From jbothne at austin.rr.com  Sun Jun  1 06:56:23 2008
From: jbothne at austin.rr.com (JBothne)
Date: Sun, 1 Jun 2008 06:56:23 -0500
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
Message-ID: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>


I'm looking for assistance or direction related to the MADIS analysis of my
barometric pressure readings.  I have the Vantage 2 Pro unit and have been
uploading data since installing the unit in Oct 2005.  My readings have
always shown the same variants as compared to other stations and have
remained consistent during this time.  As of recent I have been receiveing
"MADIS rating Sensor fails L2 statistical
consistency check " yet nothing has changed.  I am looking for advice and or
direction to either resolve the issue or determine if the readings or a
result of my geographical location in relation to other site.

Regards,
Joe
Cordially,
Joseph A. Bothne
Hm: 512-259-8476
Fax: 512.259.8781
mailto:jbothne at austin.rr.com
Homepage: http://home.austin.rr.com/thebearcave/

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From brillig at gmail.com  Sun Jun  1 10:53:29 2008
From: brillig at gmail.com (Victor Engel)
Date: Sun, 1 Jun 2008 10:53:29 -0500
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
Message-ID: <e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>

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

On Sun, Jun 1, 2008 at 6:56 AM, JBothne <jbothne at austin.rr.com> wrote:

>
> I'm looking for assistance or direction related to the MADIS analysis of my
> barometric pressure readings.  I have the Vantage 2 Pro unit and have been
> uploading data since installing the unit in Oct 2005.  My readings have
> always shown the same variants as compared to other stations and have
> remained consistent during this time.  As of recent I have been receiveing
> "MADIS rating Sensor fails L2 statistical
>
> consistency check " yet nothing has changed.  I am looking for advice and
> or direction to either resolve the issue or determine if the readings or a
> result of my geographical location in relation to other site.
>
> Regards,
> Joe
> *Cordially,*
> *Joseph A. Bothne*****
> *Hm: 512-259-8476*
> *Fax: 512.259.8781*
> ***mailto:jbothne at austin.rr.com* <jbothne at austin.rr.com>********
> *Homepage: **http://home.austin.rr.com/thebearcave/*<http://home.austin.rr.com/thebearcave/>
> **
>
> _______________________________________________
> 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.
>
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From gerry.creager at tamu.edu  Sun Jun  1 11:23:51 2008
From: gerry.creager at tamu.edu (Gerry Creager)
Date: Sun, 01 Jun 2008 11:23:51 -0500
Subject: [wxqc] rotate.aprs.net
In-Reply-To: <052620080206.24340.483A1B320001609600005F1422243651029B0A02D29B9B0EBF0A050ECB99@att.net>
References: <f836cce7705b.4838ceae@optonline.net> <483967FA.3070309@tamu.edu>
	<052620080206.24340.483A1B320001609600005F1422243651029B0A02D29B9B0EBF0A050ECB99@att.net>
Message-ID: <4842CD17.7070101@tamu.edu>

Long-delayed follow-up.

Dick, you detected a server error at core-2.  We got that restarted.  As 
a result of this, I've instituted a Nagios monitor of the core servers. 
  Ted Lum had been doing this to assist us, for which we're really 
appreciative, but I needed one I could hit routinely and add more 
notifications to, so we're now there.

We shold have better response to these, as things are going to on-call 
pagers as well as e-mail now.

Please advise if you see server problems.

AS a reminder (although I think I'm preaching to the choir):
1.  Licensed Amateur Radio Operators should use rotate.aprs.net or 
rotate.aprs2.net for servers, and should use their callsign as the id 
and their passcode for verification.
2.  Other CWOP members (and Hams who do NOT want their weather data 
available via APRS RF networks) should use cwop.aprs.net for their 
servers and their CWOP ID, with a passcode of -1 (or the default for the 
software you're using).

We aggregate all the weather data from the APRS-IS Core and the 
dedicated CWOP servers and submit it to MADIS for QC and dissemination.

Passcode questions/requests can come to me or Russ Chadwick.

gerry

w4ake at att.net wrote:
> Hi Gerry: I noticed my rotation on rotate.aprs.net no longer includes 
> core-2. I rotate between 1 and 3. I also notice the packets have dropped 
> from 800+ to 100+ per hour. Has 2 started requiring verifiacation 
> numbers ? I ask because I am out of town till the end of June and am 
> running WeatherlinkIP at home while I am gone. As you know we have not 
> been able to get Davis to include the verifacation codes for Hams on 
> rotate.aprs.net so I will be off of findu if 1&3 require the codes also 
> till I get home and can get the computer back in the loop with regular 
> WL. I notice if I put a C in front of my call (CW4AKE) on IP Davis sends 
> it to findu.com on cwop.net. Of course as long as aprs 1& 3 stay open in 
> June I will be good as is.
>  
> Dick W4AKE
> 
>     -------------- Original message from Gerry Creager
>     <gerry.creager at tamu.edu>: --------------
> 
> 
>      > Jim,
>      >
>      > It's likely to be next week (after the holiday) before I can look at
>      > some of your historical QC data from MADIS. Wish I could offer a
>     better
>      > answer right now.
>      >
>      > gerry
>      >
>      > jdunaway at optonline.net wrote:
>      > > I have a quick question regarding MADIS checks.
>      > >
>      > > My station shows green checkmarks on each reading, but I have a
>      > > thumbs-down on the barometer. When I mouse-over the icon, it
>     says "MADIS
>      > > rating 61% QC OK".
>      > >
>      > > What does this mean, and how do I get the thumbs down to be two
>     thumbs
>      > > up like the rest of the readings?
>      > >
>      > > Thanks,
>      > > Jim
>      > > DW1073
>      > >
>     & gt; &g t;
>      > >
>     ------------------------------------------------------------------------
> 
>      > >
>      > > _______________________________________________
>      > > 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.
>      >
>      > --
>      > Gerry Creager -- gerry.creager at tamu.edu
>      > Texas Mesonet -- AATLT, Texas A&M University
>      > Cell: 979.229.5301 Office: 979.862.3982 FAX: 979.862.3983
>      > Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX
>     77843
>      >
>      > _______________________________________________
>      > wxqc mailing list
>      > P ost me ssages 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. 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> 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.

