Topic: Dealing with barometric pressure on Meteobridge via ObserverIP vs GW1000

[galfert]

Notice I didn't mention Relative Pressure in the previous post. That was on purpose. Your console's Relative Pressure is whatever you want it to be. It could be that you calibrated it to Sea Level Pressure or that you calibrated it to be Altimeter Pressure.

Here is the thing though. In order for the Meteobridge to calculate accurate Altimeter it needs your console (ObserverIP or GW1000) to have the proper real station pressure (Absolute Pressure). The Meteobridge needs this as a starting point. The Meteobridge does not care what your console says is Relative Pressure. The Meteobridge only uses your Absolute Pressure.

So if you set your proper elevation offset (done setting Relative Offset) and then you calibrate your station so that Relative Pressure matches local METAR Altimeter (done by raising or lowering Absolute Pressure offset), then your console's shown Relative Pressure will not match what gets uploaded by the Meteobridge to sites that expect Sea Level Pressure.

What I do is I calibrate my console's Relative Pressure (done by increasing or lowering Absolute Offset) so that Relative Pressure shown matches METAR Sea Level Pressure (not METAR Altimeter). If you use the Aviationweather.gov website you'll be able to get METAR Sea Level Pressure.
https://www.aviationweather.gov/metar/data?ids=KTIK&format=decoded&date=&hours=0
https://www.aviationweather.gov/metar/data?ids=KOKC&format=decoded&date=&hours=0
https://www.aviationweather.gov/metar/data?ids=KPWA&format=decoded&date=&hours=0

Doing this ensures the following:
- Both Meteobridge and Console will then agree on formula for what is shown on WU.

I think this is the crux of the problem of why you are having a hard time keeping the diffent consoles calibrated. At your elevation the average difference between Sea Level Pressure and Altimeter is about 1.0 hPa or 0.03 inHg.

[andyk1]

One other thing you should know about using the Meteobridge...

[uh..... dreading this  .... Here goes nothing... ]

The Meteobridge uploads Sea Level Pressure to most all weather services. The exception is CWOP which instead gets Altimeter Pressure uploaded.

The Meteobridge starts with Absolute Pressure (station pressure) and uses that to calculate both Sea Level Pressure and Altimeter Pressure. They are slightly different formulas and yeild slightly different results.

I'm only bringing this up because you cannot compare your Meteobridge's upload to Weather Underground with that of CWOP. Each is getting a different value on purpose. That is just the way it is. The Meteobridge is following what each service expects and what each of those services calls for in their upload requirements. That is not to say that some people do things to circumvent this.

So just know that while comparing your GW1000 pressure to your ObserverIP that you should be comparing Sea Level Pressure sites to each other and not use an Altimeter site as a comparison to a Sea Level site. I don't know what your personal website is being feed (Sea Level Pressure or Altimeter).

Am answering this post first and get back to your previous in a few minutes as it's quit detailed and requires thought.

I always use hpa Absolute Pressure Offset and not Relative Pressure Offset to calibrate both OIP and the GW1000.
   

[andyk1]

Notice I didn't mention Relative Pressure in the previous post. That was on purpose. Your console's Relative Pressure is whatever you want it to be. It could be that you calibrated it to Sea Level Pressure or that you calibrated it to be Altimeter Pressure.

We are on the same page. I always only ever calibrate the sea level pressure when needed. On the OIP it is usually never since it always dead on.

Here is the thing though. In order for the Meteobridge to calculate accurate Altimeter it needs your console (ObserverIP or GW1000) to have the proper real station pressure (Absolute Pressure). The Meteobridge needs this as a starting point. The Meteobridge does not care what your console says is Relative Pressure. The Meteobridge only uses your Absolute Pressure.

Switched OIP and gw1000 to hpa. Done and done. Can not get ws-2902 console to connect to my wifi. A none issue that still has not been resolved. will keep trying.

So if you set your proper elevation offset (done setting Relative Offset) and then you calibrate your station so that Relative Pressure matches local METAR Altimeter (done by raising or lowering Absolute Pressure offset), then your console's shown Relative Pressure will not match what gets uploaded by the Meteobridge to sites that expect Sea Level Pressure.

My relative offset is 43.7 hpa by your calculations yesterday which was dead on after researching it myself. Again thanks.

What I do is I calibrate my console's Relative Pressure (done by increasing or lowering Absolute Offset) so that Relative Pressure shown matches METAR Sea Level Pressure (not METAR Altimeter). If you use the Aviationweather.gov website you'll be able to get METAR Sea Level Pressure.
https://www.aviationweather.gov/metar/data?ids=KTIK&format=decoded&date=&hours=0
https://www.aviationweather.gov/metar/data?ids=KOKC&format=decoded&date=&hours=0
https://www.aviationweather.gov/metar/data?ids=KPWA&format=decoded&date=&hours=0

Doing this ensures the following:
- Both Meteobridge and Console will then agree on formula for what is shown on WU.

