Barometer Sensitivity and Accuracy

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1

Seems that my barometer reading is reading very high and very low from the median. I have had readings of 30.6 and 29.2 as extreams.

I am located at 8700’ and saw a slope adjustment in setup for the barometer. Is that something that I could use to adjust the extreames using a local airport reading as a reference?

I thought it was a problem with the Davis and sent it back but the new one does it too.

greg

2

the alititude might be playing a part
i.e you might be better off using the use qfe baro, in the units setup (and set your altitude their as well)

3

OK I will try that…what is qfe? and where can I go to understand this phenomenon better??

greg

4

OK…clicked the QFE and the reading wnet to 67.04 in…and there was no doing any correction in the offset area…

So that doesn’t seem to make things better.

greg

5
what is qfe? greg

QFE = Field Elevation (reported by airports)

QNH = Nil Height (ie. sea level)

6

There was a similar thread on weathermatrix a while ago, also concerning a Davis at altitude
http://www.weathermatrix.net/bbs/vantageproboard/2003/1/messages/886.html

7

hi greg
before ticking the qfe, set the altittude in feed, and also remove the baro offset you have set in the barometer/offset/rainfall setup
as a test
which davis station do you have>?
as i had been told the VP has built in temperature /altitute (QFE) compensation

8

OK here is what I tried.

My altitude is 8720 MSL. I put in 0000 into the Davis VP and tried to set the BP to QFE in WD as an offsetand it went out of range…30.94 and could not adjust with offset.

If I put 1000 MSL into the setup of VP I could then adjust the offset of WD to 7.3 inches and it is now set to the BP at a local airport…I will track it for a while and let you know.

About 8 months ago I reported this to Davis. They sent me a new console and it did the same thing. So this is news to me that their algorythm is the problem…they did not tell me about that. So I guess I am a bit miffed but will try to continue to live with it.

monitor if you like at www.antiquesforanimals.com/ConiferColorado.htm

9

That seems to have done the trick. It has been running for a week and I have no spikes and it tracks well with an airport reading.

greg :lol:

10

so, a simple offset in WD is doing a good job, and that QFE adjusted barometer is not needed.
well, thats good
becuase i have had huge arguments with Ed and Tim West of ambient in the past about this, they said that wd would be inaccurate if it didnt use QFE…

11
so, a simple offset in WD is doing a good job, and that QFE adjusted barometer is not needed. well, thats good becuase i have had huge arguments with Ed and Tim West of ambient in the past about this, they said that wd would be inaccurate if it didnt use QFE...
I have never used QFE. It may depend on the weather station. I have always been satisfied using the WD offset to adjust my barometer reading (OS WMR-968). So, a simple offset in WD is doing a good job for me.