Just want to update on this one, there was talk about its performance in heavy rain, well
before the modification to 0.1mm was 228mm and its just broke that now at 374.4mm/hour
Bashy, Thats impressive. We have had very little rain here since I modified mine. I probably won’t see anything like that till early spring. So far though, it HAS recorded a couple of light sprinkles that it would have totally missed before it was modified. 
I m8 it aint bad, I was just thinking tonight (just before it happened) if it was perhaps
too big and missing tips (being overwhelmed as folks have pointed out, the reason i was
thinking this was because the recorded stuck from January till tonight, so i was getting
a tad worried, but its now put my mind at rest, well im chuffed with it for sure 
That’s effectively ~3.7 x the ‘max’ rate for the unit (i.e. the console would think of it as 3744mm/hour). I quietly hoped that the 999 limit just really mean “it can only show 3 digits”, maybe that’s the case. :lol:
One thing I have noticed here is that my 8" funnel / 0.25mm tip modified WMR928 gauge seems to suffer more ‘wind loss’ than the unmodified WMR200, i.e. on calmer or low wind days days they report very similar rain, but when it gets windy the 928 lags behind.
I’m thinking of trying out some ‘wind calming’ measures around the gauges…
Thats strange, you would have thought the bigger the area then more chance to catch the rain
but then i suppose thats counteracted by the tip offset, i should shut now as i dont really
understand what im on about, im just guessing lol
Sadly the console done have a memory for the rain rate 
but it aint shown any — tonight thats
for sure and i certainly dont remeber seeing anything in the 100’s either, perhaps a little baffling lol
Its only at 31mm/hr at present, WD is at 7.80 mm/hour
Hold on, you sure you didnt get it the wrong way round?
The strangest thing is its now dropped to 372.0mm/hour lol How is that possible?
I assumed you meant 374.4mm/hr as recorded in WD, which the console would (if it could) see as 3744mm/hr (because the console thinks that every tip represents a mm, whereas WD has been told that it’s only 0.1mm).
Or did you mean something else?
Strange.
Just to be sure - is this “Maximum rain rate” on the main WD screen we are talking about, or “All time records”, or both?
Its just my maths is all, never been any good at it lol but this is what i worked it out at;
to get 374 in WD would be 374 x 0.104 = 38.896mm on the console but like i said my maths
are totally pants, when it comes to decimals “i am NOT smarter than a 10 year old” lol
But yes WD all time record said 374.4 mm/hour but now it only says 372.0 mm/hour, surely this
is an impossibility? how can the maximum all time be recorded as 372 when an hour or so it was
374.4??
BOTH
Other way around.
The console knows nothing about the funnel, so it still thinks that every tip is 1mm.
WD knows that each tip is really 0.104mm
So the console thinks there is (approx) 10 times more rain than there really is.
Does that make sense?
No idea… :?
Yeah that makes more sense lol, told you i was a thicket pmsl…
Baffling on the all time record though, another gremlin me thinks?
You can’t calculate the funnel diameter for a particular tip size without referencing the original tip size in the calculation.
The math is incorrect:
For a 0.1mm tip resolution(ROC) your Funnel Size(MFS) would be: = 1000 mm (100cm funnel diameter)
For a 0.2mm tip resolution(ROC) your Funnel Size(MFS) would be:
= 500 mm (50 cm funnel diameter)
The tip size depends on the area of the funnel, not the diameter. If the diameter is halved, the area is reduced to one quarter of the original area / or the tip size increased to four times the original.
Hmmm … now what on earth was I thinking there?
Must be the late nights that got to me.
Any case here is the corrected version (I’ve deleted the old).
I think a good starting point for determining the funnel size for your rain gauge would be to first look up your all-time recorded [b]mm/h Rain Rate[/b]. Then you can calculate your max [b]bucket/funnel size[/b] as follows:
[b]ASSUMPTIONS (WMR200):[/b] `[b][color=red]RGR[/color][/b] = 999 mm/h ... rain gauge max resolution =
Better
But:
For a 0.1mm tip resolution(ROC) your Funnel Size(MFS) would be: MFS = RGD / sqrt(ROC) = 100 / sqrt(0.1) = 100 / 0.3162278 = 316.23 mm
That’s only valid if the original tip size is 1mm.
Or you could just use my online calculator.
Isn’t the tip(per) size (tipper quantity) irrelevant?
If I double the surface area on the rain gauge then sure I get double the water pouring through the funnel.
In other words it’ll tip twice instead of once for the same rain rate.
if 1mm of rain falls over a surface area of 100mm2 that would be: 1001 = 100ml
if 1mm of rain falls over a surface area of 200mm2 that would be: 2001 = 200ml
So I would have to adjust the WD resolution to 0.5 i.e. for every tip only count half the quantity.
That’s how I understand it from the WD setup below:
So if my tipper catches 2ml per tip and I double the surface area on the rain guage
the tipper is catching double the amount of water i.e. it will tip twice: 22ml = 4ml.
Therefore WD must only record half of it (4ml0.5 = 2ml).
Am I missing something here?
By the way I did some tipping on my rain guage (WMR200) and I’m get conflicting reports from the console, the WMR gatherer and WD logs.
`------------ ----- ----- ----- -----
Time of tip> 14h30 15h16 17h30 TOTAL
WMR Console 1.1mm 1.0mm 1.1mm 3.2mm
WMR Gatherer 9.7 10.8 11.8 ?
WD Log 1.3mm 1.1mm 1.0mm 3.4mm`
The previous record in the log on the 4Feb2009 @ 16h55 recoded 0.7mm.
No other rain for the day. I also see some tips of 0.8mm in the logs.
Now I wonder what my tip size is.
Is WD making it’s own rain or did I mess up a configuration somewhere.
The relationship is correct, if you increase the area 10x, you will reduce the tip to 1/10 of the original value - no argument there. But what you are missing is that you would only end up with a 0.1 mm tip, if you start with a gauge with a 1 mm tip and different brands and models of gauges have different tip sizes. If you 10x’d the area of a standard Davis gauge (which I wouldn’r recommend) you would end up with a 0.001 inch tip for instance.
Aha, I get it
If your tip size is 2ml and you want to bring it down to 0.5ml per tip then it would be 4x more accurate.
Which means a correction of 0.25 in WD.
Do you really get inaccurate rain gauges like that?
Hi guys, i have had to add a new funnel @ 280mm diameter i think i got the correct setting for WD but could someone
please confirm it is 0.032 please cause i aint sure if it is recording the rain correctly?
Or is it 0.128 ?
According to my calculations, the new setting in WD will be 0.128 mm for a funnel of diameter 280mm.
I use the calculations:-
OSI Rain Gauge I/D = 100mm Area = 7853.981 mm2
New funnel I/D = 280mm Area = 61575.216 mm2
Area increase = 7.84 (New funnel area / original area)
Rain gauge original tip = 1 mm
So new tip = 0.12755102 mm (original tip / area increase)
Hope it helps,
Ian
I agree