my pressure 28.1 inHg. The local weather station was saying pressure was around 29.8 inHg. But this is where I get confused. Is the weather station saying baro or station pressure? What about the Kestrel? Maybe this where I am getting confused. Am I comparing two numbers with two different sets of data? I did try to set up my Kestrel per Kestrel video on YouTube but it just doesn't seem right.

Generally the weather station gives you barometric pressure. Trust the Kestrel for your atmospherics.

 

[tomapleleafss]

I got it figured out. I had a ref altitude setup for my barometer. With it setup like this it was reading barometric pressure as opposed to station pressure. I was able to correct it and check it against a nearly new 5400. These read both barometric pressure and station pressure.