-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843

From sam at wa4phy.net  Sun Jun  1 11:50:28 2008
From: sam at wa4phy.net (Sam Drinkard)
Date: Sun, 01 Jun 2008 12:50:28 -0400
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
Message-ID: <4842D354.80909@wa4phy.net>



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



From sam at wa4phy.net  Sun Jun  1 11:52:29 2008
From: sam at wa4phy.net (Sam Drinkard)
Date: Sun, 01 Jun 2008 12:52:29 -0400
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
Message-ID: <4842D3CD.2090808@wa4phy.net>



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.  The other day, I was doing 
something and had the destruction manual out for the console, and 
remember reading a line or two about the pressure sensor.  It stated the 
sensor should be checked about every 6 months for correctness, as there 
could be some drift in the readings.  Perhaps that drift is in fact, 
caused by temperature change....


Sam



From deano at deanostoybox.com  Sun Jun  1 11:54:13 2008
From: deano at deanostoybox.com (David Dean)
Date: Sun, 1 Jun 2008 11:54:13 -0500
Subject: [wxqc] Status of RADAR at EWX
In-Reply-To: <e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
Message-ID: <200806011154.13878.deano@deanostoybox.com>

Hi

This is my first post to this list. I have been lurking since October 2007. I 
find the information here helpfull, informative and interesting.

My question is what's up with the RADAR at EWX? The last image available has a 
time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for 
maintenance" from time to time, but this is the longest.

Thanks in advance,

deano

CWOP CW8195 WU KTXSTAPL1
http://deanostoybox.com/weather 



From gladstonefamily.net at tedworld.com  Sun Jun  1 12:37:00 2008
From: gladstonefamily.net at tedworld.com (Ted Lum)
Date: Sun, 01 Jun 2008 13:37:00 -0400
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <4842D354.80909@wa4phy.net>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<4842D354.80909@wa4phy.net>
Message-ID: <4842DE3C.9050102@tedworld.com>

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
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From slottech at gbis.com  Sun Jun  1 12:43:49 2008
From: slottech at gbis.com (Richard)
Date: Sun, 1 Jun 2008 10:43:49 -0700
Subject: [wxqc] Status of RADAR at EWX
In-Reply-To: <200806011154.13878.deano@deanostoybox.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster><e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<200806011154.13878.deano@deanostoybox.com>
Message-ID: <E3E5F34B2FE64A29B16509B5B1FAE4B6@Richardn>

Others may have better suggestions, but I'd start by asking my local
National Weather Service office. 


Richard
www.n7tgb.net

-----Original Message-----
From: wxqc-bounces at lists.gladstonefamily.net
[mailto:wxqc-bounces at lists.gladstonefamily.net] On Behalf Of David
Dean
Sent: Sunday, June 01, 2008 9:54 AM
To: Discussion of weather data quality issues
Subject: [wxqc] Status of RADAR at EWX

Hi

This is my first post to this list. I have been lurking since October
2007. I 
find the information here helpfull, informative and interesting.

My question is what's up with the RADAR at EWX? The last image
available has a 
time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for

maintenance" from time to time, but this is the longest.

Thanks in advance,

deano

CWOP CW8195 WU KTXSTAPL1
http://deanostoybox.com/weather 


_______________________________________________
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.







From gladstonefamily.net at tedworld.com  Sun Jun  1 12:55:11 2008
From: gladstonefamily.net at tedworld.com (Ted Lum)
Date: Sun, 01 Jun 2008 13:55:11 -0400
Subject: [wxqc] Status of RADAR at EWX
In-Reply-To: <E3E5F34B2FE64A29B16509B5B1FAE4B6@Richardn>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster><e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<200806011154.13878.deano@deanostoybox.com>
	<E3E5F34B2FE64A29B16509B5B1FAE4B6@Richardn>
Message-ID: <4842E27F.9030900@tedworld.com>

This is what I see "Due to technical difficulties, the radar display is 
temporarily unavailable. Thank you for your patients. NWS Radar team" 
Which probably means that you notices the problem just before they did, 
since they have now put a message up. The radar image on the page simply 
makes a call to the NWS server so you might want to check:

http://radar.weather.gov/radar.php?rid=ewx&product=N0R&overlay=11101111&loop=no

Richard wrote:
> Others may have better suggestions, but I'd start by asking my local
> National Weather Service office. 
>
>
> Richard
> www.n7tgb.net
>
> -----Original Message-----
> From: wxqc-bounces at lists.gladstonefamily.net
> [mailto:wxqc-bounces at lists.gladstonefamily.net] On Behalf Of David
> Dean
> Sent: Sunday, June 01, 2008 9:54 AM
> To: Discussion of weather data quality issues
> Subject: [wxqc] Status of RADAR at EWX
>
> Hi
>
> This is my first post to this list. I have been lurking since October
> 2007. I 
> find the information here helpfull, informative and interesting.
>
> My question is what's up with the RADAR at EWX? The last image
> available has a 
> time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for
>
> maintenance" from time to time, but this is the longest.
>
> Thanks in advance,
>
> deano
>
> CWOP CW8195 WU KTXSTAPL1
> http://deanostoybox.com/weather 
>
>
> _______________________________________________
> 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.
>
>
>
>
>
>
> _______________________________________________
> 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, and is
believed to be clean.


From deertrail131 at aol.com  Sun Jun  1 12:40:25 2008
From: deertrail131 at aol.com (deertrail131)
Date: Sun, 1 Jun 2008 11:40:25 -0600 (Mountain Daylight Time)
Subject: [wxqc] Status of RADAR at EWX
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<200806011154.13878.deano@deanostoybox.com>
Message-ID: <4842DF09.000009.00604@RON>

Deano:



Check the link below, then click on your area and see if it is working. I
looks good from Colorado. But, I might be looking in the wrong area......?? 



RADAR Loop: Austin ^ San Antonio Texas.



http://radar.weather.gov/Conus/full_loop.php



I cannot fine it with the Radar Loop...? http://usasearch
gov/search?v%3Aproject=firstgov&query=San+Antonio+Texas&affiliate=nws.noaa
gov



Ron  WD0BDQ



-------Original Message-------

 

From: David Dean

Date: 06/01/08 10:55:40

To: Discussion of weather data quality issues

Subject: [wxqc] Status of RADAR at EWX

 

Hi

 

This is my first post to this list. I have been lurking since October 2007.
I

find the information here helpfull, informative and interesting.

 

My question is what's up with the RADAR at EWX? The last image available has
a

time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for

maintenance" from time to time, but this is the longest.