Again, We agree on just increasing or decreasing ABSOLUTE PRESSURE only

I think this is the crux of the problem of why you are having a hard time keeping the diffent consoles calibrated. At your elevation the average difference between Sea Level Pressure and Altimeter is about 1.0 hPa or 0.03 inHg.

Well they are both set to hpa now with a relative of 43.7 with a calibration on both OIP and gw1000 to match absolute which of course are different on each. For the OPI Absolute is set to -2.37 and gw1000 offset is -7 and both in hpa not inHg as you suggested. I am already seeing a drift of -.03 inHg in the gw1000 the past 7 degree(F) rise since I strarted so the pressure sensor in my gw1000 if off... meaning bad.

As I said before am waiting for the upgraded version to be released before I replace it. We are expected to get to 91 today so this should be a good test. I expect an error of .04 inHg in the gw1000. We'll see but I have been dealing with this for a while.

Thanks a bunch for your help and glad to see you are very informed on what you are saying and the help you offer others. My hats off to you.

Andy

[andyk1]

My console absoluely will not connect to my wifi with any methods I've used including the Ambient Tool Android app, WS View or amnet apps. Giving up for now.

[galfert]

Strange that your CWOP raw data still only shows pressure changes in 0.3 hPa increments if you've changed the ObserverIP to use hPa.

Maybe you have an older WH25B that does not work like the newer one I have. If you ever decide on getting a WS-2000 display just be sure to also get a WH32B instead of using that old WH25B.

Your GW1000 does show a bit of wonkyness. I don't know if that is because you've been messing with it or it's like you said it doesn't act right. It seems to get stuck is at times is what I'm seeing. Contact Lucy @ Ecowitt and see about getting a replacement. Seems like you are interested in the increased range so I guess you can wait for that.

Good job on following along. It is hard to give advice and support because it's difficult to gauge the level of comprehension of the individual. Makes it hard to know how much to dumb it down. If I seemed too repetitive or too basic for what you already knew I apologize. That is the hard part of helping others. Seems to me like you already had a good handle on things, but I had no way of knowing.

Realize too that I'm also learning from you. I'm learning about your hardware that is behaving differently than from my seemingly same hardware. Most curious to me is this WH25B difference. Did you restart the ObserverIP after switching to hPa? I seem to remember that it maybe was a requirement but I not certain now since it's bee a while.

[galfert]

One other thought....

Have you actually tested the Meteobridge with the GW1000? Or are you just looking at what the GW1000 does by itself? This could be a big difference. Realize that the Meteobridge doesn't not care about the ObserverIP Relative Pressure. I know I said that. But the important thing to realize is that the Meteobridge is calculating Relative from Absolute and the GW1000 by itself is doing the same thing and perhaps these methods differ. We know the GW1000 and the ObserverIP calculate Relative just by an Offset. Maybe the Meteobridge does this a different way. So if you test the GW1000 with the Meteobridge you may see different results than with the GW1000 alone.

One other thing you could test is the ObserverIP directly uploading to WU....to a 3rd WU ID for comparison. It would be interesting to see if the ObserverIP to WU matched the Meteobridge to WU (while using the ObserverIP for the Meteobridge).

[andyk1]

One other thought....

Have you actually tested the Meteobridge with the GW1000? Or are you just looking at what the GW1000 does by itself? This could be a big difference. Realize that the Meteobridge doesn't not care about the ObserverIP Relative Pressure. I know I said that. But the important thing to realize is that the Meteobridge is calculating Relative from Absolute and the GW1000 by itself is doing the same thing and perhaps these methods differ. We know the GW1000 and the ObserverIP calculate Relative just by an Offset. Maybe the Meteobridge does this a different way. So if you test the GW1000 with the Meteobridge you may see different results than with the GW1000 alone.

One other thing you could test is the ObserverIP directly uploading to WU....to a 3rd WU ID for comparison. It would be interesting to see if the ObserverIP to WU matched the Meteobridge to WU (while using the ObserverIP for the Meteobridge).

Yes it's acting weird. Jumping around at 2 hpa at very little temp changes and back to correct reading then off again.

Yes all is set to hpa now OIP and gw1000. Yes I have tried the gw1000 on the meteobridge with the same results. Bad unit or at least pressure sensor as everything else is working perfectly.

[andyk1]

No I haven't made any calibration changes to the gw1000 since I set both OIP and gw1000 to hpa at 81 degrees (F) It is now 94 degrees showing a .04 inHg drop lower on the gw1000.
It's maddening chasing numbers.

[andyk1]

Your are having an error on your humidity at https://weather.gladstonefamily.net/site/F3708 which is your CWOP station?

