Topic: VP2 tipping spoon raingauge?

[Mattk]

Oh no I can feel a precision v accuracy headache coming on 

No kidding....the statement makes zero sense.
 
"Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip"

Did someone at Davis really say that??

So called consistency being off is not considered accurate. You have obviously not been reading the comments then?

And they have said that for the past 20 years (factory calibrated) and with hindsight we now know they were not, well they might have thought they factory calibrated them but  actually in the real world we knew then they were not but some believed the PR blurb rather than the facts. 

[WheatonRon]

Oh no I can feel a precision v accuracy headache coming on 

No kidding....the statement makes zero sense.
 
"Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip"

Did someone at Davis really say that??

Yes, but they are probably talking about two separate gauges— one that measures in inches the other in millimeters. They sell both.

[WheatonRon]

More results during today’s fairly rainy period (over a 7 hour period that ended at 2:00pm CDT):

Station 1, VP2 old tipper     .29 [.53]
Station 2, VP2 old tipper.     .67 [.35]
Station 3, VP2 new tipper.   .68  [.79]

CoCo gauge         .84 [.73]

In short, VP2 using new tipper vs. old tipper still doesn’t match accuracy of CoCo gauge. Disappointing results to say the least. My new tipper (station 3) was installed in a 3 year old ISS that has a daytime fan; station 1 is my newest station (less than 1 year old) that has a 24 hour fan; and station 2 is 10 years old and also has a daytime fan. The fans should have no bearing on rainfall. All three VP2 stations and the CoCo gauge are located at approximately the same height off the ground and within 50 feet of each other. Wind was not significant during this 7 hour period. All equipment was cleaned last week of dirt and debris.

In summary, disappointing results—maybe the new patent, if ever used by Davis, will improve these results.

We had a new rain event (8 hours) today.  The measurements I got today are posted adjacent to my prior numbers quoted above, except the latest ones are noted in brackets []. The new tipper VP2 (station 3) was moved to be right next to the CoCo gauge, probably less than 10 inches away. This time it over reported what the CoCo gauge did but was considerably closer to the VP2s that have the old tipper. While I wasn’t home the entire time, the rain I saw was steady but not a downpour with minimal wind.

In short, a lot a variability to say the least. More rain in the next few days and I will post additional updates to help clarify (muddy) the waters, pun intended.

[CW2274]

Oh no I can feel a precision v accuracy headache coming on 

No kidding....the statement makes zero sense.
 
"Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip"

Did someone at Davis really say that??

So called consistency being off is not considered accurate. You have obviously not been reading the comments then?

And they have said that for the past 20 years (factory calibrated) and with hindsight we now know they were not, well they might have thought they factory calibrated them but  actually in the real world we knew then they were not but some believed the PR blurb rather than the facts.

I have no idea what you're talking about. If you think I'm arguing with you, I'm not, I'm agreeing (or so I thought) that 0.01" is not a calibration number, but a resolution or precision number. Whatever % is an accuracy number. As far as them saying that for 20 years, guess I missed it.

[Mattk]

Oh no I can feel a precision v accuracy headache coming on 

No kidding....the statement makes zero sense.
 
"Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip"

Did someone at Davis really say that??

So called consistency being off is not considered accurate. You have obviously not been reading the comments then?

And they have said that for the past 20 years (factory calibrated) and with hindsight we now know they were not, well they might have thought they factory calibrated them but  actually in the real world we knew then they were not but some believed the PR blurb rather than the facts.

I have no idea what you're talking about. If you think I'm arguing with you, I'm not, I'm agreeing (or so I thought) that 0.01" is not a calibration number, but a resolution or precision number. Whatever % is an accuracy number. As far as them saying that for 20 years, guess I missed it.

...Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip...

Your words, not mine, so it's not a factory calibration now it is some form of resolution or precision number  So they have either factory calibrated the tipping spoons or they haven't, can't have it both ways.

And if it's not a calibration then all the comparisons are a waste of time until these tipping spoons have been calibrated. There can be no argument about this?   

