Topic: WH40 vs WH65 Rain Measurements

[Gyvate]

I noted that your WH40 extension is white. I'm curious to know whether that was a deliberate choice.
To my mind black seems the wrong colour for a rain funnel.

From an aesthetic point of view white was my colour of choice.
Black would imo have been over-dominating - notwithstanding the fact that it would attract too much heat.
Any other fancy colour like red or blue or ... I wouldn't have liked - and as I see it +/- every day, I didn't want to intentionally hurt my eye.

[CW2274]

I noted that your WH40 extension is white. I'm curious to know whether that was a deliberate choice.
To my mind black seems the wrong colour for a rain funnel.

Black would imo have been over-dominating - notwithstanding the fact that it would attract too much heat.

Rainwise and Davis's are black. I kinda figured it was to help melt snow. If your bucket drains properly, evaporation should be inconsequential.

[Gyvate]

Rainwise and Davis's are black. I kinda figured it was to help melt snow. If your bucket drains properly, evaporation should be inconsequential.

For snow and ice I have a thermostat triggered 15 W reptile terrarium heating coil built inside the rain gauge body - based on DIY instructions for a Davis  .
Works perfectly.

[DelChard]

@Gyvate @CW2274
Thankyou for your comments.
Aesthetically, the colour wouldn't concern me (I can't normally see my WH40).
Apart from my lunatic notion of grafting on an aerocone, I had been wondering whether painting it white would be a good idea.
This was born from my wife's penchant for large expensive vehicles (providing they are black).
So, I have frequently witnessed a 3 to 4 inch dense fog layer above the roof of said vehicle (the weather here has a habit of tipping it down, even in bright sunshine).
With the standard WH40 cone, I believe that may be an issue.
I'm now guessing the aerocone shouldn't be afflicted.

Footnote for Gyvate's latest post.
Snow is not normally an issue for my locale, but maybe your extension may help to a degree.
I had noticed that some Davis users swap cones for the winter.

Thankyou both

[DelChard]

I got my wish for a dry day 
OK, my preferred option turned out to be a dead duck.
The base of the aerocone has 2 mounting lugs, that wouldn't pass over the WH40 cone.
I ended up using a variation of option 1. After checking that the aerocone cleared the base of the WH40, I cut a nice hole in the new WS65/69 cone.
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Hot glued the modified cone inside the aerocone, added the bird spikes.
15mins later.
Et voila.
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Checked level with a spirit level.
Possibly the only WMO compliant WH40????

For now I've put in a gain of 1.18 to compensate for the different diameters.

I nearly ordered a stratus.
Only UK source is Amazon....loads of sellers....all using convenience addresses with the directors tracing back to Turkey 
I don't have anything against Turkey, just the practice.
I'll wait to see how this performs against the WS69 (now has the debris screen from my original WH40 funnel).
Might go for the Climet manual (doesn't have the resolution of the stratus), or wait for the next extended dry spell to run a known volume of water through it. Should be 540ml for 1" of rainfall (I know I mix units, But my rainfall is recorded in inches).

[DelChard]

Well, someats changed.
For the first time ever my WH40 has recorded more rain than my WS69.
The bad news, not very much, and not particularly heavy 

[Rover1822]

What was the variance compared to a manual?

[DelChard]

What was the variance compared to a manual?

That's the reason I didn't put any values.
As previous, supposed UK sellers of stratus all lead back to Turkey and appear a tad dubious.
I'm not sure what to do on that front.
A true calibration, would be running water through the gauge and catching and weighing the amount.
But then my scales aren't traceable to national stds!!

Edit
Just found on prodata (they just call it cocorahs)

[Rover1822]

I was goofing around earlier, and had a thought based on a previous image for an add-on.

To me, something like this would work, just a design idea, I don't have a 3D printer, or know what is possible in manufacturing. This is a cut away image
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[DelChard]

The clip on bit would take a bit of cleaning out (I use to buy a lot of RPs and purchased our own thermojet printer back in the late 90s)

Reason I didn't choose that route, was the height needed to make it WMO compliant.