[galfert]

Your are having an error on your humidity at https://weather.gladstonefamily.net/site/F3708 which is your CWOP station?

Yes that is my CWOP. And no I'm not having a humidity problem. The thing to know about Gladstonefamily analysis is that the analysis is only as good as your neighbors' stations. In the past month 3 different Davis stations around me had their humidity sensor go out. They are offline now only because I notified them. One of them is a Davis Vue (no fix for that) and the other two are VP2 and they have ordered replacement sensors. But I'm stuck with the bad analysis but only for a month. The default view on Gladstonefamily.net is 1 month. But you can change the URL to any number of days you want. The easiest way is to use the links for Last 3 days, or Last 7 days, or Last 14 days. Once you do that you can easily customize the URL to any number of days you want.

From this URL you can see the past 20 days are good.
https://weather.gladstonefamily.net/site/F3708?days=20#Data

So I'm only 1 week away from having that red X go away from the default 1 month view.

When you see a red X in Gladstonefamily.net ...you should look at the neighboring stations to see who really has the problem.

[galfert]

One other thought....

Have you actually tested the Meteobridge with the GW1000? Or are you just looking at what the GW1000 does by itself? This could be a big difference. Realize that the Meteobridge doesn't not care about the ObserverIP Relative Pressure. I know I said that. But the important thing to realize is that the Meteobridge is calculating Relative from Absolute and the GW1000 by itself is doing the same thing and perhaps these methods differ. We know the GW1000 and the ObserverIP calculate Relative just by an Offset. Maybe the Meteobridge does this a different way. So if you test the GW1000 with the Meteobridge you may see different results than with the GW1000 alone.

One other thing you could test is the ObserverIP directly uploading to WU....to a 3rd WU ID for comparison. It would be interesting to see if the ObserverIP to WU matched the Meteobridge to WU (while using the ObserverIP for the Meteobridge).

Yes it's acting weird. Jumping around at 2 hpa at very little temp changes and back to correct reading then off again.

Yes all is set to hpa now OIP and gw1000. Yes I have tried the gw1000 on the meteobridge with the same results. Bad unit or at least pressure sensor as everything else is working perfectly.

Okay, I think that settles it. Bad GW1000.

[andyk1]

Your are having an error on your humidity at https://weather.gladstonefamily.net/site/F3708 which is your CWOP station?

Yes that is my CWOP. And no I'm not having a humidity problem. The thing to know about Gladstonefamily analysis is that the analysis is only as good as your neighbors' stations. In the past month 3 different Davis stations around me had their humidity sensor go out. They are offline now only because I notified them. One of them is a Davis Vue (no fix for that) and the other two are VP2 and they have ordered replacement sensors. But I'm stuck with the bad analysis but only for a month. The default view on Gladstonefamily.net is 1 month. But you can change the URL to any number of days you want. The easiest way is to use the links for Last 3 days, or Last 7 days, or Last 14 days. Once you do that you can easily customize the URL to any number of days you want.

From this URL you can see the past 20 days are good.
https://weather.gladstonefamily.net/site/F3708?days=20#Data

So I'm only 1 week away from having that red X go away from the default 1 month view.

When you see a red X in Gladstonefamily.net ...you should look at the neighboring stations to see who really has the problem.

Yeah the dreaded neighbors with bad setup and calibrations way off puts your station off kilter till they correct their errors and then takes 24 hours or longer to put you back on track. We've all been there. Why I don't put the gw1000 on meteobridge and only WU.

[andyk1]

One other thought....

Have you actually tested the Meteobridge with the GW1000? Or are you just looking at what the GW1000 does by itself? This could be a big difference. Realize that the Meteobridge doesn't not care about the ObserverIP Relative Pressure. I know I said that. But the important thing to realize is that the Meteobridge is calculating Relative from Absolute and the GW1000 by itself is doing the same thing and perhaps these methods differ. We know the GW1000 and the ObserverIP calculate Relative just by an Offset. Maybe the Meteobridge does this a different way. So if you test the GW1000 with the Meteobridge you may see different results than with the GW1000 alone.

One other thing you could test is the ObserverIP directly uploading to WU....to a 3rd WU ID for comparison. It would be interesting to see if the ObserverIP to WU matched the Meteobridge to WU (while using the ObserverIP for the Meteobridge).

Yes it's acting weird. Jumping around at 2 hpa at very little temp changes and back to correct reading then off again.

Yes all is set to hpa now OIP and gw1000. Yes I have tried the gw1000 on the meteobridge with the same results. Bad unit or at least pressure sensor as everything else is working perfectly.

Okay, I think that settles it. Bad GW1000.

Yeah I bit the bullet and ordered a new one off amazon just a few ago. should be here Tuesday. Maybe I'll get lucky and get the newer updated version but not holding my breath.