 

Thanks in advance,

 

deano

 

CWOP CW8195 WU KTXSTAPL1

http://deanostoybox.com/weather

 

 

_______________________________________________

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

 

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From brillig at gmail.com  Sun Jun  1 13:20:25 2008
From: brillig at gmail.com (Victor Engel)
Date: Sun, 1 Jun 2008 13:20:25 -0500
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <4842DE3C.9050102@tedworld.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<4842D354.80909@wa4phy.net> <4842DE3C.9050102@tedworld.com>
Message-ID: <e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>

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.
>
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From gladstonefamily.net at tedworld.com  Sun Jun  1 13:31:02 2008
From: gladstonefamily.net at tedworld.com (Ted Lum)
Date: Sun, 01 Jun 2008 14:31:02 -0400
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<4842D354.80909@wa4phy.net>
	<4842DE3C.9050102@tedworld.com>
	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
Message-ID: <4842EAE6.4030604@tedworld.com>

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 
> <http://gladstonefamily.net>@tedworld.com <http://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 <mailto: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
>     <mailto: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:
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>
> The contents of this message are the responsibility of the author.


-- 
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From deertrail131 at aol.com  Sun Jun  1 13:16:11 2008
From: deertrail131 at aol.com (deertrail131)
Date: Sun, 1 Jun 2008 12:16:11 -0600 (Mountain Daylight Time)
Subject: [wxqc] Status of RADAR at EWX
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<200806011154.13878.deano@deanostoybox.com> <4842DF09.000009.00604@RON>
Message-ID: <4842E76B.00000F.00604@RON>

It does look like that Radar is down or just not working with Austin ^ San
Antonio Texas.

 

http://forecast.weather.gov/MapClick
php?CityName=Austin&state=TX&site=EWX&textField1=30.267&textField2=-97.743

 

http://forecast.weather.gov/MapClick
php?CityName=San+Antonio&state=TX&site=EWX&textField1=29.4577&textField2=-98
5054

 

Ron WD0BDQ

 

 

-------Original Message-------

 

From: deertrail131

Date: 6/1/2008 11:57:46 AM

To: Discussion of weather data quality issues

Cc: wd0bdq

Subject: Re: [wxqc] Status of RADAR at EWX

 

Deano:

 

Check the link below, then click on your area and see if it is working. I
looks good from Colorado. But, I might be looking in the wrong area......?? 

 

RADAR Loop: Austin ^ San Antonio Texas.

 

http://radar.weather.gov/Conus/full_loop.php

 

I cannot fine it with the Radar Loop...? http://usasearch
gov/search?v%3Aproject=firstgov&query=San+Antonio+Texas&affiliate=nws.noaa
gov

 

Ron  WD0BDQ

 

-------Original Message-------

 

From: David Dean

Date: 06/01/08 10:55:40

To: Discussion of weather data quality issues

Subject: [wxqc] Status of RADAR at EWX

 

Hi

 

This is my first post to this list. I have been lurking since October 2007.
I

find the information here helpfull, informative and interesting.

 

My question is what's up with the RADAR at EWX? The last image available has
a

time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for

maintenance" from time to time, but this is the longest.

 

Thanks in advance,

 

deano

 

CWOP CW8195 WU KTXSTAPL1

http://deanostoybox.com/weather

 

 

_______________________________________________

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.

 

 
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From brillig at gmail.com  Sun Jun  1 13:48:35 2008
From: brillig at gmail.com (Victor Engel)
Date: Sun, 1 Jun 2008 13:48:35 -0500
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <4842EAE6.4030604@tedworld.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<4842D354.80909@wa4phy.net> <4842DE3C.9050102@tedworld.com>
	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
	<4842EAE6.4030604@tedworld.com>
Message-ID: <e0e999680806011148h71d45d28x629192be348d1075@mail.gmail.com>

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:
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From gladstonefamily.net at tedworld.com  Sun Jun  1 14:03:14 2008
From: gladstonefamily.net at tedworld.com (Ted Lum)
Date: Sun, 01 Jun 2008 15:03:14 -0400
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <e0e999680806011148h71d45d28x629192be348d1075@mail.gmail.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<4842D354.80909@wa4phy.net>
	<4842DE3C.9050102@tedworld.com>	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>	<4842EAE6.4030604@tedworld.com>
	<e0e999680806011148h71d45d28x629192be348d1075@mail.gmail.com>
Message-ID: <4842F272.8040308@tedworld.com>

Readme.txt (readme.wri) in WeatherLink root goes back as far as v5.6. I 
do see this under 5.7:

"For Vantage Pro console, altimeter setting is reported instead of 
barometer in the APRS string."

Maybe they didn't say what they mean. In any event, if you are seeing 
temperature driven variation in APRS pressure then something is wrong. 
The pressure sensor is indoors and cannot be affected by OAT. No OAT 
correction should be happening in software for APRS pressure.

Victor Engel wrote:
> 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 
> <http://gladstonefamily.net>@tedworld.com <http://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
>>     <http://gladstonefamily.net>@tedworld.com <http://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 <mailto:wxqc at lists.gladstonefamily.net>
>>>         To unsubcribe or change delivery options, please go to:
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>>>
>>>         The contents of this message are the responsibility of the author.
>>>
>>>           
>>
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>>         This message has been scanned for viruses and
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From m.c.crockett at roadrunner.com  Sun Jun  1 14:08:54 2008
From: m.c.crockett at roadrunner.com (Merton Campbell Crockett)
Date: Sun, 1 Jun 2008 12:08:54 -0700
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <4842EAE6.4030604@tedworld.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<4842D354.80909@wa4phy.net>
	<4842DE3C.9050102@tedworld.com>
	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
	<4842EAE6.4030604@tedworld.com>
Message-ID: <4F39AFC4-5B22-4D3A-A7A5-D53ECAB90108@roadrunner.com>

Davis Instruments' Application Note 28 explains how the barometric  
pressure that is reported is derived.  The barometric pressure  
reported has been reduced to report sea level barometric pressure.  On  
page 11 at the end of the discussion of barometric pressure, a formula  
is provided for converting the reported barometric pressure to the  
altimeter reading used for CWOP reports.

I don't understand, exactly, how temperature effects the pressure  
sensor in the Davis Instruments Vantage Pro2 console but my station  
tends to report higher barometric pressures in the afternoon.  The  
console is in a room with cathedral ceilings on the west side of the  
house.  The room heats up in the afternoon and doesn't cool down until  
mid-evening.  During this period, the QC graphs show the widest  
divergence between my readings and the predicted values.

Merton Campbell Crockett


On 01 Jun 2008, at 11:31:02, Ted Lum 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, 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, 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, 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.

