Topic: Can a weather station actually be accurate without a fan?

[nincehelser]

Sounds about the same as when the fan in an Acurite 5n1 stops running.  I'm not sure if there's any sort of consistency between different brands and models, though.

[miraculon]

When I finally get the Davis instruments station, I'll set it up side by side, and we'll see what the difference is. Right now I am extrapolating based on what time the sun hits the shield. Temps literally go up 10 degrees at that point over a relatively short period of time.

I have a continuous plot of the temperature in the Davis Temperature/Humidity station (6382) and the ISS equipped with DFARS. The ISS was originally a non-aspirated version (6152) and I upgraded it to DFARS. In the original location in Livonia, Michigan (USA) the ISS was located in the shade except for the very early morning. Here in Rogers City, MI the ISS is in a sunnier location. The Temp/Hum station has a passive shield.

The Temp/Hum station is located on my deck and is in the shade during the afternoon. The ISS is out in the sun (when shining  ). This difference is calculated on a Meteohub and uploaded continuously.

Plot of the Difference Between Davis ISS Temp/Hum Station in °F. A positive difference signifies that the ISS temperature is higher than the T/H Station temperature.


Here is a small html table showing the difference. (it includes an indoor/outdoor comparison in addition to an average ISS/T-H station temperature calculation)

http://www.rogerscityweather.com/tempdeltas.html

Greg H.

[Axel]

OK, the verdict is in, the Ambient Weather 2080 radiation shield is ineffective.

Daytime delta: 3-4F
night time delta: 0-2F, function of wind.

I am going to hook up both stations to Wunderground to track the difference.

[DoctorKnow]

Really it's not "ineffective", it's just that it isn't "perfect". Creating a chimney effect with black paint would likely make it accurate to plus 1 or 2 degrees in the sun.

[nincehelser]

Really it's not "ineffective", it's just that it isn't "perfect". Creating a chimney effect with black paint would likely make it accurate to plus 1 or 2 degrees in the sun.

And you're basing that on what, exactly?

[DoctorKnow]

Really it's not "ineffective", it's just that it isn't "perfect". Creating a chimney effect with black paint would likely make it accurate to plus 1 or 2 degrees in the sun.

And you're basing that on what, exactly?

Aren't you fast on the trigger today?

I am basing it on the owners experience, saying the original shield yielded 10 degrees too high, and now the bigger shield yields 3.5 degrees high. So the shield is making a difference, just not quite to where it needs to be. Some basic modifications will get Axel where he likely wants to be. Just like the acurite 5 in 1, it can be made right, and painting is the easiest way that myself and others have found to be quite effective and if you search around at the reviews of this particular radiation shield on Ambient and Amazon, you will see other owners have taken this path also.

Nincehelser have you bothered to paint old yeller yet so you can be a part of the paint statistics? 

[Langis]

Info regard accurate without a fan.

Sorry for my poore English here.

This is the official recomadation from the metrolocical institute in norway.

Temp sensor should not be mounted in the shade.!!

Temperature and Humidity:
Air temperature sensors should be mounted between 1.2 and 2 m above the ground, radiation sensor
humidity can be placed in the same cabin. The measurement location should be a 50 m² flat, grassy area (7m x 7m)
with large distance to the forest, buildings, water, etc. The sensor should preferably NOT be in the shade as it affects
radiation conditions and temperature errors.

Sorry this pdf is in Norwegian but use of Google translate shuld help you on the way With info. (dont thrust 100% Translation)

So if you need fan or not!!!! i supose the positioning its wrong anyway regards to official messurements, espesialy around Your house.

my davis vp2 station has 24 h fan, position at "top of house" middle of norway, coast area.

My station CWOP compare to surronding stations here:
ENAL is the official used by metrolocical insttitute in norway as  www.yr.no.
http://www.ulsteinvikweather.com/uw/wxcwopstats.php

[Cutty Sark Sailor]

Re: Can a weather station actually be accurate without a fan?
yes,.

[Langis]

Re: Can a weather station actually be accurate without a fan?
yes,.

As long critiria for messurements are meet!! Yes it can.

[nincehelser]

Aren't you fast on the trigger today?

I am basing it on the owners experience, saying the original shield yielded 10 degrees too high, and now the bigger shield yields 3.5 degrees high. So the shield is making a difference, just not quite to where it needs to be. Some basic modifications will get Axel where he likely wants to be. Just like the acurite 5 in 1, it can be made right, and painting is the easiest way that myself and others have found to be quite effective and if you search around at the reviews of this particular radiation shield on Ambient and Amazon, you will see other owners have taken this path also.

Nincehelser have you bothered to paint old yeller yet so you can be a part of the paint statistics? 

In other words, you don't know what you're talking about.

Was it from the same Amazon folk that gave you the idea changing your wind readings to metric would make them counter the effects of wind blockage and low reporting?

[DoctorKnow]

Aren't you fast on the trigger today?

I am basing it on the owners experience, saying the original shield yielded 10 degrees too high, and now the bigger shield yields 3.5 degrees high. So the shield is making a difference, just not quite to where it needs to be. Some basic modifications will get Axel where he likely wants to be. Just like the acurite 5 in 1, it can be made right, and painting is the easiest way that myself and others have found to be quite effective and if you search around at the reviews of this particular radiation shield on Ambient and Amazon, you will see other owners have taken this path also.

Nincehelser have you bothered to paint old yeller yet so you can be a part of the paint statistics? 

In other words, you don't know what you're talking about.

Was it from the same Amazon folk that gave you the idea changing your wind readings to metric would make them counter the effects of wind blockage and low reporting?

Nobody here knows anything but you. 

[nincehelser]

Nobody here knows anything but you. 

The science and math are pretty simple.

[Cutty Sark Sailor]

Just go away DoctorKnow... when you can claim something besides Wunderweenies for a web site, we might start paying attention to your BS..,.,.  that's all it is as far as I'm concerned... as I said on another thread... 'Stuff it'...

[DoctorKnow]

I'm not ever going to stop, because you will never deviate from your program either of trying to shut down any group who doesn't see things exactly your way. That's the way science rolls.

[ggsteve]

I know I'm relatively new here, but do you guys want to tone it down a notch?  It's a weather forum for goodness sake.  Everybody is entitled to their opinion, but you can do it without insulting others.

[nincehelser]

I'm not ever going to stop, because you will never deviate from your program either of trying to shut down any group who doesn't see things exactly your way. That's the way science rolls.

Anyone who constantly makes gross errors in matters of simple fact, like where a temperature sensor is located and how it operates, is not conducting science.  You can find these things in the manufacturer's data sheets (Senserion and Acurite).  They are not matters of your "opinion".

You just keep polluting the board with incorrect information.  Over and over and over.

[Axel]

It's nice that everyone has all these theories, but I have the Ambient 2080 and the Davis Instruments vantage pro2 within two feet of each other, correctly placed according to NOAA standards and the experimental results don't lie. They DO NOT read the same. For example, yesterday, 87F on the Ambient Weather versus 83F on the 2080. The night time delta is smaller but it's still there.

This does significantly decrease my confidence in all the readings from personal weather station data on Wunderground. I can throw out my last four years of data collection.

[DoctorKnow]

I'm not ever going to stop, because you will never deviate from your program either of trying to shut down any group who doesn't see things exactly your way. That's the way science rolls.

Anyone who constantly makes gross errors in matters of simple fact, like where a temperature sensor is located and how it operates, is not conducting science.  You can find these things in the manufacturer's data sheets (Senserion and Acurite).  They are not matters of your "opinion".

You just keep polluting the board with incorrect information.  Over and over and over.

I think you don't want to admit that there needs to be a change in the design of a product for it to be within 2 degrees. It's documented time and again that these sensors are nearly 10 degrees too high when placed according to NOAA recommendations in the sunshine. There are only a few  companies that seem to have the right processes down for accurate temperatures in the sun that I know of including Davis, Rainwise, and the new Ambient all in one. The acurite with one solar panel has to be painted and more solar panels added. The dual panel still reads high from what others have experienced. The ambient radiation shield also needs either a fan or painting. These are real world results from real people. The chips in the sensors have little to do with it. They are not perfect themselves, but they are not 10 degrees off.

[Cutty Sark Sailor]

 

I'm not ever going to stop, because you will never deviate from your program either of trying to shut down any group who doesn't see things exactly your way. That's the way science rolls.