I'm slowly morphing into a nut job.

[Rover1822]

The clip on bit would take a bit of cleaning out (I use to buy a lot of RPs and purchased our own thermojet printer back in the late 90s)

Reason I didn't choose that route, was the height needed to make it WMO compliant.

I'm slowly morphing into a nut job.

Lol , just a thought process. Also none of that was truly to scale, more freehand
There are other options to the clips being molded, something as simple as a reversed plastic piece used for a mirror or glass clip as separate piece. The one thing I liked is is the groove on the upper fitting the lower

[DelChard]

I believe the Zinz version has a similar groove, Gyvate just used sticky tape to hold his in place.

[Rover1822]

Other option is to have a ring that surrounds the original cone, for the accessory to either clamp to , or screw down to like a sink flange
The groove still be in play, but maybe not need it, as long as the interior edge prevents water escape, so still a lip .

anyway, too much musing on my end, not buying a 3D printer just for this, already have too much stuff I use rarely

[Gyvate]

I believe the Zinz version has a similar groove, Gyvate just used sticky tape to hold his in place.

That was the temporary approach.
Now I will glue some textile tape around the WH40 rim edge so the extension can sit tighly on the rim.
It's just that the groove is a wee bit too wide. With the textile tape it can fit/sit tighly.

[DelChard]

Other option is to have a ring that surrounds the original cone, for the accessory to either clamp to , or screw down to like a sink flange
The groove still be in play, but maybe not need it, as long as the interior edge prevents water escape, so still a lip .

anyway, too much musing on my end, not buying a 3D printer just for this, already have too much stuff I use rarely

Simplest option.
Wrap some sheet aluminium round the cone and clamp in place with a large hose clamp.

[DelChard]

Just heavy condensation this morning, and no rain forecast.
So moved the WH40 back to the table, changed my assignments and set the rain gain back to 1.
I had a concern about the raised height of the cone outlet, being approx 2in, affecting the capability (danger of rain missing the spoon).
I simulated a heavy rain shower (garden spray gun), but couldn't register more than 4in/hr.
So, I've now replaced the piece of the WS69 cone that I'd cut out. And registered 12in/hr.
Does mean that I'll need to flush out periodically.
Re measured and recalculated a value of 549.72ml for 1in of rain.
Ran my calibration test. capturing the water in a pre-weighed jug.
Jug weight 1028g
Total weight 1715g
Vol of water captured 687ml or 1.249732209in of rain.
My weewx recorded 1.02in
Giving me a rain gain of 1.21, slightly higher than the 1.18 I had calculated from the difference in diameters.

Now waiting for some genuine rain, and delivery of a manual gauge for a comparison test.

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[kheller2]

Bump.  I'm curious if there was a comparison test.

[kheller2]

Sometime I wonder if my manual Stratus gauge is off.  Once the manual gets close to 1" the WH40 starts to pull ahead.
I was looking at the specs of the unit...

"Rainfall measuring range: 0--6000mm ; Accuracy: ±5% Sensor reporting interval: 49 seconds"

So ±5% of mm? of inches? of? (doesn't matter, its a %)
In my case the Stratus reported 1.62", the WH40 1.75", the WH65 1.83" (this guy is higher up on poles so I expect this to be slightly higher) the Stratus and WH40 are next to one another at the same height. 

Anyhow...   in my case that is 8% over the manual value.   After cleaning, and inspecting the unit -- would I drop the rain offset by 8% so instead of 1.0 it would be .92 ?

Also ... what does it mean by a range of up to 6000mm?  It breaks after 236" of rain? 

[davidefa]

would I drop the rain offset by 8% so instead of 1.0 it would be .92 ?

Also ... what does it mean by a range of up to 6000mm?  It breaks after 236" of rain? 

Yes, to reduce your actual gain by 8% multiply it by 0.92 ( in your case, i think 1 * 0.92 = 0.92 )
The 6000mm limit derives from the 16bit count value the sensor transmits ( 65535 *0.1mm = 6553.5mm )... but when the count nears 59999 you better watch out of strange fellows loitering around your sensor...