Merton Campbell Crockett
m.c.crockett at roadrunner.com



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From chenry at smithville.net  Sun Jun  1 13:10:36 2008
From: chenry at smithville.net (Chuck Henry)
Date: Sun, 01 Jun 2008 14:10:36 -0400
Subject: [wxqc] Status of RADAR at EWX
In-Reply-To: <200806011154.13878.deano@deanostoybox.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<200806011154.13878.deano@deanostoybox.com>
Message-ID: <4842E61C.4070005@smithville.net>

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From Evan.Bookbinder at noaa.gov  Sun Jun  1 14:23:15 2008
From: Evan.Bookbinder at noaa.gov (Evan Bookbinder)
Date: Sun, 01 Jun 2008 14:23:15 -0500
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <4F39AFC4-5B22-4D3A-A7A5-D53ECAB90108@roadrunner.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<4842D354.80909@wa4phy.net> <4842DE3C.9050102@tedworld.com>
	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
	<4842EAE6.4030604@tedworld.com>
	<4F39AFC4-5B22-4D3A-A7A5-D53ECAB90108@roadrunner.com>
Message-ID: <004801c8c41c$f0ede4f0$6901a8c0@stormalerthp>

> 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.
 
The location of the sensor indoors has nothing to do with the fact the
barometric pressure *is* impacted by outside air temperature. Air pressure
is the weight of a column of air above a sensor. 99.999% of the air weight
is not in your house, it's outside. Barometric pressure is VERY MUCH altered
by outside temperature. Because we're not dealing with an enclosed volume of
space, when you heat the air, molecules expand and thus there are less of
them in a given volume of space. As such, the pressure falls. When you cool
the air, air molecules contract, occupying more per unit volume and thus
weight more (pressure increase). 
 
In the absence of any significant airmass changes, a diurnal barometric
pressure curve will show a MINIMUM in the mid afternoon at peak heating, and
a maximum around daybreak during peak COOLING. This is for outdoors, with
the greatest impact occuring where there are the most air molecules -- in
the lower atmosphere. Changes to air temperature INSIDE your home are
generally considered negligeble given the vertical depth of air in your home
when compared to the entire atmosphere above you (yes, even with cathedral
ceilings).
 
All things considered equal however, you should not be seeing the barometer
rise in the afternoon, unless you are a coastal location experiencing an
afternoon seabreeze (which is accompanied by a drop in air temperature and
rise in pressure).
 
Evan
 
 
 
 
 


  _____  

From: wxqc-bounces at lists.gladstonefamily.net
[mailto:wxqc-bounces at lists.gladstonefamily.net] On Behalf Of Merton Campbell
Crockett
Sent: Sunday, June 01, 2008 2:09 PM
To: Discussion of weather data quality issues
Subject: Re: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US


Davis Instruments' Application Note 28 explains how the barometric pressure
that is reported is derived.  The barometric pressure reported has been
reduced to report sea level barometric pressure.  On page 11 at the end of
the discussion of barometric pressure, a formula is provided for converting
the reported barometric pressure to the altimeter reading used for CWOP
reports. 

I don't understand, exactly, how temperature effects the pressure sensor in
the Davis Instruments Vantage Pro2 console but my station tends to report
higher barometric pressures in the afternoon.  The console is in a room with
cathedral ceilings on the west side of the house.  The room heats up in the
afternoon and doesn't cool down until mid-evening.  During this period, the
QC graphs show the widest divergence between my readings and the predicted
values.

Merton Campbell Crockett



On 01 Jun 2008, at 11:31:02, Ted Lum 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

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The contents of this message are the responsibility of the author.



  


-- 
This message has been scanned for viruses and 
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_______________________________________________
wxqc mailing list
Post messages to wxqc at lists.gladstonefamily.net
To unsubcribe or change delivery options, please go to:
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The contents of this message are the responsibility of the author.




-- 
This message has been scanned for viruses and 
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  _____  


_______________________________________________

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Post messages to wxqc at lists.gladstonefamily.net

To unsubcribe or change delivery options, please go to:

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The contents of this message are the responsibility of the author.



-- 
This message has been scanned for viruses and 
dangerous content by  <http://www.mailscanner.info/> MailScanner, 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:
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Merton Campbell Crockett
m.c.crockett at roadrunner.com




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From webmaster at saratoga-weather.org  Sun Jun  1 14:42:32 2008
From: webmaster at saratoga-weather.org (Ken True)
Date: Sun, 01 Jun 2008 12:42:32 -0700
Subject: [wxqc] Status of RADAR at EWX
In-Reply-To: <200806011154.13878.deano@deanostoybox.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<200806011154.13878.deano@deanostoybox.com>
Message-ID: <4842FBA8.3000304@saratoga-weather.org>

If you have PHP available on your weather website, you can use a small 
script I wrote to show the status of the NEXRAD radar site.
Script is available from 
http://saratoga-weather.org/scripts-NEXRAD.php#NEXRADStatus

Using it by invoking (on my site) 
http://saratoga-weather.org/radar-status.php?nexrad=KEWX

shows

NEXRAD Radar KEWX status: No Data [last data 80189 secs ago] as of Sun, 
01-Jun-2008 12:34pm PDT

You can customize the script on your site for local timezone and default 
NEXRAD site id.

Best regards,
Ken
CW1792

David Dean wrote:
> Hi
>
> This is my first post to this list. I have been lurking since October 2007. I 
> find the information here helpfull, informative and interesting.
>
> My question is what's up with the RADAR at EWX? The last image available has a 
> time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for 
> maintenance" from time to time, but this is the longest.
>
> Thanks in advance,
>
> deano
>
> CWOP CW8195 WU KTXSTAPL1
> http://deanostoybox.com/weather 
>
>
> _______________________________________________
> 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.
>   

From brillig at gmail.com  Sun Jun  1 14:47:22 2008
From: brillig at gmail.com (Victor Engel)
Date: Sun, 1 Jun 2008 14:47:22 -0500
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <004801c8c41c$f0ede4f0$6901a8c0@stormalerthp>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<4842D354.80909@wa4phy.net> <4842DE3C.9050102@tedworld.com>
	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
	<4842EAE6.4030604@tedworld.com>
	<4F39AFC4-5B22-4D3A-A7A5-D53ECAB90108@roadrunner.com>
	<004801c8c41c$f0ede4f0$6901a8c0@stormalerthp>
Message-ID: <e0e999680806011247s471dda47j79b115bab9e0f281@mail.gmail.com>

Please note that when I said I noticed a suspected variation in pressure, I
was referring to the difference between my reading and the analysis, not a
variation in pressure. I know there is a daily fluctuation in pressure.
Presumably it should be the same for everyone in the vicinity.

