Intermittent very slight drizzle over the past 24 hours has produced a
total of 0.9 mm in the manual rain gauge but the Davis Vantage Pro has
not registered anything. There's a lot of water stuck to the inside
walls of the funnel but the individual drops are too small to run down
to the bottom so the precipitation has not actually reached the tipping
bucket.

Does anyone know of a magic potion that can be applied to the inside of
the funnel to help even very small drops of water to run down?

Norman.
(delete "thisbit" twice to e-mail)
--
Norman Lynagh Weather Consultancy
Chalfont St Giles
England

Norman
I have the Davis WM2 wired version and have found this a problem with all
rainfall. I have a Snowdon type MO gauge that I check it against and over
a period of say 4 to 6 weeks the rainfall amounts in the Davis Guage
decrease.(because of debris and minute particles of dirt) . I have found
this to be the same problem as you are describing. Water droplets remain in
the buckets and you miss the tips, or water on the funnel does not make it
to the buckets.

My solution and it works- Increases the rainfall by up to 10%!

Use a silicon polish on the funnel and inside the buckets. Obviuosly care
has to be taken with overspray on the reid switch. Use cotton buds on the
buckets soaked with polish. This results in all the little droplets
cascading off the polished surfaces, just like they do off a polished car
surface.

Regards
Rob
Farsley


"Norman Lynagh" wrote in
message ...
Intermittent very slight drizzle over the past 24 hours has produced a
total of 0.9 mm in the manual rain gauge but the Davis Vantage Pro has
not registered anything. There's a lot of water stuck to the inside
walls of the funnel but the individual drops are too small to run down
to the bottom so the precipitation has not actually reached the tipping
bucket.

Does anyone know of a magic potion that can be applied to the inside of
the funnel to help even very small drops of water to run down?

Norman.
(delete "thisbit" twice to e-mail)
--
Norman Lynagh Weather Consultancy
Chalfont St Giles
England

In message , ROBERT BROOKS
writes

Norman
I have the Davis WM2 wired version and have found this a problem with all
rainfall. I have a Snowdon type MO gauge that I check it against and over
a period of say 4 to 6 weeks the rainfall amounts in the Davis Guage
decrease.(because of debris and minute particles of dirt) . I have found
this to be the same problem as you are describing. Water droplets remain in
the buckets and you miss the tips, or water on the funnel does not make it
to the buckets.

My solution and it works- Increases the rainfall by up to 10%!

Use a silicon polish on the funnel and inside the buckets. Obviuosly care
has to be taken with overspray on the reid switch. Use cotton buds on the
buckets soaked with polish. This results in all the little droplets
cascading off the polished surfaces, just like they do off a polished car
surface.

Regards
Rob
Farsley

Many thanks, Rob. I'll give it a try. Thanks also to others who have
responded.

Norman.
(delete "thisbit" twice to e-mail)
--
Norman Lynagh Weather Consultancy
Chalfont St Giles
England

On Sun, 07 Nov 2004 10:09:55 GMT, ROBERT BROOKS wrote:

Use a silicon polish on the funnel and inside the buckets.

This certainly helped my WM918 record better. A squirt of Mr Sheen and
a good polish means that the water beads and runs down far better. I
haven't done the buckets but they empty anyway at least well within
the 1mm (7.5ml) resolution of the gauge.

The WM918 also comes with a fine wire mesh "leaf trap" this retains
several ml of water before releasing it...
--
Cheers
Dave. pam is missing e-mail

"Norman Lynagh" wrote in
message ...
Intermittent very slight drizzle over the past 24 hours has produced a
total of 0.9 mm in the manual rain gauge but the Davis Vantage Pro has not
registered anything. There's a lot of water stuck to the inside walls of
the funnel but the individual drops are too small to run down to the
bottom so the precipitation has not actually reached the tipping bucket.

Does anyone know of a magic potion that can be applied to the inside of
the funnel to help even very small drops of water to run down?

Norman.
(delete "thisbit" twice to e-mail)
--
Norman Lynagh Weather Consultancy
Chalfont St Giles
England

I found that the problem becomes less marked as the funnel ages; when new
the water tended to form globules and did not reach the tipping bucket.
Having sid that I think it still under records rainfall in drizzle as the
0.3mm since midnight seems low given the size of the puddles that have
formed.

My worry about applying anythig to the funnel is that it could make the
problem worse.

Alan

On Sun, 7 Nov 2004 10:13:51 -0000, Alan Gardiner wrote in


Intermittent very slight drizzle over the past 24 hours has produced a
total of 0.9 mm in the manual rain gauge but the Davis Vantage Pro has not
registered anything. There's a lot of water stuck to the inside walls of
the funnel but the individual drops are too small to run down to the
bottom so the precipitation has not actually reached the tipping bucket.

Does anyone know of a magic potion that can be applied to the inside of
the funnel to help even very small drops of water to run down?

I found that the problem becomes less marked as the funnel ages; when new
the water tended to form globules and did not reach the tipping bucket.
Having sid that I think it still under records rainfall in drizzle as the
0.3mm since midnight seems low given the size of the puddles that have
formed.

I would agree with the idea age is a factor. Many years ago, I noticed how
water globules tended to remain on the inside of new standard 5" gauges and
not run down into the collector. As part of an experiment on comparing
ground level gauges with the those at the standard height, I compared two
at the standard height - one new(ish) and one old. At times of lowish
rainfall, there was a significant deficit measured by the new one. Trouble
is the figures have left my head.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 07/11/2004 10:34:21 UTC

Mike Tullett" wrote in message
...
On Sun, 7 Nov 2004 10:13:51 -0000, Alan Gardiner wrote in


Intermittent very slight drizzle over the past 24 hours has produced a
total of 0.9 mm in the manual rain gauge but the Davis Vantage Pro has
not
registered anything. There's a lot of water stuck to the inside walls of
the funnel but the individual drops are too small to run down to the
bottom so the precipitation has not actually reached the tipping bucket.

Does anyone know of a magic potion that can be applied to the inside of
the funnel to help even very small drops of water to run down?

I found that the problem becomes less marked as the funnel ages; when
new
the water tended to form globules and did not reach the tipping bucket.
Having sid that I think it still under records rainfall in drizzle as the
0.3mm since midnight seems low given the size of the puddles that have
formed.

I would agree with the idea age is a factor. Many years ago, I noticed
how
water globules tended to remain on the inside of new standard 5" gauges
and
not run down into the collector. As part of an experiment on comparing
ground level gauges with the those at the standard height, I compared two
at the standard height - one new(ish) and one old. At times of lowish
rainfall, there was a significant deficit measured by the new one.
Trouble
is the figures have left my head.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 07/11/2004
10:34:21 UTC

I used to crew on the Admirals Cup and before all the racing and after the
press had taken the pictures of the boat out of that water we used to wet
and dry the hull. The theory being this is you get a layer of water sticking
to the surface and this reduced the friction of the water passing the hull.
Polish was a big no no below the water line. So I guess this could be said
for the rain bucket. The hole does block up quite quickly if its been dry
then wet and then dry again.

Steve

--
The UK SpeedTrap Guide" @ www.ukspeedtraps.co.uk
The UK Weather Guide" @ www.ukstorms.com