[CW2274]

Oh no I can feel a precision v accuracy headache coming on 

No kidding....the statement makes zero sense.
 
"Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip"

Did someone at Davis really say that??

So called consistency being off is not considered accurate. You have obviously not been reading the comments then?

And they have said that for the past 20 years (factory calibrated) and with hindsight we now know they were not, well they might have thought they factory calibrated them but  actually in the real world we knew then they were not but some believed the PR blurb rather than the facts.

I have no idea what you're talking about. If you think I'm arguing with you, I'm not, I'm agreeing (or so I thought) that 0.01" is not a calibration number, but a resolution or precision number. Whatever % is an accuracy number. As far as them saying that for 20 years, guess I missed it.

...Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip...

Your words, not mine, so it's not a factory calibration now it is some form of resolution or precision number  So they have either factory calibrated the tipping spoons or they haven't, can't have it both ways.

And if it's not a calibration then all the comparisons are a waste of time until these tipping spoons have been calibrated. There can be no argument about this?

JC, talking to you is like talking to a brick wall. No they're NOT my words, they came from Ron above, who stated they came directly from Davis. All I'm saying is that 0.01" is NOT an accuracy number, it's the resolution that the rain is measured to. A percentage would be an accuracy number, which the statement DOES NOT include. The statement is very poorly worded, it should have said what percentage it's accurate to, which it doesn't, then stated at what resolution, which it does.
I guess this is all moot anyway as Davis is obviously lying through their teeth, so who cares......

[Mattk]

Oh no I can feel a precision v accuracy headache coming on 

No kidding....the statement makes zero sense.
 
"Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip"

Did someone at Davis really say that??

So called consistency being off is not considered accurate. You have obviously not been reading the comments then?

And they have said that for the past 20 years (factory calibrated) and with hindsight we now know they were not, well they might have thought they factory calibrated them but  actually in the real world we knew then they were not but some believed the PR blurb rather than the facts.

I have no idea what you're talking about. If you think I'm arguing with you, I'm not, I'm agreeing (or so I thought) that 0.01" is not a calibration number, but a resolution or precision number. Whatever % is an accuracy number. As far as them saying that for 20 years, guess I missed it.

...Please note that all new Vantage Pro2 rain collectors with a tipping spoon will be factory calibrated to either 0.01” or 0.2 mm per tip...

Your words, not mine, so it's not a factory calibration now it is some form of resolution or precision number  So they have either factory calibrated the tipping spoons or they haven't, can't have it both ways.

And if it's not a calibration then all the comparisons are a waste of time until these tipping spoons have been calibrated. There can be no argument about this?

JC, talking to you is like talking to a brick wall. No they're NOT my words, they came from Ron above, who stated they came directly from Davis. All I'm saying is that 0.01" is NOT an accuracy number, it's the resolution that the rain is measured to. A percentage would be an accuracy number, which the statement DOES NOT include. The statement is very poorly worded, it should have said what percentage it's accurate to, which it doesn't, then stated at what resolution, which it does.
I guess this is all moot anyway as Davis is obviously lying through their teeth, so who cares......

And obviously not many understand calibration in any meaningful or useful way but hey just keep on trucking and keep those excuses coming, it appears not many understand what Davis state at all 

[SnowHiker]

We had a new rain event (8 hours) today.  The measurements I got today are posted adjacent to my prior numbers quoted above, except the latest ones are noted in brackets []. The new tipper VP2 (station 3) was moved to be right next to the CoCo gauge, probably less than 10 inches away. This time it over reported what the CoCo gauge did but was considerably closer to the VP2s that have the old tipper. While I wasn’t home the entire time, the rain I saw was steady but not a downpour with minimal wind.

In short, a lot a variability to say the least. More rain in the next few days and I will post additional updates to help clarify (muddy) the waters, pun intended.

Thanks for the updates.  Your experience and the experiences of others are useful for those who may be interested in "upgrading". 