Also, just because a sensor is indoors doesn't mean that it's immune to
temperature variations. Such a notion presumes indoor temperature is
constant. Over the past 6 months or so my indoor temperature has varied from
about 46 to 86. I allow indoor temperature to vary for economical reasons.

Anyway, I haven't confirmed the effect I described. It might not even be
there. What I seem to notice, though, is that my readings are more likely to
be lower than the analysis during warm weather than during cold weather. The
difference is slight, since my QC tends to hover between 98% and 100% for
barometer.

Perhaps I shouldn't have brought it up at all until I verified it.

Victor

On Sun, Jun 1, 2008 at 2:23 PM, Evan Bookbinder <Evan.Bookbinder at noaa.gov>
wrote:

>  > 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.
>
> The location of the sensor indoors has nothing to do with the fact the
> barometric pressure *is* impacted by outside air temperature. Air pressure
> is the weight of a column of air above a sensor. 99.999% of the air weight
> is not in your house, it's outside. Barometric pressure is VERY MUCH altered
> by outside temperature. Because we're not dealing with an enclosed volume of
> space, when you heat the air, molecules expand and thus there are less of
> them in a given volume of space. As such, the pressure falls. When you cool
> the air, air molecules contract, occupying more per unit volume and thus
> weight more (pressure increase).
>
> In the absence of any significant airmass changes, a diurnal barometric
> pressure curve will show a MINIMUM in the mid afternoon at peak heating, and
> a maximum around daybreak during peak COOLING. This is for outdoors, with
> the greatest impact occuring where there are the most air molecules -- in
> the lower atmosphere. Changes to air temperature INSIDE your home are
> generally considered negligeble given the vertical depth of air in your home
> when compared to the entire atmosphere above you (yes, even with cathedral
> ceilings).
>
> All things considered equal however, you should not be seeing the barometer
> rise in the afternoon, unless you are a coastal location experiencing an
> afternoon seabreeze (which is accompanied by a drop in air temperature and
> rise in pressure).
>
> Evan
>
>
>
>
>
>
>  ------------------------------
> *From:* wxqc-bounces at lists.gladstonefamily.net [mailto:
> wxqc-bounces at lists.gladstonefamily.net] *On Behalf Of *Merton Campbell
> Crockett
> *Sent:* Sunday, June 01, 2008 2:09 PM
> *To:* Discussion of weather data quality issues
> *Subject:* Re: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX
> US
>
> Davis Instruments' Application Note 28 explains how the barometric pressure
> that is reported is derived.  The barometric pressure reported has been
> reduced to report sea level barometric pressure.  On page 11 at the end of
> the discussion of barometric pressure, a formula is provided for converting
> the reported barometric pressure to the altimeter reading used for CWOP
> reports.
> I don't understand, exactly, how temperature effects the pressure sensor in
> the Davis Instruments Vantage Pro2 console but my station tends to report
> higher barometric pressures in the afternoon.  The console is in a room with
> cathedral ceilings on the west side of the house.  The room heats up in the
> afternoon and doesn't cool down until mid-evening.  During this period, the
> QC graphs show the widest divergence between my readings and the predicted
> values.
>
> Merton Campbell Crockett
>
>
>  On 01 Jun 2008, at 11:31:02, Ted Lum 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.
>
>
>  Merton Campbell Crockett
> m.c.crockett at roadrunner.com
>
>
>
>
> _______________________________________________
> 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.
>
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From deano at deanostoybox.com  Sun Jun  1 14:48:42 2008
From: deano at deanostoybox.com (David Dean)
Date: Sun, 1 Jun 2008 14:48:42 -0500
Subject: [wxqc] Status of RADAR at EWX
In-Reply-To: <4842E61C.4070005@smithville.net>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<200806011154.13878.deano@deanostoybox.com>
	<4842E61C.4070005@smithville.net>
Message-ID: <200806011448.42897.deano@deanostoybox.com>

On Sunday 01 June 2008 01:10:36 pm Chuck Henry wrote:
> From NWSFO Austin/San Antonio TX:
> A major component has failed on the National Weather
> Service, KEWX, WSR-88D radar in New Braunfels, Texas.
> Estimated time for completion of repairs will be June
> 5, 2008. Weather surveillance coverage will remain in place
> utilizing the weather radars in Granger, 

Thanks a bunch. That is what I was looking for. I know there is supposed to be 
a text product available to the public with that information, but I have been 
unable to find it.

later
deano


From deertrail131 at aol.com  Sun Jun  1 14:52:41 2008
From: deertrail131 at aol.com (deertrail131)
Date: Sun, 1 Jun 2008 13:52:41 -0600 (Mountain Daylight Time)
Subject: [wxqc] Status of RADAR at EWX
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<200806011154.13878.deano@deanostoybox.com>
	<4842FBA8.3000304@saratoga-weather.org>
Message-ID: <4842FE03.00000F.05848@RON>

Sounds like a lot of work and trouble..............when the Radar site is
down.  

NEXRAD Radar KEWX status: No Data [last data 81089 secs ago] as of Sun,
01-Jun-2008 12:49pm PDT

NWS WSR-88D Transmit/Receive Status

Ron DW0573 http://www.findu.com/cgi-bin/wxpage.cgi?DW0573

-------Original Message-------

 

From: Ken True

Date: 6/1/2008 1:43:39 PM

To: Discussion of weather data quality issues

Subject: Re: [wxqc] Status of RADAR at EWX

 

If you have PHP available on your weather website, you can use a small

script I wrote to show the status of the NEXRAD radar site.

Script is available from

http://saratoga-weather.org/scripts-NEXRAD.php#NEXRADStatus

 

Using it by invoking (on my site)

http://saratoga-weather.org/radar-status.php?nexrad=KEWX

 

shows

 

NEXRAD Radar KEWX status: No Data [last data 80189 secs ago] as of Sun,

01-Jun-2008 12:34pm PDT

 

You can customize the script on your site for local timezone and default

NEXRAD site id.

 

Best regards,

Ken

CW1792

 

David Dean wrote:

> Hi

>

> This is my first post to this list. I have been lurking since October 2007
 I

> find the information here helpfull, informative and interesting.

>

> My question is what's up with the RADAR at EWX? The last image available
has a

> time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for

> maintenance" from time to time, but this is the longest.

>

> Thanks in advance,

>

> deano

>

> CWOP CW8195 WU KTXSTAPL1

> http://deanostoybox.com/weather

>

>

> _______________________________________________

> 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.

>

_______________________________________________

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.

