Topic: Tipping spoon (new type) - adjusting

[TMThomson]

Mattk,

I have compared my readings against a 4" standard CoCoRaHS gauge mounted at the same level within less than 2 feet of the VP2 - which is what Davis support said I should be doing - and the VP2 was reading 43% higher than the manual gauge. They said I could make the adjustments described earlier in this thread, but to make 1/4 turn at a time. It would seem to me that the calibration is off on the VP2. Seems pretty straight forward to me. How else would you explain the variance? Miss-calibration? Or are we just playing a semantics game which I have no time for?

[WheatonRon]

I believe the design of the Davis spoon tipper is fundamentally flawed. It consistently over reports rainfall. The guidance Davis gave you to put the VP2 in close proximity to a CoCoRaHS gauge for comparison purposes is spot on. I am surprised they gave you guidance on how to calibrate their gauge—that is contrary to what they told me—that said, a calibration closer to reality makes a lot of sense—just not very accurate. Also, you cannot calibrate the spoon tipper directly with a CoCo gauge since the catch diameter is significantly different than the VP2 unless you wait for actual rainfall!

It has been about 5 years since Davis introduced the spoon tipper. I am surprised Davis hasn’t come up with a better mouse trap, so to speak, to address the design flaws in its spoon tipper.

[TMThomson]

WheatonRon,

Thanks for your insight. Makes more sense than what Mattk was talking about. Davis recommended making the small adjustments and see what 2 or three rainfalls looked like in comparison to the 4” gauge. Then make more adjustments accordingly. It’s almost as if they are acknowledging a problem. Somebody should go after them with a class action lawsuit for deceptive practices. Plus or minus 3% is a joke!

[Mattk]

Mattk,

I have compared my readings against a 4" standard CoCoRaHS gauge mounted at the same level within less than 2 feet of the VP2 - which is what Davis support said I should be doing - and the VP2 was reading 43% higher than the manual gauge. They said I could make the adjustments described earlier in this thread, but to make 1/4 turn at a time. It would seem to me that the calibration is off on the VP2. Seems pretty straight forward to me. How else would you explain the variance? Miss-calibration? Or are we just playing a semantics game which I have no time for?

Honestly you are really no understanding (or maybe wanting to understand) the principles involved here. Comparing any rain gauge to another rain gauge could indicate an issue but doesn't isolate what the issue is. Apparently you have convinced yourself before the facts and quite happy to attack something that just may not be the issue! Why? because you haven't proved what the actual issue is.

What you haven't provided at all are any of your actual numbers, just a % which is meaningless and doesn't really tell anybody anything, comparative wise. The VP2 tipper was notoriously inaccurate and always measured under and quite a lot under, this was in stark contrast to the original rain collector which was quite good and used on the Weather Monitor II.

You asked for advise but obviously don't have the time to provide the actual data or any meaningful discussion you are basing your assumptions on. Thankfully this is not my problem and unfortunately you actually do not know what the issue really is simply because you haven't checked the basic raw data functionality. 

[Mattk]

WheatonRon,

Thanks for your insight. Makes more sense than what Mattk was talking about. Davis recommended making the small adjustments and see what 2 or three rainfalls looked like in comparison to the 4” gauge. Then make more adjustments accordingly. It’s almost as if they are acknowledging a problem. Somebody should go after them with a class action lawsuit for deceptive practices. Plus or minus 3% is a joke!

When you actually run a calibrator over that gauge and have some actual factual numbers one can guarantee then you don;t have an argument to justify.

[Mattk]

.... It has been about 5 years since Davis introduced the spoon tipper. I am surprised Davis hasn’t come up with a better mouse trap, so to speak, to address the design flaws in spoon tipper.

The Davis VP2 Tipping spoon is actually a follow on from the Vantage Vue and that's been a tad more than 5 years.

[TMThomson]

I see a huge variance from a known accurate manual 4” gauge - which tracks perfectly with a standard 8” NWS gauge. What more do I need to know than I’ve got a very inaccurate VP2 tipping spoon. Two different spoons with drastically different results. Sorry to be short with you but beginning to feel ripped off by Davis. I frankly put hard earned money down on a piece of equipment that I expected to be accurate. I don’t have time to get all analytical and fix something Davis damn well knows is broken.

[CW2274]

http://cdn.thinglink.me/api/image/698016950395076608/1024/10/scaletowidth/0/0/1/1/false/true?wait=true

[WheatonRon]

WheatonRon,

Thanks for your insight. Makes more sense than what Mattk was talking about. Davis recommended making the small adjustments and see what 2 or three rainfalls looked like in comparison to the 4” gauge. Then make more adjustments accordingly. It’s almost as if they are acknowledging a problem. Somebody should go after them with a class action lawsuit for deceptive practices. Plus or minus 3% is a joke!