Hopefully the usefulness of this thread doesn't get buried in the quibbling over the meaning of words, misunderstandings of how they're used, and other nonsense.

[CW2274]

We had a new rain event (8 hours) today.  The measurements I got today are posted adjacent to my prior numbers quoted above, except the latest ones are noted in brackets []. The new tipper VP2 (station 3) was moved to be right next to the CoCo gauge, probably less than 10 inches away. This time it over reported what the CoCo gauge did but was considerably closer to the VP2s that have the old tipper. While I wasn’t home the entire time, the rain I saw was steady but not a downpour with minimal wind.

In short, a lot a variability to say the least. More rain in the next few days and I will post additional updates to help clarify (muddy) the waters, pun intended.

Hopefully the usefulness of this thread doesn't get buried in the quibbling over the meaning of words, misunderstandings of how they're used, and other nonsense.

I have absolutely no proof one way or another, but I don't consider it nonsensical that the talk here is that Davis is basically being accused of fraud by claiming that their rain tipping buckets are indeed calibrated to published spec, if at all.

[WheatonRon]

More results during today’s fairly rainy period (over a 7 hour period that ended at 2:00pm CDT):

Station 1, VP2 old tipper     .29 [.53]  {1.64}  FW3075
Station 2, VP2 old tipper.     .67 [.35]  {1.26}  FW4350
Station 3, VP2 new tipper.   .68  [.79]  {2.60}  CW5020

CoCo gauge         .84 [.73]  {2.48}

In short, VP2 using new tipper vs. old tipper still doesn’t match accuracy of CoCo gauge. Disappointing results to say the least. My new tipper (station 3) was installed in a 3 year old ISS that has a daytime fan; station 1 is my newest station (less than 1 year old) that has a 24 hour fan; and station 2 is 10 years old and also has a daytime fan. The fans should have no bearing on rainfall. All three VP2 stations and the CoCo gauge are located at approximately the same height off the ground and within 50 feet of each other. Wind was not significant during this 7 hour period. All equipment was cleaned last week of dirt and debris.

In summary, disappointing results—maybe the new patent, if ever used by Davis, will improve these results.

We had a new rain event (8 hours) today.  The measurements I got today are posted adjacent to my prior numbers quoted above, except the latest ones are noted in brackets []. The new tipper VP2 (station 3) was moved to be right next to the CoCo gauge, probably less than 10 inches away. This time it over reported what the CoCo gauge did but was considerably closer to the VP2s that have the old tipper. While I wasn’t home the entire time, the rain I saw was steady but not a downpour with minimal wind.

In short, a lot a variability to say the least. More rain in the next few days and I will post additional updates to help clarify (muddy) the waters, pun intended.

More rain. For the 24 hours ended 7am on May 1 (includes the 8 hour period previously posted), the new numbers are noted in squiggly brackets, that is—{ and }. It appears the new spoon tipper is achieving better accuracy during heavy rains, which is good.  My anemometer (common to all three VP2s) never exceeded a gust of 12 mph and for the most part winds apparently were not a factor.

Based on this storm, it appears the new spoon tipper achieves better accuracy in heavy rains than the old tipper. Worth another $50? Maybe.

[galfert]

All this testing is great. I think most results coming in are positive. And the question we all want to know is how much better is it. That is proving to be a bit difficult to answer because of ambiguity of Davis calibration definition, and perhaps it is too soon with not enough comparisons, and most importantly Davis has not released documentation nor product specifications.

That said though, wouldn't you think that Davis came out with this new gauge for a good reason? I'm sure Davis tested and came out with this new rain gauge to solve some problems. It would need to be the same or better performing than the old version. The same performance would still make sense if it affected some manufacturing cost savings, or manufacturing assembly savings, or product longevity issue. Certainly I don't think it would make any sense for Davis to have put out an inferior performing replacement part as that would not go over well and it would hurt them in many ways. So for anyone experiencing inferior performance results perhaps your tests are not the best that they could be. Or maybe your particular rain event was not the typical type of rain event that Davis aimed for in improving. Maybe you just need to do more testing to get rid of outliers.