 
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From brillig at gmail.com  Sun Jun  1 14:53:51 2008
From: brillig at gmail.com (Victor Engel)
Date: Sun, 1 Jun 2008 14:53:51 -0500
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <e0e999680806011247s471dda47j79b115bab9e0f281@mail.gmail.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>
	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>
	<4842D354.80909@wa4phy.net> <4842DE3C.9050102@tedworld.com>
	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
	<4842EAE6.4030604@tedworld.com>
	<4F39AFC4-5B22-4D3A-A7A5-D53ECAB90108@roadrunner.com>
	<004801c8c41c$f0ede4f0$6901a8c0@stormalerthp>
	<e0e999680806011247s471dda47j79b115bab9e0f281@mail.gmail.com>
Message-ID: <e0e999680806011253n273bf57fh48ff92e6ba08f198@mail.gmail.com>

I guess the 52 week analysis graphs would be appropriate for this
discussion. Here's the graph for my station:

http://weather.gladstonefamily.net/site/C6155?tile=10;days=364#Data

Victor

On Sun, Jun 1, 2008 at 2:47 PM, Victor Engel <brillig at gmail.com> wrote:

> Please note that when I said I noticed a suspected variation in pressure, I
> was referring to the difference between my reading and the analysis, not a
> variation in pressure. I know there is a daily fluctuation in pressure.
> Presumably it should be the same for everyone in the vicinity.
>
> Also, just because a sensor is indoors doesn't mean that it's immune to
> temperature variations. Such a notion presumes indoor temperature is
> constant. Over the past 6 months or so my indoor temperature has varied from
> about 46 to 86. I allow indoor temperature to vary for economical reasons.
>
> Anyway, I haven't confirmed the effect I described. It might not even be
> there. What I seem to notice, though, is that my readings are more likely to
> be lower than the analysis during warm weather than during cold weather. The
> difference is slight, since my QC tends to hover between 98% and 100% for
> barometer.
>
> Perhaps I shouldn't have brought it up at all until I verified it.
>
> Victor
>
>
> On Sun, Jun 1, 2008 at 2:23 PM, Evan Bookbinder <Evan.Bookbinder at noaa.gov>
> wrote:
>
>>  > 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.
>>
>> The location of the sensor indoors has nothing to do with the fact the
>> barometric pressure *is* impacted by outside air temperature. Air pressure
>> is the weight of a column of air above a sensor. 99.999% of the air weight
>> is not in your house, it's outside. Barometric pressure is VERY MUCH altered
>> by outside temperature. Because we're not dealing with an enclosed volume of
>> space, when you heat the air, molecules expand and thus there are less of
>> them in a given volume of space. As such, the pressure falls. When you cool
>> the air, air molecules contract, occupying more per unit volume and thus
>> weight more (pressure increase).
>>
>> In the absence of any significant airmass changes, a diurnal barometric
>> pressure curve will show a MINIMUM in the mid afternoon at peak heating, and
>> a maximum around daybreak during peak COOLING. This is for outdoors, with
>> the greatest impact occuring where there are the most air molecules -- in
>> the lower atmosphere. Changes to air temperature INSIDE your home are
>> generally considered negligeble given the vertical depth of air in your home
>> when compared to the entire atmosphere above you (yes, even with cathedral
>> ceilings).
>>
>> All things considered equal however, you should not be seeing the
>> barometer rise in the afternoon, unless you are a coastal location
>> experiencing an afternoon seabreeze (which is accompanied by a drop in air
>> temperature and rise in pressure).
>>
>> Evan
>>
>>
>>
>>
>>
>>
>>  ------------------------------
>> *From:* wxqc-bounces at lists.gladstonefamily.net [mailto:
>> wxqc-bounces at lists.gladstonefamily.net] *On Behalf Of *Merton Campbell
>> Crockett
>> *Sent:* Sunday, June 01, 2008 2:09 PM
>> *To:* Discussion of weather data quality issues
>> *Subject:* Re: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX
>> US
>>
>> Davis Instruments' Application Note 28 explains how the barometric
>> pressure that is reported is derived.  The barometric pressure reported has
>> been reduced to report sea level barometric pressure.  On page 11 at the end
>> of the discussion of barometric pressure, a formula is provided for
>> converting the reported barometric pressure to the altimeter reading used
>> for CWOP reports.
>> I don't understand, exactly, how temperature effects the pressure sensor
>> in the Davis Instruments Vantage Pro2 console but my station tends to report
>> higher barometric pressures in the afternoon.  The console is in a room with
>> cathedral ceilings on the west side of the house.  The room heats up in the
>> afternoon and doesn't cool down until mid-evening.  During this period, the
>> QC graphs show the widest divergence between my readings and the predicted
>> values.
>>
>> Merton Campbell Crockett
>>
>>
>>  On 01 Jun 2008, at 11:31:02, Ted Lum 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@
>> 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.
>>
>>
>>  Merton Campbell Crockett
>> m.c.crockett at roadrunner.com
>>
>>
>>
>>
>> _______________________________________________
>> 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.
>>
>
>
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From steve at softwx.com  Sun Jun  1 14:11:49 2008
From: steve at softwx.com (Steve)
Date: Sun, 1 Jun 2008 13:11:49 -0600
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <4842EAE6.4030604@tedworld.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<4842D354.80909@wa4phy.net><4842DE3C.9050102@tedworld.com><e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>
	<4842EAE6.4030604@tedworld.com>
Message-ID: <EBA3D9438D354921B3D1B44FDAEEE47C@shrek>

The recent version (5.7, I believe) of the WeatherLink software has the fix to send altimeter instead of the console's sea level pressure.  The fix is in the WeatherLink software itself. I think I remember seeing that they made a firmware change to the APRS data logger, but for the vast majority of VP data loggers that people have, there is nothing changed in the firmware related to this issue. 

I tested the WeatherLink software change they made and verified that it does do the altimeter conversion as they say. 

If you are using an older version of WeatherLink, or using another software program that does not properly calculate and send altimeter, then temperature definitely can have an effect on your CWOP pressure. The VP console calculates the displayed pressure value (which is sea level pressure) by taking the raw sensor pressure and applying a formula that also includes temperature and humidity as inputs.

