Leica HDB barometric pressure or station?

[alsation]

I'm pretty new to this long range unknown distance game and bought a pair of leica geovid hb b brf's. They're really great glass w tons of features. Including barometric pressure reading. Reading on this site introduced me to the idea of barometric vs station pressure. Not entirely sure of the distinction between the two.

Does the Leica HD B give barometric or station pressure?

Thanks

 

[Saito]

I'm not sure what the "HD B" is, but I have a 1600B and it gives me barometric pressure. That's what really matters. IIRC, station pressure is corrected for altitude(and will fuck you up, ballistically speaking, if you live above sea level).

Say that you're at 5000' ASL and it tells you station pressure is 30.19. It can't be that high at that altitude and it's relating the pressure relative to Sea Level.

That's how I understand it. If I'm wrong, please correct me. There's some smart mo-fos in this site.

 

[anarchist]

I'm not sure what the "HD B" is, but I have a 1600B and it gives me barometric pressure. That's what really matters. IIRC, station pressure is corrected for altitude(and will fuck you up, ballistically speaking, if you live above sea level).

Say that you're at 5000' ASL and it tells you station pressure is 30.19. It can't be that high at that altitude and it's relating the pressure relative to Sea Level.

That's how I understand it. If I'm wrong, please correct me. There's some smart mo-fos in this site.

It's actually the other way around. Barometric pressure is station pressure corrected for altitude. That's why on the Kestrel, you need to set a reference altitude for the barometric pressure to be correct. If you zero out the reference altitude on the Kestrel, it will give you station pressure, or what the actual pressure is at your location independent of altitude. The most accurate method is to use station pressure. That will tell you how "thick" the air you're firing through is, which is all you care about. You should only use barometric pressure if you don't have any other choice. For example, if there's an airport nearby and you can get the barometric pressure and that's all you have, then use it, but you'll need to tell your ballistic software the altitude so that is can convert it back to station pressure.

 

[Saito]

It's actually the other way around. Barometric pressure is station pressure corrected for altitude. That's why on the Kestrel, you need to set a reference altitude for the barometric pressure to be correct. If you zero out the reference altitude on the Kestrel, it will give you station pressure, or what the actual pressure is at your location independent of altitude. The most accurate method is to use station pressure. That will tell you how "thick" the air you're firing through is, which is all you care about. You should only use barometric pressure if you don't have any other choice. For example, if there's an airport nearby and you can get the barometric pressure and that's all you have, then use it, but you'll need to tell your ballistic software the altitude so that is can convert it back to station pressure.

I switch my program over to "pressure is absolute" and it nixes out altitude as irrelevant. I understand how 'thick' the air is and that it's thinner at higher altitudes. At 5200' where I've done most of my shooting, my readings ranged from 24-25(inches of mercury I believe). I asked my old man what he thought it was and he told me, "probably 29.5 to 30". I told him I'd never seen it that high up where we were. His readings were from the airport and had been corrected for altitude. I may be incorrect in calling what I use "barometric". It works for me though. Just make sure you're not putting in altitude if your program is set to "absolute pressure" mode in your program.

 

[Papa Zero Three]

A picture is worth a thousand words. Use Station/Absolute pressure, do not input altitude as mentioned in the posts above unless you are using corrected pressure.

 

[scudzuki]

What is important is pressure, period.
It can be measured in PSI, millibars, or inches of HG, but it's the actual (station) pressure that's relevant, not the barometric presuure, which is station pressure adjusted for altitude.

Ballistics programs require barometric pressure and altitude to calculate the station pressure, which, again, is the relevant factor.

Being as the Leicas cannot know the altitude, they must report station pressure, and that's how I'll use my CRF 1600 B.

Joe

 

[scudzuki]

I'm not sure what the "HD B" is

HD B refers to Leica's GeoVid HD B, their latest generation combination binocular/rangefinder which, by all accounts, are SPECTACULAR.

Joe

 

[alsation]

Excellent! That's what I was trying to figure out. I used to think I knew a lot about shooting until I started getting interested in this type of shooting. Turns out now I've got to be a weatherman too!

Thanks for all the responses. Btw the geovid hd b are indeed a great pair of range finding binos.

 

[Pinecone]

It depends on the ballistic software.

JBM can use either station pressure or corrected sea level pressure. You just have to check the proper box.

You just have to KNOW which one you are using.

Virtually any hand held device will give station pressure, as it doesn't know the actual altitude.

 

[jasonk]

Excellent! That's what I was trying to figure out. I used to think I knew a lot about shooting until I started getting interested in this type of shooting. Turns out now I've got to be a weatherman too!

LOL, welcome to the sickness.