What a shocker it would be if Davis releases the specifications and they match exactly to the old version    eeek!

[johnd]

Personally, I wouldn't expect the specification to change with the tipping spoon gauge. The problem with the existing gauges has never been with the specification but that too many examples do not seem to meet the specifications.

And then the underlying problem is that it's very difficult to get a good fix on the accuracy of an individual gauge, which can only really be assessed - at least to scientific standards - at a site with good exposure, with due care to correct mounting of the gauge, a high quality reference gauge read reliably and readings taken over at least a month to account for variable rain rates and amounts, different wind strengths etc. Very few users have the facilities and dedication to achieve this, plus all too often reports of accuracy/inaccuracy are confounded by issues of mounting height, exposure, lack of a good reference gauge, failure to make the correct increment setting in console or software etc etc. In fact the only good report of VP2 accuracy I've ever seen was Stephen Burt's. Maybe others exist - it would be good to get some additional references.

[drew1021]

I spoke with a guy at Davis a few days ago and he informed me that the spoon assy's were laser calibrated to ensure the highest accuracy. I asked for specs on accuracy and was told that there were none published as of yet. I also asked about field testing and was told that there testing was done between 4" gauge and the new spoon assy. I would have thought that they would use 8" gauges for field testing. I don't trust what he said about the reference gauges used. That's all I have for now. Come on rain!

[CW2274]

Personally, I wouldn't expect the specification to change with the tipping spoon gauge.

I'm getting the same impression. However, the Davis pub sent to me last night, straight from the horse's mouth, "The tipping spoon is an incremental improvement for both accuracy and durability". Really? If so, what's the big secret? How much or what is the "incremental improvement." Perhaps as Ron stated, it handles the heavier events better. All I know is that if something is improved, that's generally not kept hush-hush, especially if they expect people to pony up for the new and "improved" version.

[johnd]

If so, what's the big secret?

http://pronamic.com/products/tipping-bucket-technology maybe gives some clues, though it is a different design. Most of it is pretty obvious and what you'd have guessed anyway, eg there's a fixed force acting as the counterbalance which is going to remain constant, just one single screw needed for calibration, no risk of imbalance developing between two buckets etc etc

Also re 'durability' AIUI the reed switch is now a cartridge type and user replaceable.

Much of the rest is just marketing fluff and I really wouldn't read too much into it. But if the tipping spoon can consistently achieve the existing Davis rain gauge specification then that would be a real step forwards.

[CW2274]

If so, what's the big secret?

But if the tipping spoon can consistently achieve the existing Davis rain gauge specification then that would be a real step forwards.

And I'm betting that's exactly what they're hanging their hat on.

[Mattk]

.... I spoke with a guy at Davis a few days ago and he informed me that the spoon assy's were laser calibrated to ensure the highest accuracy....

It does sound very highly technical doesn't it when the term laser calibrated is used, but what do they actually mean? Ask for an explanation and see how far you get Knowing how the "silver" tipping bucket was so called "laser calibrated" then they must be running this one on the help desk again

[Mattk]

.... And the question we all want to know is how much better is it. That is proving to be a bit difficult to answer because of ambiguity of Davis calibration definition, and perhaps it is too soon with not enough comparisons, and most importantly Davis has not released documentation nor product specifications.

Enough has probably been said about Davis calibration but all Davis can do is set a nominal adjustment and that adjustment was typically all very close but was just a long way off and it was always lower and again this had a bit to do with their so called "laser calibration" of the then new silver buckets which weren't within a bulls roar of the older, higher set tipping bucket which had totally different dynamics to the useless silver buckets.

Davis has had quite some experience now with the Vue and apart from some quirky things with the Vue spoon and for the size of the Vue it probably runs rings around the current VP2 gauge so one would be expecting improvement?   