Steve
SoftWx
  ----- Original Message ----- 
  From: Ted Lum 
  To: Discussion of weather data quality issues 
  Sent: 06/01/2008 12:31 PM
  Subject: Re: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US


  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


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From webmaster at saratoga-weather.org  Sun Jun  1 15:03:04 2008
From: webmaster at saratoga-weather.org (Ken True)
Date: Sun, 01 Jun 2008 13:03:04 -0700
Subject: [wxqc] Status of RADAR at EWX
In-Reply-To: <4842FE03.00000F.05848@RON>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<200806011154.13878.deano@deanostoybox.com>
	<4842FBA8.3000304@saratoga-weather.org> <4842FE03.00000F.05848@RON>
Message-ID: <48430078.7060502@saratoga-weather.org>

Really no trouble at all.. if you have a personal weather website with 
PHP, you can have the script invoked on your radar page ( like mine at 
http://saratoga-weather.org/radar.php ) in 'don't display if radar is 
active' mode.
When a radar issue crops up, a box is displayed at the top of the page 
with the status and any text messages about the radar from NOAA.  It 
just helps the viewers of the radar images on your site to see that the 
data may be stale, and why it is so (if NOAA has text messages about the 
outage).

Regards,
Ken
CW1792
http://saratoga-weather.org/

deertrail131 wrote:
> Sounds like a lot of work and trouble..............when the Radar site is
> down.  
>
> NEXRAD Radar KEWX status: No Data [last data 81089 secs ago] as of Sun,
> 01-Jun-2008 12:49pm PDT
>
> NWS WSR-88D Transmit/Receive Status
>
> Ron DW0573 http://www.findu.com/cgi-bin/wxpage.cgi?DW0573
>
> -------Original Message-------
>
>  
>
> From: Ken True
>
> Date: 6/1/2008 1:43:39 PM
>
> To: Discussion of weather data quality issues
>
> Subject: Re: [wxqc] Status of RADAR at EWX
>
>  
>
> If you have PHP available on your weather website, you can use a small
>
> script I wrote to show the status of the NEXRAD radar site.
>
> Script is available from
>
> http://saratoga-weather.org/scripts-NEXRAD.php#NEXRADStatus
>
>  
>
> Using it by invoking (on my site)
>
> http://saratoga-weather.org/radar-status.php?nexrad=KEWX
>
>  
>
> shows
>
>  
>
> NEXRAD Radar KEWX status: No Data [last data 80189 secs ago] as of Sun,
>
> 01-Jun-2008 12:34pm PDT
>
>  
>
> You can customize the script on your site for local timezone and default
>
> NEXRAD site id.
>
>  
>
> Best regards,
>
> Ken
>
> CW1792
>
>  
>
> David Dean wrote:
>
>   
>> Hi
>>     
>
>   
>
>   
>> This is my first post to this list. I have been lurking since October 2007
>>     
>  I
>
>   
>> find the information here helpfull, informative and interesting.
>>     
>
>   
>
>   
>> My question is what's up with the RADAR at EWX? The last image available
>>     
> has a
>
>   
>> time stamp of 2007 05 21  21:17 UTC. I am used to seeing the "down for
>>     
>
>   
>> maintenance" from time to time, but this is the longest.
>>     
>
>   
>
>   
>> Thanks in advance,
>>     
>
>   
>
>   
>> deano
>>     
>
>   
>
>   
>> CWOP CW8195 WU KTXSTAPL1
>>     
>
>   
>> http://deanostoybox.com/weather
>>     
>
>   
>
>   
>
>   
>> _______________________________________________
>>     
>
>   
>> 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.
>>     
>
>   
>
> _______________________________________________
>
> 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.
>
>  
>
>   

From gladstonefamily.net at tedworld.com  Sun Jun  1 16:01:19 2008
From: gladstonefamily.net at tedworld.com (Ted Lum)
Date: Sun, 01 Jun 2008 17:01:19 -0400
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <004801c8c41c$f0ede4f0$6901a8c0@stormalerthp>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<4842D354.80909@wa4phy.net>
	<4842DE3C.9050102@tedworld.com>	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>	<4842EAE6.4030604@tedworld.com>	<4F39AFC4-5B22-4D3A-A7A5-D53ECAB90108@roadrunner.com>
	<004801c8c41c$f0ede4f0$6901a8c0@stormalerthp>
Message-ID: <48430E1F.3080504@tedworld.com>

That's right. What I mean to say is that since the pressure data which 
should be sent to APRS is altimeter (which is only altitude and not 
temperature corrected from the sensors raw reading) we should see no 
variation due to OAT from the actual local reference altimeter. In other 
words, we assume altimeter will vary based on OAT to begin with, what we 
would not expect would be variation from a local altimeter references 
from either a correction (software) or stray variation (sensor or 
electronics drift). The complaint here is that a station is not tracking 
to other local stations. Assuming that all stations are reporting 
altimeter, and are seeing the same variation in altimeter due to 
temperature, then any single station showing variation from the sample 
group with respect to temperature would be suspect. When I say variation 
I AM NOT referring to "a" stations pressure, I am referring to the delta 
withing the control group. I apologize for my oversimplification.

So, we assume altimeter is affected by OAT and we assume that we know 
what the local altimeter reference is. We know that the Davis pressure 
sensor is in the console, not the station, which is inside and (likely) 
in a climate controlled environment that would limit thermal variation 
of the sensor or electronics. So, statically significant altimeter 
variation from the local altimeter standard that correlates to OAT would 
likely be caused by some software correction. Now, if the room 
temperature is highly variable, and the delta variation correlates to 
room temperature then there is a likelihood you're looking at thermal 
drift in the sensor or electronics. Also, a positive pressure drift with 
respect to a positive temperature swing is typical of a correction since 
the actual effect of temperature on atmospheric pressure is the inverse, 
although this might also be indicative of sensor or electronics drift. 
The problem here is that we are comparing to a control group and not a 
local calibrated, traceable, standard, and it could just as easily be a 
problem with the control group as with the single station.


