Correct Altitude is entered.
I'm getting an average error of 3.5 millibars.
My altitude is pretty close to the local airport, and I used a fairly calm
day to adjust my barometer to match that. Our altitude is also relatively
close, i.e. the airport is 4403ft and I'm at 4410. Althought that 4410
could be off, I had used that for my altitude for years.
Took another reading via gps today and have adjusted that to 4293, which
seems like it could be a significant differences.
Thanks so much for your help in getting me to understand it. I've managed
to learn to ignore the wind errors, as I live on a hillside and don't see
anyway my wind data will ever match. if I need to do that for barometer,
I'll work on it. lol.
Would just like to figure out what I'm doing wrong.
1. That you have a Vantage console;
Vantage Vue Console
2. That you are using regular LOOP packets, not the newer LOOP2 packets;
loop_request = 1
3. That you are using hardware record generation.
prefer_hardware
>From the wee_device command.
BAROMETER CALIBRATION DATA:
Current barometer reading: 30.222 inHg
Altitude: 4293 feet
Dew point: 24 F
Virtual temperature: 32 F
Humidity correction factor: 1.1
Correction ratio: 1.175
Correction constant: +0.000 inHg
Gain: 0.000
Offset: -16.000
On Sunday, January 10, 2021 at 5:01:53 PM UTC-8 [email protected] wrote:
> I'm assuming:
>
> 1. That you have a Vantage console;
> 2. That you are using regular LOOP packets, not the newer LOOP2 packets;
> 3. That you are using hardware record generation.
>
> If all this is true, then what's happening is that WeeWX is downloading
> altitude and temperature corrected barometric data (what pilots call QFF)
> from the console. However, CWOP wants pressure corrected only for altitude
> (not temperature; pilots call this QNH). So, WeeWX uses an algorithm to
> calculate that. This is then what is uploaded.
>
> First thing is to make sure you have the correct altitude entered in your
> console. You will also want to know whether the console is applying any
> barometric corrections. Both can be checked using the utility wee_device,
> with the --info <http://www.weewx.com/docs/hardware.htm#vantage_info>
> command.
>
> *wee_device --info*
>
> This will tell you what altitude your console thinks it's at, as well as
> any barometric calibration data.
>
> -tk
>
>
>
> On Sun, Jan 10, 2021 at 4:24 PM Brent Dowell <[email protected]> wrote:
>
>> I've been chasing my tail a bit trying to get my data that I upload to
>> CWOP to pass the madis checks, which, from what I've read is a bit
>> problematic.
>>
>> My question though is what should I have my console set as far as
>> altitude and barometer reduction. Right now I have it set for my correct
>> altitude and am using the altimeter setting. My readings are consistently
>> 'low' compared to the madis QC Check.
>>
>> It looks like to me that the values being uploaded are in fact low (raw
>> aprs data) and do not match whats on my console. So it appears that weewx
>> must be doing some altimeter calculation on my data and is sending that on
>> to cwop? I'm wondering if I'm missing a setting somewhere in my weewx
>> config to accout for that?
>>
>> Some of the research I've done on the issue talks about davis being a bit
>> of a pain because they out put the altimeter corrected data already and
>> that setting altitude to 0 and using the altimeter reduction fixes it?
>>
>> Sorry about dredging up an old issue, but I couldn't find much recent
>> information on this.
>>
>> Thanks in advance for any help.
>>
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>>
>
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