Topic: Interested in Seperates

[Jim Beam]

Hi All,

new here, first post.

I have been looking over the forums to get an idea of what weather stations are out there. From my reading it appears that the anemometer needs to be at 10m off the ground (ideally) and the temp/RH want to be at 1.8 - 2m off the ground and the rain gauge close to the ground (all this being the most ideal way to do it)

It seems the Davis pro does this.

If i wanted to go higher end then this, are separates a better way of going about this?

How would i then get each of the seperates into a computer program to log/display/ transmit this data?

Columbia has nice gear as does Young and a few others.

I am looking for "reasonable" accuracy. I am not a public weather station but gathering the wind speed/direction/, Temp/RH, rain fall and solar irradiance is important to me for planning various things i want to do. So accuracy is important but i dont need 0.0001 accuracy either. But pretty good to really accurate would be where i want to be. I understand the higher end i go the better the quality and accuracy.

Also, i am in the middle of Africa. I need reliable equipment as its not easy/cheap to be shipping in spare fans and the like.

Thoughts?

Rgds

J.B

[Jáchym]

Hi,
first of all welcome to the forum, I think Davis VP2, in the Plus version, which also includes solar and UV sensor, is accurate enough. It has the sensors separate so you can place the wind sensor 10m above the ground and the ISS have 2m above the ground. You probably will not find a better option if you don´t want to go to really professional calibrated stations like Vaisala, where we are talking in completely different price levels and for people like you or me, who only want to record the weather, this is an overkill

[Jim Beam]

Thanks for the welcome Jachym.

I sort of get that Davis is the mainstream way to go. But things like to use a ultrasonic wind anemometer is nice. But really as far as i can see all instruments need to be setup in exactly the right way to get the optimum performqance.

I am wondering if a "weather Station" is the right to go or if separate instruments are more ideal.

I am looking for optimal, not cost or convenience savings.

But open to all ideas since i am new to this - so therefore rule nothing out at this stage

Regards

J.B

[johnd]

I am wondering if a "weather Station" is the right to go or if separate instruments are more ideal.

'Weather station' simply means a set of instruments or sensors that are installed to measure weather conditions - there's no implication as to whether the sensors are clustered into composite assemblies or not and indeed many weather stations are based around individual sensors/instruments.

And I think that you're slightly confusing how standardised the readings will be with the quality of the sensors. So the WMO (World Meteorological Organisation) suggest that wind data are measured at 10m, temp/hum data at 1.2m and rain data essentially at ground level (and, additionally, with extra criteria as to the openness or exposure of the sensors). But the sole purpose of these suggestions is to allow readings to be validly compared between different locations, since they've all been measured under agreed standard conditions. But in practice it can be tricky to meet all of these criteria, especially a 10m height in a well-exposed location for the anemometer and so private stations often have sensors with non-standard exposures.

If you particularly want an ultrasonic anemometer then this can be purchased as a third-party add-on to a Davis VP2 station, using an LCJ model. If I was basing a separates station around the Davis architecture then I'd probably suggest:

Davis 6382 T/H supplementary transmitter
Davis 6312 VP2 console and Weatherlink logger
LCJ Ultrasonic anemometer with builr-in solar PSU
EML Kalyx rain gauge

[Jim Beam]

Thanks for the info and heads up JohnD

Much appreciated.


Rgds

J.D

[Jáchym]

If you want to be extremely accurate, you might also have a look at this:

https://www.wmo.int/pages/prog/gcos/documents/gruanmanuals/CIMO/CIMO_Guide-7th_Edition-2008.pdf

[Jim Beam]

It looks like Davis is a standard that has sprung up over the years.

Different instruments interface to Davis ports etc.

So, so far it seems like its best to not spit hairs and just use a Davis

Is that about the sum of it?

Thanks

[Jáchym]

I think Pro 2 Plus should be ok for you, it really is absolutely sufficient in terms of durability and accuracy. In our institute, we use extremely expensive Vaisala stations (when I say expensive I really mean it, eg. wind sensor on its own is around 7000) and basically the main reason these professional stations are so expensive is because they must be certified and calibrated each year and guaranteed to be accurate 100% of the time. However, they are as accurate as eg. Davis and Davis will also offer you highly accurate results, just that you will not have an annual certificate for it and it might not be 100%, but say 99.999% of the time.

[Old Tele man]

ANALOGY: Consider a home weather station as being analogous to home stereo gear:

• ALL-in-ONE = Integrated Weather Station = Integrated Stereo, ie: everything is contained in single enclosure.
• SEPARATES = Component Weather Station = Component Stereo, ie: separate CD, turntable, AM/FM receiver, amplifier, etc,.

PROS & CONS:

• INTEGRATED = when one thing fails, the whole system needs to serviced/repaired; but, no interconnection problems.
• COMPONENT = when something fails, only that item stops working, needing service/repair; sometimes part A doesn't interface with B, etc.

Your intended siting will most probably drive which system is best for you.