[WheatonRon]

Another steady rain event for four hours this morning with very little wind—a perfect test so to speak. I moved another one of my VP2s next to the CoCo gauge with interesting results as follows:

CoCo gauge  .47
VP2 with new tipper located inches away from CoCo gauge .46
VP2 with old tipper located inches away from CoCo gauge  .36
VP2 with old tipper located about 50 feet away .41

Take aways. New tipper did very well when located next to CoCo gauge. Old tipper, even when located next to CoCo gauge showed mixed results. More testing is necessary but new spoon tipper shows promise—IF future results mirror these results.

Since April 27, 2019, I have recorded 5.75 inches of precipitation (CoCo measured) including 5 inches of heavy snow on April 27 at my suburban Chicago house! Folks, that is a lot of precipitation—but nearby Mallards are happy!

[drew1021]

So I go out to check my stratus gauge after an overnight light to moderate rain and right away I notice a -.03 discrepancy between the VP2 and the stratus. The VP2 being the lower of the two and the stratus showing.19.  Scratching my head I decided to remove the aero cone and check for obstructions. And what do I find, a tiny oak tree seed pod lodged in the bottom of the funnels hole. And yes I have the plastic filter installed. Lesson learned, be sure to check the cone for any obstructions before a rain event. We are expecting more rain throughout the day so hopefully I can report some more reliable results later on.

[Mattk]

One can have all the new beaut flash bang WiFi multi-app wizardry but if the data-in is craped then the data-out is craped and it's not like this rain cone tipper blockage is something new, it has been an inherent flaw in the design since day 1 and no amount of silly debris or clip in grate things will prevent this, the birds and the twigs win every time without some simple re-engineering .

Maybe the tipping spoon will reduce some of the twig issue but the bird poop is another issue   

[Gretnawx]

One can have all the new beaut flash bang WiFi multi-app wizardry but if the data-in is craped then the data-out is craped and it's not like this rain cone tipper blockage is something new, it has been an inherent flaw in the design since day 1 and no amount of silly debris or clip in grate things will prevent this, the birds and the twigs win every time without some simple re-engineering .

Maybe the tipping spoon will reduce some of the twig issue but the bird poop is another issue

I have not had bird droppings in my rain cone since using the bird spikes Davis came up with several years ago.  They have been standard on all rain cones for probably five years, have you tried them? 

[Gretnawx]

I've had the single spoon gauge installed for about a month and am pleased with it.  It has been within +/-.01" of my 8" NWS Coop gauge for each of the 10 rain events  since installation (ranging from .01" to .68"). We've had no really heavy rains to compare as yet.  Did not see consistency like that with the two-spoon tipper which typically read lower than the NWS gauge by several hundredths despite repeated attempts to calibrate it higher.   

[drew1021]

I've had the single spoon gauge installed for about a month and am pleased with it.  It has been within +/-.01" of my 8" NWS Coop gauge for each of the 10 rain events  since installation (ranging from .01" to .68"). We've had no really heavy rains to compare as yet.  Did not see consistency like that with the two-spoon tipper which typically read lower than the NWS gauge by several hundredths despite repeated attempts to calibrate it higher.

Glad to hear you've had good results with your 8" gauge. Just the kind of information I've been looking for. Have you done any comparisons between the 8" and the 4" stratus gauge?

[Gretnawx]

I've had the single spoon gauge installed for about a month and am pleased with it.  It has been within +/-.01" of my 8" NWS Coop gauge for each of the 10 rain events  since installation (ranging from .01" to .68"). We've had no really heavy rains to compare as yet.  Did not see consistency like that with the two-spoon tipper which typically read lower than the NWS gauge by several hundredths despite repeated attempts to calibrate it higher.

Glad to hear you've had good results with your 8" gauge. Just the kind of information I've been looking for. Have you done any comparisons between the 8" and the 4" stratus gauge?

I had a 4" gauge several years ago and it compared closely to 8" NWS gauge except in high winds when it read a little lower than the 8" gauge. Now I just have the VP2 single spoon and NWS gauges as shown in attached picture.