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Rain Collector Measurement

Posted: Thu 23 Feb 2012 11:49 am
by geoffp
Any La Crosse owners know what 1 tip of the rain collector measures, I have the WS-2350 model

Re: Rain Collector Measurement

Posted: Thu 23 Feb 2012 11:56 am
by steve
It's 0.518 mm, inexplicably. It's not even the metric equivalent of a sensible imperial value: 0.02 in = 0.508 mm

Re: Rain Collector Measurement

Posted: Thu 23 Feb 2012 12:01 pm
by geoffp
Many thanks Steve :D

Re: Rain Collector Measurement

Posted: Tue 28 Feb 2012 12:55 pm
by geoffp
Hi Steve, Do I just put the 0.518 mm into the multiplier section?

Re: Rain Collector Measurement

Posted: Tue 28 Feb 2012 1:58 pm
by steve
What do you want achieve by doing that? It would roughly halve your rain figures. The rain gauge tip size is not a logical figure to be using as a calibration multiplier - have you modified your gauge to make it tip with a different amount?

Re: Rain Collector Measurement

Posted: Tue 28 Feb 2012 2:04 pm
by geoffp
Hi Steve, No, I have done no mods, it was just that after the last drop of rain we had the total seemed a bit low, that was why I asked what the one tip figure would be to try and get a more true figure

Re: Rain Collector Measurement

Posted: Tue 28 Feb 2012 3:01 pm
by MickinMoulden
The tip measurement it makes is what it sends, and should be fine. This of course is only good if it is correct, and should be. But some are not Calibrated correctly or just not made fantastic. You could "guess" how much more it should be which sounds like what you are intending to do, but you'll end up more wrong than what the initial "error %" is (assuming there is one).
Best to get a good manual rain gauge. Do some comparisons over a few days of rain (fair amounts, not piddly .2mm/1.3mm etc), and find a good medium. With this "average" worked out, if there is a difference with the averages from your manual rain gauge to your weather station rain gauge, then it would be safe to put in a calibration multiplyer.
Then in the future your manual rain gauge can serve as a check to see that your WX rain gauge is still operating correctly. If you see changes, then it's time to check for spiders webs, leaves, rust, loose conections, water in conections, flat batteries etc.

Re: Rain Collector Measurement

Posted: Tue 28 Feb 2012 3:10 pm
by geoffp
Thanks for that Mike, I have a proper calibrated rain guage so will check it over the next few rainfalls :D