[Jáchym]

And of course separate sensors means you can site them better, if for example the solar and wind sensor are together with the temperature, you will never find an ideal place for it. You need to make sure you have very efficient solar shield for the temperature sensor and even then it is likely that at very hot and sunny days, it will be affected.

[CW2274]

You need to make sure you have very efficient solar shield for the temperature sensor and even then it is likely that at very hot and sunny days, it will be affected.

I respectfully disagree. A properly aspirated Davis 24hr FARS is as good as it gets without BIG money. I had ample proof of this this past summer.

[Jim Beam]

Interesting insights. Thank you for the comments.

Looks like there really is no reason to go beyond the Davis unit. 99% is good enough. This is for my own needs - no need for certificates and the like.

Is there any good resource for plans/ideas/hints on how to build a 10m (if i am going to do it, there is only one way....the right way) mast that can be tipped? I see from photos i have seen i will need to guy the pole down. How to go about home brewing that ? I live in the bush about 1100 Kilometers from the nearest major city where things can be got. This means i have plan everything out and procure everything i need to take up to the lake with me.

Also re the fan - i get that it can be replaced with something with more airflow and overall stronger - can it be run from 48v? Probably more correct to say, where can i get a suitable fan that runs on 48v DC. Rather not run 220v down to the waters edge if i can help it. Lightening is a huge factor here - we get massive amounts of it in our rainy season (which is starting now)

[Old Tele man]

Near water, consider LOW-voltage fans, 5VDC or 12VDC, readily available from MOUSER, ALLIED, etc..

[Jim Beam]

problem with 12v and especially 5v, is voltage drop over a few meters. 48v can have longer cable runs at lower amps, but i defer to the experts on how to do this.

[Maumelle Weather]

Hi and welcome to the forum,

On the pole, have you considered a telescoping flag pole? I have a 25ft. pole from here. They aren't exactly cheap, but they are 10 gauge thick walled aircraft aluminum. Somewhere on the site, it says the poles are good to 90MPH (144KPH).My pole has its base in a 24" x 12 diameter hole filled with 8 50 lbs bags of quickset concrete. It isn't going anywhere.

Just a suggestion,

John Sacrey

[johnd]

The standard fan motor runs off around 2v DC (depending on the charge state of the batteries and/or current sunshine levels). If you want to run off (much) higher voltage then you're going to need to find a physically compatible fan motor for yourself, which may or may not be straightforward.

If budget isn't an overriding factor then why not simply order up eg six spare standard Davis fan motors with the initial order? That should keep you going for 3-4 years.

[Jim Beam]

Info provided is great. Such a great resource here.

Which rain gauge/s should i be looking at ?

As per johnD's website, makes sense to use the rain gauge port on the Davis for other instruments (sun days for example) and use an external rain gauge.

JohnD.....excellent website, full of useful info. Very well done site.

[Jim Beam]

Re the Fan motor,

I think i would look into finding the right fan and just change it out at the get get go. Better performance and longevity. Sounds like the way to go. I dont want to be "down" and missing data because, sods law being sods law, the fan will go down while i am "in town" or even while i am off the continent on a trip somewhere. I think its better to just do it right out the gate and be done with it.

As for budget, well going the Davis route saves a wad  of $$$ compared to the higher end alternatives, so can now put that money into better quality instruments, such as the ultrasonic anemometer, sun days meter, rain gauge.

Also interested in lightening strike counting, location.  We get some MASSIVE lightening storms at times - truly awe inspiring to watch the lightening moving down the lake towards my site. Would be interesting to count these strikes in any given storm and how many stikes in the area overall per season.

[Jim Beam]

Flag pole is a great idea, but the shipping kills it. I will have to fabricate locally. Shouldn't be too hard to find a design that allows me to "dip" the pole so that i can work on/service the anemometer as/when needed. But then again, with an ultrasonic meter, is there any need to be able to get to it too often ?

[CW2274]

Re the Fan motor,

I think i would look into finding the right fan and just change it out at the get get go. Better performance and longevity. Sounds like the way to go.

80x20mm case fans are easily modded to fit into the VP2's sensor chamber. I and a few others here use them and they are superior to the stock motor not just in performance, but reliability as well.

[Jim Beam]

Re the Fan motor,

80x20mm case fans are easily modded to fit into the VP2's sensor chamber. I and a few others here use them and they are superior to the stock motor not just in performance, but reliability as well.

Thanks CW2274. I think this is the way to go. Beats messing with changing fans out periodically + better performance .....whats not to love? So i am with you on this.

[Jim Beam]

I am interested in a reasonably high end installation done right. I need wind direction and speed, solar irradiance , sunny days (for solar panel installation information) and rain information. Lightening information would be hugely interesting to me. Temp/RH is interesting but not essential for my needs

[Jáchym]

OK Jim,
I would really go for Davis Pro, look how many users of my template have it:
http://www.meteotemplate.com/web/users.php
It is that black "Davis" icon next to each user - I would say at least 60%. I myself would go for it without hesitation, the only reason I bought WH1080 was my budget.
For lightning you will need a separate sensor, as far as I know Davis does not offer this and I probably know only one station that does this, but there are separate sensors that measure it.