Pressure

[cats_five]

OK, if I've read it right I need to set my weather station to send relative pressure, and I need to adjust that to take account of my altitude.

However, despite lots of Googling, I can't find the amount to adjust by! For flying we use 30' per mb, but I know that's rather approximate. What value should I used, please?

Ta

[steve]

It can only ever be an approximation; the rule of thumb I use is 1 mb per 8 metres. The best way to set a barometer is to use a nearby reference during a time of stable pressure.

[malc-c]

I think I too need some advise on this.

My WH1081 is showing 989.6 mb on its display, but the software is showing 1004.7 mb - can someone advise ?

Malcolm

[steve]

My WH1081 is showing 989.6 mb on its display, but the software is showing 1004.7 mb - can someone advise ?

You're looking at the 'absolute' pressure on the console - the actual pressure at your site. Cumulus is displaying the (more useful) pressure corrected to sea-level according to the 'offset' that you have put into the station. It looks like you have actually set the sea-level (relative) pressure, rather than it just being some random setting in the console, as 1004.7 looks about right for where you are.

[dane]

My WH1081 is showing 989.6 mb on its display, but the software is showing 1004.7 mb - can someone advise ?
Malcolm

On the console what does it say next to the "Pressure" text (above the reading)?
'abs'? or 'rel'?
You may switch between abs and rel by touching the pressure area, followed by touching the +button.

[malc-c]

Thanks guys,

The unit is showing "abs". What is the normal or "correct" setting that most people use. The local or adjusted for sea level value ?

Malc

[dane]

Mine is set to 'rel' so it matches what I see in Cumulus (not that I look at the console very often )