modify bucket to 0.1mm

Actually all those calculators are wrong, back to the drawing board :oops:

At the risk of causing more confusion…

In going from a 100mm diameter to a 200mm diameter you doubled the diameter.
If you multiply the diameter by 2 you change the collecting area by 2 x 2 = 4. So with 4 times the area each tip will be caused by 1/4 = 0.25 as much rain as with no modification.

If you increase the original 100mm to 310mm, you have increased the collecting area by 3.1 x 3.1 = 9.61. With 9.61 times the area each tip will be caused by 1/9.61 = 0.104 as much rain as with no modification.

Does that make sense?

Oh dear Niko pmsl… not to worry…

Hi skyewright, thanks for joining in :slight_smile:

To answer your question “Does that make sense?” not really cause my original is 113.5 :?

skyewright that’s exactly right :smiley: The calculators agree now too, sorry about that, never did a php calculator before :lol:

Couldn’t resist. :smiley:

Are you sure? I thought the inside diameter of an unmodified WMR928 rain gauge was 100mm.

Are you using something else?

I was going by what the book says, so that must be the outside diameter then?

That’s what that figure it sounds like to me.
Maybe you could do a rough check by holding a ruler against your gauge?
Not precise, but it should at least indicate which figure is more likely.

Not possible to measure it anymore the modifications prevent that :frowning:

I will go by your measurement of 0.104 that certainly sounds about right to me

Thanks for your help, you to Niko and you three Breitling, appreciated guys :slight_smile:

Yes, that’s exactly the math to do.

Thanks for the confirmation Breitling

At least i now have this bookmarked for future reference :slight_smile:

Hi all !
Very interresting topic !
I’m currently using a 0.43mm tip resolution with my wmr928nx.
Based on this discussion :
http://discourse.weather-watch.com/p/217209

Here’s my actual installation (i’m currently testing the accuracy of this assembly :slight_smile:

The funnel (15cm diameter)

Final assembly

Wish my mod was as clean as yours lol, damn glue gun :slight_smile:

Niko, heres that thread where kve has a 0.16 tip and hes doing ok so
i can see there being too much of an issue with mine, but like i said, if
there are any i will just take off the top bowl and go back to the 200mm

Albeit i aint sure what the counterweight does :?

I’m just concerned that in a real downpour there will be so much water going through there that it can’t tip fast enough to measure correctly and will under-report, but hey, this is all about experimentation so why not :smiley:

Will find out soon enough, supposed to be some rain tomoz, will see.
I have a manual bucket that i made up myself yesterday (from the met office)
its not 100% perfect but it will give me a fair comparison to work with, i will let
you know how it goes :slight_smile:

Since yesterday we have had a total of 6.7 mm Some was heavy late last night
cause of the bad wind (was banging on the window anyway lol) anyway, i just
checked the manual gauge and it was between 6mm and 7mm. I only did 1mm
increments and it was hard enough doing them lol but from what i can see its
working ok at present.

I suppose it really needs a good downpour to get a proper idea so i will report
again whenever that happens :slight_smile:

Cool :slight_smile:

I think max tips/min is in the specs. Somehow 99 is a figure that springs to mind.

WMR200 (essentially the same gauge?) quotes the ‘range’ as 0 mm/hr - 999 mm/hr,
which I think implies it ought to be able to handle approx. 16 tips a minute, i.e approx. 1.6mm/min with a 0.1mm conversion.

Thanks. I knew 99 came in somewhere :oops:
I wouldn’t really advocate greater than 0.2 mm.

A 10 times standard modification (i.e. 0.1mm) does seem to be pushing it!

If the 1.6 mm/min I calculated is valid, Bashy’s mod might have just been in danger of overload twice here yesterday (i.e. I twice has 2 x 1mm tips in the same minute), but then we probably get a bit more rain on average than he does - and the wind would probably have ripped the big funnel off anyway. :slight_smile:

With a less sensitive fallback in place to catch really extreme events it’s an experiment though. :smiley: