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Weather Station Hardware => Hydreon RG-11 Optical Rain Gauge/Sensor => Topic started by: DaleReid on April 12, 2017, 11:42:41 AM

Title: Any success stories?
Post by: DaleReid on April 12, 2017, 11:42:41 AM
I've read through this section, thinking this device might be a way to implement a lower cost (than tipping bucket and mount) rain gauge with some ambitions to put up a few more remote stations this summer.

Yet it seems to be a pretty hit and miss for actually doing much more than saying it rained or not.

One of the other discussions mentioned trying to use a funnel to collect the rain and thus reduce the errors of variable drop size and widely spaced drops.  I wonder if anyone has tried this yet?  The nice thing is that not a very big throat would be needed to collect and concentrate the rain. On the other hand, if the rain rate is high, there may be more of a stream than drops.  With a tipping bucket drops aren't necessary so even if it is coming down in a real frog strangler, the buckets still collect.

Just curious if there has been any more experimenting with this gizmo.
Dale
Title: Re: Any success stories?
Post by: kmahler on April 14, 2017, 03:30:48 AM
I've read through this section, thinking this device might be a way to implement a lower cost (than tipping bucket and mount) rain gauge with some ambitions to put up a few more remote stations this summer.

Yet it seems to be a pretty hit and miss for actually doing much more than saying it rained or not.

One of the other discussions mentioned trying to use a funnel to collect the rain and thus reduce the errors of variable drop size and widely spaced drops.  I wonder if anyone has tried this yet?  The nice thing is that not a very big throat would be needed to collect and concentrate the rain. On the other hand, if the rain rate is high, there may be more of a stream than drops.  With a tipping bucket drops aren't necessary so even if it is coming down in a real frog strangler, the buckets still collect.

Just curious if there has been any more experimenting with this gizmo.
Dale

I have two of these in my cache of weather instruments. So far my experience has been what you described. It's good for raining or not indication but not as an accurate measurement device. I seriously doubt it could be turned into one. IMHO, SLOweather has the most experience with these devices and I suspect he would tell you that same as I just did.

They are great devices and fun to experiment with but, I'd never use one to measure anything other than It's Raining or not and maybe how hard.
Title: Re: Any success stories?
Post by: SLOweather on April 14, 2017, 09:20:48 AM
Well, I've played with it a lot. Actually, "them" as I have 3.

Even on their website they say:

Quote
What is the accuracy of the RG-11 Rain Gauge?

The Hydreon Rain Gauge is not as accurate as a properly maintained Tipping Bucket in ideal conditions. 
We do not claim an accuracy specification for the RG-11 Rain Gauge.  The RG-11 is very repeatable, and over a variety of conditions will yield an average result that is reasonably close to that of a tipping bucket.  But, for any given rainstorm the result can be off by as much as 2:1 in either direction.   Even this is not an upper limit.

The strength of the RG-11 is that it works in many situations where a tipping bucket simply does not.  That is, the Rain Sensor is vastly more accurate than a tipping bucket that has ceased to work properly due to dirt or mineral deposit or mechanical difficulty, or a tipping bucket in a mobile application that is constantly giving false indications due to motion.  The RG-11 is more accurate for a small (but in some applications, meaningful) amount of rain, such as 0.01", that will simply not register in a tipping bucket.

This said, if you do not need the ruggedness of the Hydreon Rain Gauge, and maintaining the tipping bucket is not a problem, use a tipping bucket.

That pretty much sums it up. You might try contacting them and seeing if the firmware has been improved since it was introduced. And, at $60US it's inexpensive enough IMO to buy one to experiment with.

As you note, I don't know what you would gain from using a funnel. Like any rain gauge, it's apparently designed for the area of the clear lens. I say "apparently" because I did talk with them once and they either didn't know or wouldn't tell me the active diameter or area.

I'm using them more as an "It's raining" indicator, and also as a faster intensity indicator than a tipping bucket.
Title: Re: Any success stories?
Post by: miraculon on April 14, 2017, 12:31:18 PM
I used mine in a 0.001" tip emulation mode. I have it connected to my Davis T/H station masquerading as an ISS for the MB Pro.

I use it to detect the onset of rain and determine start / stop times. There is too much lag in the regular TBR gauges.

Here is my plot from this gauge:

(http://www.miraculon.com/weatherdata/hydreon.png?with=query)

Greg H.