Topic: new VP2 rain gauge way off

[Jasiu]

A while back, I replaced the original tipping "see-saw" with this:

  https://www.davisinstruments.com/product/vantage-pro2-tipping-spoon-replacement-kit-inches/

We've been in a drought, so I haven't had much data to use to check on accuracy. Now, we've had a good 24 hours of semi-steady rain. My Coco manual gauge had exactly one inch while the VP2 reported 1.71", so something is quite awry. The Coco gauge is only two feet away from the VP2 with no aerial obstructions above to cause less rain to hit the manual gauge (and, yes, I know how to deal with greater than one inch in the manual gauge).

I'll do some investigation, but if there was something I needed to modify in the console or some calibration step I missed that is obvious, please let me know.

Thanks a lot!!

[Jasiu]

I should also note that I switched to the new "aero cone" collector on the VP2 also.

[PaulMy]

Hi Jasiu

I'll do some investigation, but if there was something I needed to modify in the console or some calibration step I missed that is obvious, please let me know.

If you find anything please post... I've got the metric replacement kit on the way.


Enjoy,
Paul

[92merc]

I bought one when they first came out.  Mine was plug and play.  I compared to my CoCoRahs style gauge for a couple of months and they were spot on.

Sorry, I'm not much help.  Mine worked out of the box.  Outside of verifying you are level, that's all I can think of.

[CW2274]

My Coco manual gauge had exactly one inch while the VP2 reported 1.71",

That's beyond ridiculous. Like 92merc says, you should have to do nothing. Are you positive you installed the new spoon assembly correctly? If so and you're still under warranty, I'd send it back. A 71% error is just a touch more than the claimed 4%.

[Jasiu]

FINALLY had another significant rainfall, and...

CoCo gauge: 1.95"
Davis gauge: 1.96"

So I must have seriously brain farted something that original time. Wouldn't be the first. 

If I see any big discrepancies in the future I'll let y'all know but for now I'm labeling this operator error.

[WheatonRon]

The spoon tipper is initially more accurate than the teeter totter version. However, you must the clean the spoon tipper more often otherwise, it will over report rain. What happens is “gunk” from birds, tree debris will land in the spoon adding weight therefore increasing tip frequency in a rain storm.  Such “gunk” in the teeter tooter version tends to fall out after each tip from rain—not so with the spoon. Bottom line? Keep your ladder handy and clean the spoon. The rest if the ISS could use a dusting or quasi-bath too.

[BrianLehan]

I noticed a few posts about the accuracy of the new style tipping-spoon verses the old style tipping-bucket and at some point my confidence eroded and I was convinced and worried that my readings were no longer accurate for the past year or so. 

To test I my theory and rebuild my confidence in my readings, I moved my "Acu>Rite" Magnifying manual gauge from the backyard and mounted it near my Davis rain collector. I then mentioned my suspicions to my buddy Ryan who lives a mile as the crow fly's from me. He has a Davis using the older tipping-bucket style, and he checks it against his CoCoRaHS gauge mounted nearby his rain collector. He is also our local on air Chief Meteorologist so has professional equipment at the station which forms a triangle about a mile from both our homes so we expected sample rainfalls within a narrow margin of error. Now all we needed was actual rain to measure.

Today we got some and confirmed our readings, all within a tenth or so of each other. 1.07 here in Davis, 1 and a hair on the manual. 1.04 at his place. So the tipping-spoon I installed out of the box with no adjustments physically, or in the software is 100% accurate.

Now while I can sleep at night knowing this, I can't guarantee that during installation - which I found as easy as the directions made it sounds - that someone could have changed factory calibration, or that they bought or received by mistake a Metric celebrated unit when they calculate in Inches and Vice Versa.  Not sure in the end that would make much of a difference since I think most software these days can be set to calibrate in one unit but display in another calculating the difference but not sure on that 100%.

I can't see any reason not to upgrade to the new style tipping-spoon, if your old style tipping-bucket, has kicked-the-bucket.     

[Bunty]

But there can be a lot of difference between your location and some other location a mile away.  It can be amazing how much the rain amounts can vary in my small town from one side to the other.

[Jasiu]

But there can be a lot of difference between your location and some other location a mile away.  It can be amazing how much the rain amounts can vary in my small town from one side to the other.

Or less than a half mile away! I got 1.60" yesterday (both VP2 and CoCo gauge) and friend's station I tend .4 mile away got 1.73".