Anyone who constantly makes gross errors in matters of simple fact, like where a temperature sensor is located and how it operates, is not conducting science.  You can find these things in the manufacturer's data sheets (Senserion and Acurite).  They are not matters of your "opinion".

You just keep polluting the board with incorrect information.  Over and over and over.

Yep.. and apparently without any real experience... two thumbs on a smart phone with instant results is not the same as 10 fingers on a keyboard, building a site, optimizing our equipment, researching and establishing  'base line' at our locations... assuming 'Wunderweenies' is the epitome of weather 'smartness' is not where most of us are at. But then, we don't know what the hell we're talking about... ... further more, anyone with a handle of "DoctorKnow" should also study a bit on narcissism... and the rest of us should understand, and we are  so we should just quit, as Steve suggested. Let 'im figure it out for himself.

[nincehelser]

I think you don't want to admit that there needs to be a change in the design of a product for it to be within 2 degrees. It's documented time and again that these sensors are nearly 10 degrees too high when placed according to NOAA recommendations in the sunshine. There are only a few  companies that seem to have the right processes down for accurate temperatures in the sun that I know of including Davis, Rainwise, and the new Ambient all in one. The acurite with one solar panel has to be painted and more solar panels added. The dual panel still reads high from what others have experienced. The ambient radiation shield also needs either a fan or painting. These are real world results from real people. The chips in the sensors have little to do with it. They are not perfect themselves, but they are not 10 degrees off.

(*sigh*)  You don't seem to want to understand that there are many of us who are *NOT* having problems.   There you go again with your crazy claims that "The acurite with one solar panel has to be painted and more solar panels added".  That's simply not true.  Mine works fine, for example, as do many others.  Yes, some people have particular issues, but it's not everyone.

More specifically what i'm talking about are your claims on where components are located in the equipment and what they do.  If you can't even locate the temperature sensor on a 5n1, you aren't terribly qualified to be telling other people about how "badly" it's designed.

And now you try to tell others how equipment you haven't even owned or used operates? 

[DoctorKnow]

When people have problems, what do they do? They go to their friend the "google" and do a search. That's what brought me here. Not everyone is going to sign up and tell their experience...

I believe posters when they tell me their issues. I share my real world experiences. That's how you get a well built product. Testing and sharing your results.

You don't stick like glue to what's on paper and call it "science".

And no I didn't tear into my 5n1 looking for the sensors. What I do know is it needs ventilation and shielding. Every station does. Ventilation does not mean it should have to have a fan either.

As far as working fine, my rain gauge is excellent, my temp is within 2 degrees, my humidity is within 8% and my dewpoint is within 3. That's not perfect, but it is as good as any other brand.

When I see your graphs on Wunder, I see "Spikes" like mine used to have.

[nincehelser]

When people have problems, what do they do? They go to their friend the "google" and do a search. That's what brought me here. Not everyone is going to sign up and tell their experience...

I believe posters when they tell me their issues. I share my real world experiences. That's how you get a well built product. Testing and sharing your results.

You don't stick like glue to what's on paper and call it "science".

And no I didn't tear into my 5n1 looking for the sensors. What I do know is it needs ventilation and shielding. Every station does. Ventilation does not mean it should have to have a fan either.

As far as working fine, my rain gauge is excellent, my temp is within 2 degrees, my humidity is within 8% and my dewpoint is within 3. That's not perfect, but it is as good as any other brand.

When I see your graphs on Wunder, I see "Spikes" like mine used to have.

Wow.  You are one confused person.

I shared my results comparing an old, yellowed 5n1 to a brand new shiny white one.  You called me a liar and claimed I was trying to undermine you.

Then there are those who tried your idea and didn't get results like yours that you labeled "skeptics".

You sir, are a hypocrite of the highest order.

Given you think you are an expert, why don't you explain to everyone your claim that a lower temperature reading doesn't impact the relative humidity reading on the 5n1?

As I've said before, you have no idea how your own equipment works.  I doubt you even understand the mathematical relationship between temperature and relative humidity.

[DoctorKnow]

ROFL.

You have a nice day. Maybe you could go run the spider out of ole yeller again...

[PaulMy]

This is now beyond good debate.  Please both of you, IF you want to reply then reply in a respective manner, but perhaps best NOT to respond with the current emotions!
 
Paul

[capeweather]

Please stop! If you want to discuss this further, exchange phone numbers! Thank you!