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...... This makes me wonder about the "official" measurement instruments at, eg, the National Weather Service, The Met, and similar agencies elsewhere. Are they subject to similar errors? How do they correct for them? Or do they? Surely they do, we think, but do they really, and how do they do it?

All tipping bucket type rain instruments (official or otherwise) are not exempt based on design from variable readings being related to variable rain rates which could be why high end systems also collect/store the water coming through the tippers which can provide further analysis and comparison to the electronic amount 
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I have a Davis VP2, my fourth Davis weather station over about 20 years. Let me stipulate at the outset that I am not an atmospheric scientist, physicist, meteorologist, or otherwise credentialed person in meteorology or almost anything else STEM. Let me also stipulate that my instrument siting is less than ideal, at least as measured against specifications by the WMO, for instance. No doubt many of us amateurs are in the same boat.

Recently I changed out my Davis VP2 tipping bucket rain sensor for the newer tipping spoon sensor. It had seemed to me generally, if not every time (oddly), that the Davis tipping buckets under-reported by c 20-30% what I collected in the standard 4" plastic rain gauge we use for the CoCoRaHS project, and which I view as authoritative: no moving parts, no electronics, an none of the associated errors. The tipping spoon in my recent experience has been more accurate than the buckets, ie, more aligned with the plastic gauge. But in a recent very heavy rain, the 4" gauge collected 3.40 inches, while the tipping spoon measured 2.38 inches, significantly less. Others in this thread report the opposite, that the tipping spoon has over-reported heavy rain.

It's unsettling to find reliable reports of substantially different tipping bucket or tipping spoon rain measurements in similar conditions. Presumably factory settings are consistent; it would make sense if discrepancies as measured against some standard (the 4" plastic gauge) were consistent too. They seem not to be.

We also recognize, as the instructions for my NovaLynx rain gauge calibrator advises, that a "rain gauge can only be calibrated to one rainfall rate at a time, and accuracy falls off above and below that rain because of the systematic error." "Tipping bucket rain gauges," the NovaLynx people say, and presumably tipping spoon rain gauges as well, "are subject to a systematic mechanical error which is a function of rain intensity . . . the error is non-linear, so a calibration curve is sometimes used to correct the data."

So there are two issues, one Davis might solve by stating to what rain intensity their gauges are calibrated, calculating the error to which their gauges above and below that intensity are subject, and providing a way to correct for the error. Ideally, Weatherlink would show an "absolute" rain amount as measured by the sensor, but also a "corrected" rain amount number based on compensatory software in the Weatherlink. I don't know what to do about the other issue, that some report the same mechanism, buckets or spoon, variously over-reports or under-reports similar conditions.

This makes me wonder about the "official" measurement instruments at, eg, the National Weather Service, The Met, and similar agencies elsewhere. Are they subject to similar errors? How do they correct for them? Or do they? Surely they do, we think, but do they really, and how do they do it?
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Hi Vincent,
It is on Android v 7.1.1
The install never gets past Installing.


Works fine on Samsung Galaxy S7


Can the Air Quality be shown from my Weatherlink.com AirLink?


Enjoy,
Paul

AirLink will be supported in a future release.
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Tried it but not getting temp data. Under weather stations it shows my station.
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Hi Vincent,
It is on Android v 7.1.1
The install never gets past Installing.


Works fine on Samsung Galaxy S7


Can the Air Quality be shown from my Weatherlink.com AirLink?


Enjoy,
Paul
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Installed it, set it up but I don't get any temperature or trends at the top. Refreshed the page and waited but still no temp. All the other stats are correct. I had the Weatherlink.com page in another tab and all the data is the same but no temp.

I will have a look at this tomorrow and fix that. Support is still new and it needs some fine tuning.

Best regards,
Vincent
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Installed it, set it up but I don't get any temperature or trends at the top. Refreshed the page and waited about 5 mins. but still no temp. Tried closing the app and starting it back up and no change.  All the other stats are correct. I had the Weatherlink.com page in another tab and all the data is the same but no temp.

Update... Closed it while I wrote this. Decided to open it one more time and now temp is showing. Guess I needed to wait longer. Odd that all other stats were there except temp.
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Davis says the adjustment is non-linear so they don't recommend it.
Any comments?

Non-linear, Correct. Also any calibration of the spoon design does not meet any sort of proper calibration procedure. Having to remove a device, pull it apart, adjust it (supposedly), put back together then reinstall just doesn't meet a proper calibration practice
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Hi Vincent,
Very nice [tup]


I was able to get it quickly installed on my Samsung phone.  However it does not seem to want to install on my Samsung Galaxy Tab E.
Like the quick selection of my station and then the local METAR.


Enjoy,
Paul

Thanks Paul. That's weird that you cannot install the app on your tablet. Which version of Android is it? It should work on Android version 5.1 and above.

If you have suggestions to enhance the app, feel free to send me a message.

Kind regards,
Vincent
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Davis says the adjustment is non-linear so they don't recommend it.
Any comments?
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