Evan Bookbinder wrote:
> > 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.
>  
> The location of the sensor indoors has nothing to do with the fact the 
> barometric pressure *is* impacted by outside air temperature. Air 
> pressure is the weight of a column of air above a sensor. 99.999% of 
> the air weight is not in your house, it's outside. Barometric pressure 
> is VERY MUCH altered by outside temperature. Because we're not dealing 
> with an enclosed volume of space, when you heat the air, molecules 
> expand and thus there are less of them in a given volume of space. As 
> such, the pressure falls. When you cool the air, air molecules 
> contract, occupying more per unit volume and thus weight more 
> (pressure increase).
>  
> In the absence of any significant airmass changes, a diurnal 
> barometric pressure curve will show a MINIMUM in the mid afternoon at 
> peak heating, and a maximum around daybreak during peak COOLING. This 
> is for outdoors, with the greatest impact occuring where there are the 
> most air molecules -- in the lower atmosphere. Changes to air 
> temperature INSIDE your home are generally considered negligeble given 
> the vertical depth of air in your home when compared to the entire 
> atmosphere above you (yes, even with cathedral ceilings).
>  
> All things considered equal however, you should not be seeing the 
> barometer rise in the afternoon, unless you are a coastal location 
> experiencing an afternoon seabreeze (which is accompanied by a drop in 
> air temperature and rise in pressure).
>  
> Evan
>  
>  
>  
>  
>  
>
>     ------------------------------------------------------------------------
>     *From:* wxqc-bounces at lists.gladstonefamily.net
>     [mailto:wxqc-bounces at lists.gladstonefamily.net] *On Behalf Of
>     *Merton Campbell Crockett
>     *Sent:* Sunday, June 01, 2008 2:09 PM
>     *To:* Discussion of weather data quality issues
>     *Subject:* Re: [wxqc] CWOP Information for CW4490 (C4490) in
>     Leander, TX US
>
>     Davis Instruments' Application Note 28 explains how the barometric
>     pressure that is reported is derived.  The barometric pressure
>     reported has been reduced to report sea level barometric pressure.
>      On page 11 at the end of the discussion of barometric pressure, a
>     formula is provided for converting the reported barometric
>     pressure to the altimeter reading used for CWOP reports.
>
>     I don't understand, exactly, how temperature effects the pressure
>     sensor in the Davis Instruments Vantage Pro2 console but my
>     station tends to report higher barometric pressures in the
>     afternoon.  The console is in a room with cathedral ceilings on
>     the west side of the house.  The room heats up in the afternoon
>     and doesn't cool down until mid-evening.  During this period, the
>     QC graphs show the widest divergence between my readings and the
>     predicted values.
>
>     Merton Campbell Crockett
>
>
>     On 01 Jun 2008, at 11:31:02, Ted Lum 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
>>>     <http://gladstonefamily.net>@tedworld.com <http://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 <mailto:wxqc at lists.gladstonefamily.net>
>>>>         To unsubcribe or change delivery options, please go to:
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>>>>         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*
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>>>         _______________________________________________
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>>>         The contents of this message are the responsibility of the
>>>         author.
>>>
>>>
>>>
>>>     -- 
>>>     This message has been scanned for viruses and
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>>>     _______________________________________________
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>>>     The contents of this message are the responsibility of the author.
>>
>>
>>     -- 
>>     This message has been scanned for viruses and
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>>     believed to be clean. _______________________________________________
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>>     The contents of this message are the responsibility of the author.
>
>     Merton Campbell Crockett
>     m.c.crockett at roadrunner.com <mailto:m.c.crockett at roadrunner.com>
>
>
>
>
> -- 
> This message has been scanned for viruses and
> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is
> believed to be clean.
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From jhlists at earthlink.net  Sun Jun  1 16:45:53 2008
From: jhlists at earthlink.net (Radiocatus)
Date: Sun, 01 Jun 2008 14:45:53 -0700
Subject: [wxqc] CWOP Information for CW4490 (C4490) in Leander, TX US
In-Reply-To: <e0e999680806011247s471dda47j79b115bab9e0f281@mail.gmail.com>
References: <000001c8c3de$83f7a4a0$6401a8c0@ossomaster>	<e0e999680806010853g6e0f3cbah679b513ffdd127a0@mail.gmail.com>	<4842D354.80909@wa4phy.net>
	<4842DE3C.9050102@tedworld.com>	<e0e999680806011120o70ed57dds75e35ed2610a80b7@mail.gmail.com>	<4842EAE6.4030604@tedworld.com>	<4F39AFC4-5B22-4D3A-A7A5-D53ECAB90108@roadrunner.com>	<004801c8c41c$f0ede4f0$6901a8c0@stormalerthp>
	<e0e999680806011247s471dda47j79b115bab9e0f281@mail.gmail.com>
Message-ID: <48431891.3040301@earthlink.net>

I, too, have a Davis VP2, and obsessed for a while about variations in 
my readings from the MADIS analysis. I finally decided to use the 
pressure from KONT (Ontario International), about 10 miles away as an 
indicator since should be regularly serviced and calibrated. My VP2 
stays within about 0.2mb of KONT, although the MADIS analysis varies a 
bit due to the several PWS that are included in the analysis.  KPOC 
(Brackett Field) is only about a mile away, but it no longer reports 
temperature, humidity, or rainfall, the anemometer jumps directly from 0 
to 6mph (bad bearings?), and only reports during tower hours. I don't 
trust it.

I've concluded that my temperature and humidity/dewpoint variations are 
due to microclimate variations stemming from my proximity to a large 
reservoir (Puddingstone) about 1.5 miles from my location and upwind 
from me most of the time. MADIS has fits with that.

-Jay AS789

Victor Engel wrote:
> Please note that when I said I noticed a suspected variation in 
> pressure, I was referring to the difference between my reading and the 
> analysis, not a variation in pressure. I know there is a daily 
> fluctuation in pressure. Presumably it should be the same for everyone 
> in the vicinity.
>
> Also, just because a sensor is indoors doesn't mean that it's immune 
> to temperature variations. Such a notion presumes indoor temperature 
> is constant. Over the past 6 months or so my indoor temperature has 
> varied from about 46 to 86. I allow indoor temperature to vary for 
> economical reasons.
>
> Anyway, I haven't confirmed the effect I described. It might not even 
> be there. What I seem to notice, though, is that my readings are more 
> likely to be lower than the analysis during warm weather than during 
> cold weather. The difference is slight, since my QC tends to hover 
> between 98% and 100% for barometer.

From w4ake at att.net  Sun Jun  1 16:43:08 2008
From: w4ake at att.net (w4ake at att.net)
Date: Sun, 01 Jun 2008 21:43:08 +0000
Subject: [wxqc] rotate.aprs.net
In-Reply-To: <4842CD17.7070101@tamu.edu>
References: <f836cce7705b.4838ceae@optonline.net> <483967FA.3070309@tamu.edu>
	<052620080206.24340.483A1B320001609600005F1422243651029B0A02D29B9B0EBF0A050ECB99@att.net>
	<4842CD17.7070101@tamu.edu>
Message-ID: <060120082143.23622.484317EB000A90EC00005C4622230682229B0A02D29B9B0EBF0A050ECB99@att.net>

Hi Gerry ; Roger on your doings with rotate.aprs.net. Will let you know when I see erratic flow. As you have had contact with Davis WeatherlinkIP I hope they find a way to add the Hams verification numbers to the packets they send to rotate.aprs.net.when it becomes mandatory or we won't be able use rotate.aprs.net. with IP .I have been using IP for two months now and its great not to have a computer in the loop 24/7 .Also I hope they can add gusts & 24hr rain to the packets in the future as lack