I think Davis in good faith released the spoon tipper but something went wrong. My guess is the spoon accumulates dirt and debris which adds “artificial rain” to the measurement but that is strictly a guess. Over the years, Davis has produced some great products—and supports them—so suggesting a “class action lawsuit” is a bit over the top. But releasing a better and new “tipper” at a discounted price for existing users, would be desirable and add a lot of PR to its consumer base, like you and me.

[TMThomson]

Perhaps a bit over the top, but it seems since their new ownership, quality and reliability overall has been slipping. (The posts on this forum prove that) There seems to be absolutely zero interest in admitting there is a problem. Time for a big wake up call at Davis. Time for them to stop resting on the laurels of their previous reputation and start putting quality and reliability back at the forefront of what they do.

[Mapantz]

The spoon tipper (all 3 that I had) was awful during heavy rain. It was evident from some of the rainfall rates I used to record- they were ridiculous, and didn't match up with radar dBZ.

The see-saw tipper still trumps their newer version. Far more consistent with all of my other means of rainfall recording.

There's no refuting that the newer spoon tipper is awful.

[TMThomson]

Mapantz,

Are the old tippers still available? If so, I would be interested in trying one.

[johnd]

The see-saw tipper still trumps their newer version. Far more consistent with all of my other means of rainfall recording.

There's no refuting that the newer spoon tipper is awful.

That is very much a minority opinion. The great majority of users report that the new spoon is consistently better than the old seesaw.

[kobuki]

That is very much a minority opinion. The great majority of users report that the new spoon is consistently better than the old seesaw.

That's good to hear, however I'm a bit curious since people whose stuff subjectively "just works" rarely report in for anything but a faint brag, and that's also rare. Some representative stats would be handy.

[Mapantz]

That is very much a minority opinion. The great majority of users report that the new spoon is consistently better than the old seesaw.

I haven't seen any positive feedback on it..

Another forum I frequent, has had several users complaining about the same thing. I had 3 that were reporting wild totals and rain rates. There's a clear issue with it! Davis don't give a monkey's about it, despite how many emails I have sent them about it.

[Mapantz]

That's good to hear, however I'm a bit curious since people whose stuff subjectively "just works" rarely report in for anything but a faint brag, and that's also rare. Some representative stats would be handy.

Part of the problem, is that if it has the Davis logo on it, it must always be correct and that nothing is wrong.

[TMThomson]

That seems to be the argument that I was getting from another user last night - never saw one that wasn’t within 4%. Unbelievable.

[kobuki]

Part of the problem, is that if it has the Davis logo on it, it must always be correct and that nothing is wrong.

No, that's Apple.
/offtopic
/sarcasm

[TMThomson]

 

[ocala]

If you go to this thread  https://www.wxforum.net/index.php?topic=39042.0  I successfully mounted a Rainwise tipper on my Davis base.
The RW is much better in terms of accuracy in my opinion, and I'm sure others who use it would chime in.
My only issue is that my ISS is way past it's it's prime so I have had connection issues related to water getting inside.
Other then that the RW is the way to go.

[PaulMy]

My experience with the tipping spoon is better than with the tipping buckets.

Recently I made a comparison between the VP2 tipping spoon (2 years old) and data to WLPC and WL.com compared to my CoCoRaHS (I have 2). 
I don't submit both CoCoRaHS readings, just the higher one, and there can be 0.2 mm difference between them due to locations. 

The VP2 is logged on a calendar day basis but I keep a manual record on the 24-hour 8:00 to 8:00 am reading, which is also my CoCoRaHS submission time.  Most often the VP2 tipping spoon is the same as CoCoRaHS, at least one if not both.  In the 20 days period we had 8 days with rain for a total of 58.2 mm recorded in the VP2 and 57.0 mm reading from the CoCoRaHS.  I am happy with the comparison as the 2.1% difference can be due to location of the 3 devices - about 25 feet difference to each other.

Enjoy,
Paul

[TMThomson]

Paul, I would be happy if I could get readings within 10% or less. It would surely be better than 43%!

[CW2274]

Other then that the RW is the way to go.

I already suggested this, but it fell on deaf ears. Keep  ....

[johnd]

The typical reasons for reported rainfall inaccuracy are eg:

• Some error in setting the correct rainfall increment somewhere in the software/settings
• Using a reference gauge which is in a different location or especially at a different height to the Davis gauge. The two gauges should have their openings at the same height and ideally be almost touching
• Trying to make a comparison using a single rainfall event that is very small (eg <1mm) or unusually intense
• If using a drip or pour test then not following the recommended procedure, eg pouring too quickly
• Having a partially blocked gauge
• Having reception issues with a wireless station whereby some of the rainfall is missed

And yes, very occasionally there may be a faulty spoon mechanism, but this can be easily replaced with new, usually free if within warranty and you can show that the above points have all been checked out and there is still a real problem.

[Sylver19]

Bonjour ,

Ici en France le mono auget métrique  ,je le calibre à 4.05 ml pour 0.2 mm , j'ai testé un mono auget inch , je le calibre à 3.9 ml pour 0.254 mm (convertit de 0.01 inch)