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Old October 20th 04, 11:35 AM posted to uk.sci.weather
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Default Davis Humidity problem :-0

I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make a
software adjustment?

Keith (Southend)



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Old October 20th 04, 12:19 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0

keith.r.harris wrote:
I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make a
software adjustment?

Keith (Southend)


Have you first checked that there has not been a very high tide, which
has reached your garden? :-)

--
Howard Neil
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Old October 20th 04, 12:51 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0

"keith.r.harris" wrote in message ...
I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make a
software adjustment?

Keith (Southend)


Hi Keith,

It's a wonder you can see anything with a humidity of 103%
Can you get hold of a wet/dry bulb hygrometer and
re-calibrate it in the software.

Regards,

Rob
Chester, UK
http://www.west-cheshire.ac.uk/weather/


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Old October 20th 04, 12:59 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0

97% now, the tide must have gone out :-)

Keith (Southend)

"Howard Neil" wrote in message
...
keith.r.harris wrote:
I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make

a
software adjustment?

Keith (Southend)


Have you first checked that there has not been a very high tide, which
has reached your garden? :-)

--
Howard Neil



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Old October 20th 04, 02:40 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0

There used to be an automatic tide gauge at the end of Southend Pier. If
it is still there, I wonder if you could link it to your weather
station? :-)

Regards

Howard Neil

keith.r.harris wrote:
97% now, the tide must have gone out :-)

Keith (Southend)

"Howard Neil" wrote in message
...


Have you first checked that there has not been a very high tide, which
has reached your garden? :-)

--
Howard Neil



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Old October 20th 04, 03:15 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0

I have a wet/dry bulb, I will have to get it set up again.

Thanks

Keith (Southend)

--
'Weather Home & Abroad'
http://www.southendweather.net
e-mail: keith_harris9athotmail.com

"Rob Bale" wrote in message
...
"keith.r.harris" wrote in message

...
I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make

a
software adjustment?

Keith (Southend)


Hi Keith,

It's a wonder you can see anything with a humidity of 103%
Can you get hold of a wet/dry bulb hygrometer and
re-calibrate it in the software.

Regards,

Rob
Chester, UK
http://www.west-cheshire.ac.uk/weather/




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Old October 20th 04, 05:56 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0



keith.r.harris wrote in message ...
I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make a
software adjustment?

Keith (Southend)



Keith my Davis measures humidity and calculates dewpoint on the console ?
The humidity instrument will only go from 0 to 100%. So I cannot understand what
you mean by software ? Does your Davis measure other humidity variables and
calculate humidity ? In which case your formula needs investigation.

Will.
--

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Old October 20th 04, 07:22 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0

Ah, I think I found the problem.

Sometime ago I used a wet/dry and the hourly metar readings from
Southend Airport and compared each hour with what my Davis was
reading. I calculated the average deviation and made the necessary
adjustment on the console. Subsequently, I 'tweaked' the reading up by
7%. Unfortunately I seem to remember I was told that the accuracy
above 90% RH is not good with these sensors and upto now I have not
had a problem. However, I obviously need to tweak things back a tadge.

I have tweaked it back 3%...

All the same I will have another monitoring excersise to do.

Thanks

Keith (Southend)

***********************
Weather Home & Abroad
http://www.southendweather.net

On Wed, 20 Oct 2004 18:56:59 +0100, "Will"
wrote:



keith.r.harris wrote in message ...
I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make a
software adjustment?

Keith (Southend)



Keith my Davis measures humidity and calculates dewpoint on the console ?
The humidity instrument will only go from 0 to 100%. So I cannot understand what
you mean by software ? Does your Davis measure other humidity variables and
calculate humidity ? In which case your formula needs investigation.

Will.


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Old October 20th 04, 09:53 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0

Keith (Southend) wrote:

Ah, I think I found the problem.

Sometime ago I used a wet/dry and the hourly metar readings from
Southend Airport and compared each hour with what my Davis was
reading. I calculated the average deviation and made the necessary
adjustment on the console. Subsequently, I 'tweaked' the reading up by
7%. Unfortunately I seem to remember I was told that the accuracy
above 90% RH is not good with these sensors and upto now I have not
had a problem. However, I obviously need to tweak things back a tadge.

I have tweaked it back 3%...

All the same I will have another monitoring excersise to do.


You might also need to monitor at the same location -- relative
humidity can vary considerably over relatively short distances
depending on the immediate environment as well as temperatures.

Nor are you likely to find an accurate linear relationship between the
Davis sensor and values derived from a Mason hygrometer (wet and dry
bulb). Mine varies by at least 5%, and possibly much more, across the
normal range of observations -- which, IMHO, makes it doubtful if
there's ever any point in tweaking.

--
John H
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Old October 20th 04, 10:05 PM posted to uk.sci.weather
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Default Davis Humidity problem :-0


"keith.r.harris" wrote in message
...
I see that the humidity in my back garden is 103% ~ what next!

Anyone else encountered this problem? Is it possible I just need to make
a
software adjustment?

Keith (Southend)


100% is the highest my VP has shown and I would have thought that the
software would not permit a higher reading.

Alan




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