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My Fine Offset rain gauge mod

Discussion specific to Fine Offset and similar rebadged weather stations
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Orion
Posts: 277
Joined: Mon 08 Nov 2010 5:51 pm
Weather Station: WH1081 (Maplin)
Operating System: windows 10 64bit
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My Fine Offset rain gauge mod

Post by Orion » Tue 02 Aug 2011 3:02 pm

This design overcomes most of the problems with the FO rain gauge
1.No movement
2.Improved accuracy
3.Keeps insects out
4.Gauge set 30cm above surrounding area
5.Room to fit heater if required

Think most would agree that the FO under reads because of splash out as the gauge is too shallow
the AREA of the FO is 110x50mm = 5500mm
so a funnel would need to be 83.683mm to give us the same area (in theory) so far found 90mm needed to give accurate results
but this can be reduced 1mm at a time, I used a rotary sander fitted to an electric drill lightly sanding the top of the funnel as needed

for the funnel I purchased a small plant spray bottle co-op 99p
acs-pqc7__.jpg
Mounted Gauge onto a piece of wood with some plastic spacers glued to a concrete slab
P1000600s.jpg
Had this wooden flower pot so painted it with 3 coats of hammerite and cut of some slots for drainage, then fitted the holes with some aluminium mesh to keep insects out
P1000599.JPG
The funnel is made from a plant sprayer, keep the screw lid for fitting, also made a wire mesh cone to fit inside
P1000595.JPG
This is my finished unit with a couple of manual rain gauges for comparing readings
The yellow bit was a plastic sweet jar lid with a hole cut out
P1000594.JPG
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Cambium
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Joined: Wed 03 Aug 2011 11:19 pm
Weather Station: EasyWeather
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Location: Coastal CT, USA
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Re: My Fine Offset rain gauge mod

Post by Cambium » Sun 07 Aug 2011 4:36 pm

Orion wrote:This design overcomes most of the problems with the FO rain gauge
1.No movement
2.Improved accuracy
3.Keeps insects out
4.Gauge set 30cm above surrounding area
5.Room to fit heater if required

This is my finished unit with a couple of manual rain gauges for comparing readings
The yellow bit was a plastic sweet jar lid with a hole cut out
Sweet! Thanks for sharing this info! I was just thinking about ways to make sure all the rain stays within my small rain gauge especially during sideways rain or downpours that might splash out.

My issue is that I have it mounted to the roof so a flower pot wont work to well but you've opened my mind up for sure. :-)

wd40
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Re: My Fine Offset rain gauge mod

Post by wd40 » Sun 07 Aug 2011 6:08 pm

Really nice work. Much, much nicer than my mod.

You might consider on the next version to include the straight sides of the bottom of the spray bottle to help with wind blow over if your new modified gauge measures short of your manual gauge.

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Orion
Posts: 277
Joined: Mon 08 Nov 2010 5:51 pm
Weather Station: WH1081 (Maplin)
Operating System: windows 10 64bit
Location: Paignton Devon UK
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Re: My Fine Offset rain gauge mod

Post by Orion » Mon 08 Aug 2011 11:54 am

Hi WD
The funnel did include 10mm of the straight sides at first but was over reading compared to my 2 manual gauges
the theoretical diameter of the funnel is 83mm
my funnel is now down to 89mm and am slowly reducing the diameter of the funnel 1mm at a time until my readings are all the same the 2 manual gauges
which tend read almost the same most times we get some rain
-Date------- Total-----FO----G1----G2
04/08/2011 335.20 7.80 7.00 7.00
08/09/2011 346.30 11.10 10.00 10.00
last reading was 1.1mm higher then the 2 manual gages for a funnel diameter of 90mm

Cambium
Posts: 97
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Weather Station: EasyWeather
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Re: My Fine Offset rain gauge mod

Post by Cambium » Mon 08 Aug 2011 12:04 pm

Orion wrote:Hi WD
The funnel did include 10mm of the straight sides at first but was over reading compared to my 2 manual gauges
the theoretical diameter of the funnel is 83mm
my funnel is now down to 89mm and am slowly reducing the diameter of the funnel 1mm at a time until my readings are all the same the 2 manual gauges
which tend read almost the same most times we get some rain
-Date------- Total-----FO----G1----G2
04/08/2011 335.20 7.80 7.00 7.00
08/09/2011 346.30 11.10 10.00 10.00
last reading was 1.1mm higher then the 2 manual gages for a funnel diameter of 90mm
Hopefully someone can open my mind here.... When you have a larger area then the gauge itself arent you technically collecting more rain then the gauge is calabirated for? Shouldn't the size of the funnel and sides be the same as the rectangle gauge? I assume thats a teeter todder gauge type.

I'm having a hard time seeing past this thought of mine.

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Orion
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Re: My Fine Offset rain gauge mod

Post by Orion » Mon 08 Aug 2011 4:05 pm

AREA of the FO is 110x50mm = 5500mm
A funnel would need to be 83.683mm for the same area
but as the fine offset is a very cheep device and not very accurate its possible that the collecting device (funnel) may need to be a few mm bigger than the theoretical size of 83.683mm to get most accurate readings
so just reducing the size of the funnel slowly until the FO gauge reads the same as the manual gauges

wd40
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Re: My Fine Offset rain gauge mod

Post by wd40 » Mon 08 Aug 2011 4:26 pm

Roy,I figure you know this already but are you aware there is a way to correct the rain gauge built into Cumulus under the Configuration Tab at the top of the main Cumulus page?

Randy

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Orion
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Re: My Fine Offset rain gauge mod

Post by Orion » Mon 08 Aug 2011 6:30 pm

Yes Randy
But that would take all the fun out of trying to make the FO rain gauge better

wd40
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Re: My Fine Offset rain gauge mod

Post by wd40 » Mon 08 Aug 2011 9:55 pm

I understand completely Roy.

Randy

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