[wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US

[Victor Engel]

In a discussion dated April 10,11 of this year, it was mentioned that
Weatherlink 5.7 resolved this problem. I looked but did not find a software
release notes page anywhere -- at least for notes older than the current
version.

Victor

On Sun, Jun 1, 2008 at 1:31 PM, Ted Lum <gladstonefamily.net at tedworld.com>
wrote:

>  I don't know. That thread is more than two years old and I don't know if
> it was ever resolved. I have not been able to find anything in the Davis
> release notes that say they made a change, but that does not mean they
> didn't. Since the pressure sensor is located in the console, NOT the
> station, if you see a variation with OAT then almost certainly its coming
> from a software calculation and not a temperature affect on the sensor its
> self. This is only circumstantial, but your observations seem to imply they
> have air density in the calculation. We should find out for sure, I don't
> have first hand knowledge. As a Davis owner/operator I want to know.
>
>
> Victor Engel wrote:
>
> OK. But I thought the latest version of Weatherlink was sending altimeter
> -- and VWS as well. Do I have a wrong understanding there?
>
> Victor
>
> On Sun, Jun 1, 2008 at 12:37 PM, Ted Lum <gladstonefamily.net at tedworld.com>
> wrote:
>
>>  You might want to re-check this thread.
>>
>> http://server.gladstonefamily.net/pipermail/wxqc/2005-November/003212.html
>>
>> Sam Drinkard wrote:
>>
>> Victor Engel wrote:
>>
>>
>>  I'm going to answer your question specifically and then also raise a
>> more generic question.
>>
>> First, it looks like your pressure reading is too low. I believe if
>> your mean error exceeds 2 millibars, you will get the message. When I
>> first set up my stations (C6155) in 2006, I noticed it tracked another
>> stations AS425 very closely in all data points, including pressure.
>> Although we tracked closely, the analysis stated our readings were too
>> low, so I made an adjustment upwards. My stations has had good QC for
>> pressure ever since.
>>
>> I wonder, though, about something. All three of us use Davis Vantage
>> Pro hardware, and all three of us were too low by similar amounts. Do
>> these stations generally ship with a slight adjustment error? Could
>> there be an adjustment needed at the factory? Certainly, we can't
>> determine this from just three data points. I'm curious of others'
>> experiences around the country, though, with this hardware.
>>
>> An alternative, of course, is that our hardware is correct and the
>> analysis is wrong. Were that to be the case, though, the airport would
>> be too high. I think that's unlikely, since aircraft rely on accurate
>> altimeter readings to navigate.
>>
>> The other thing I've noticed but haven't spent time to check is that
>> it appears the error in my readings may be correlated to temperature
>> -- the higher the temperature the lower my reading with respect to the
>> analysis. I may just be imagining that, and the magnitude of the
>> effect certainly isn't large, if present. If this really is true,
>> though, I wonder what would cause it.
>>
>> Victor C6155
>>
>>
>>
>>      Victor,
>>
>>     I've noticed the same thing with my station, which is a Davis
>> WM-II.  If I look at the long term analysis of pressure, I can see a
>> trend in the summer months that *seems* to degrade the sensor, but like
>> you, I've not investigated this aspect.  As most of us know, nearly all
>> electronic components have some variant or change with changes in the
>> component's temperature.  Perhaps it would be a starting point to
>> contact Davis and ask if there is any compensation built into the
>> pressure sensor, or if ambient air temp changes would in fact, cause the
>> sensor to not read in a non-linear fashion.
>>
>> Sam
>>
>>
>> _______________________________________________
>> wxqc mailing list
>> Post messages to wxqc at lists.gladstonefamily.net
>> To unsubcribe or change delivery options, please go to:http://server.gladstonefamily.net/mailman/listinfo/wxqc
>> To search the archives: http://www.google.com/coop/cse?cx=008314629403309390388%3Aknlfnptih9u
>>
>> The contents of this message are the responsibility of the author.
>>
>>
>>
>>
>> --
>> This message has been scanned for viruses and
>> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is
>>
>> believed to be clean.
>> _______________________________________________
>> wxqc mailing list
>> Post messages to wxqc at lists.gladstonefamily.net
>> To unsubcribe or change delivery options, please go to:
>> http://server.gladstonefamily.net/mailman/listinfo/wxqc
>> To search the archives:
>> http://www.google.com/coop/cse?cx=008314629403309390388%3Aknlfnptih9u
>>
>> The contents of this message are the responsibility of the author.
>>
>
>
> --
> This message has been scanned for viruses and
> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is
> believed to be clean.
>
> ------------------------------
>
> _______________________________________________
> wxqc mailing list
> Post messages to wxqc at lists.gladstonefamily.net
> To unsubcribe or change delivery options, please go to:http://server.gladstonefamily.net/mailman/listinfo/wxqc
> To search the archives: http://www.google.com/coop/cse?cx=008314629403309390388%3Aknlfnptih9u
>
> The contents of this message are the responsibility of the author.
>
>
>
> --
> This message has been scanned for viruses and
> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is
> believed to be clean.
>
> _______________________________________________
> wxqc mailing list
> Post messages to wxqc at lists.gladstonefamily.net
> To unsubcribe or change delivery options, please go to:
> http://server.gladstonefamily.net/mailman/listinfo/wxqc
> To search the archives:
> http://www.google.com/coop/cse?cx=008314629403309390388%3Aknlfnptih9u
>
> The contents of this message are the responsibility of the author.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://server.gladstonefamily.net/pipermail/wxqc/attachments/20080601/eef76a51/attachment.html