Topic: Okay, I admit it. I have a problem.....Radiation shield re-visited

[Likesspace]

As the title of this post says, I have a problem.
Although my home built, PVC monstrosity worked perfectly I have not been able to get it out of my head that I spent $35.00 on a SR-100 (that I'm not using) and have this ugly thing hanging on the side of my garage.
Well the result of these mental ponderings is that I once again re-thought my shield design.
Here's what I did.......
I used the SR100 as the base for this new FARS...
Picture the SR100 with a 6-1/4" long piece of 2" PVC pipe running vertically, straight through the middle of the shield.
I cut out an opening on the second solid plate and on the next to the bottom solid plate for the piece of pipe to fit into.
I also cut an 1-1/2" hole in the very bottom plate of the shield and mounted my PC power supply fan directly onto the bottom of the SR100.
The top of the 2" PVC pipe is exactly in the middle of the top and second plates of the shield.
The bottom of the 2" PVC pipe is butted up against the fan with the bottom plate between the pipe and the fan.
I ran 4 drywall screws into the PVC pipe (at the very bottom) to create a base for my sensor to sit on. I also took one of the circles that were cut out of the SR100 and drilled as many holes as possible into it.
The drilled circle was then ground down to slide into the 2" PVC pipe to give a non-abrasive surface for the shield to sit on. The drilled circle sits on the drywall screws and the sensor sits on the drilled circle.
What this setup allows is for air to be drawn into the top of the 2" PVC pipe and past the sensor inside.
The air is exhausted out of the bottom via the fan.
It should work exactly as the other monstrosity that I built but the setup looks a lot more appealing and I'm using the SR100 that I paid hard earned money for.
Looking at the SR100 you cannot tell that it is not stock but this should provide complete protection from solar heating.
The next thing I need to design is a solar panel/battery backup system so that I can stop using the 120 volt to 12 volt converter that I've been using.
If anyone sees any problems with this design, let me know, but all in all I'm pretty happy with how it has worked out so far.
By the way....I used a Rotozip to cut the holes in the SR100 but I'm sure that a dremel or similar device would work just as well.
If anyone needs to see pics of what I've done, let me know, but please.......only if necessary. I've had that SR100 apart so many times that just the thought of taking it back apart makes me cringe.
Even thought I wasted a little money on the PVC monstrosity, it gave me the idea to re-work the SR100. We'll just call that: Money well spent on R&D

Dave

[Likesspace]

Oh, one more thing....
Time spent was about an hour and a half, so this is a VERY easy project.
Also the money spent is very low (less than $10.00) even if a fan has to be purchased.
Hope this helps someone out.

Dave

[sam2004gp]

Pics of this setup?

[DanS]

Dave, sounds like you've got the right setup now. I went through similar experimenting and trying different FARS setups to see how I could track closer to an international airport 1/2 mile from here. My trials and experiments show great results with a setup like you're running with now. I then played with different fan positions and power sources. What I've ended up with, and still running with, is a shaded location and an un-aspirated shield that doesn't allow the sensor to "see" outside of it. That is, you can look from under the sides and not see the sensor from anywhere so it cannot "see" out to reflected sunlight. There are people who will tell you that the shield has to be in direct sunlight to be accurate but mine is now tracking the airport and a nearby METAR source to less than 1/2 a degree Fahrenheit.
The way your running now should be the best setup if you have to be located in the sun. Good work!

Dan
 

[Likesspace]

Come on Sam....I said I didn't want to post any pics! 
Honestly, as much help as you've given me so far, it's the least that I can do.
Here's a couple of shots of the finished product.
If you need some pics of the shield broken down, just let me know. It will be tomorrow even before I can get to it but I will be more than happy to take the shield apart to show you what I did inside.
Okay, here's the pics.

Dave

[Likesspace]

Dan, thanks for the reply...
I've done some checking with this setup since getting it up and running and I'm pretty thrilled with the results...
I'm right in line with our local airport (within 1/2 a degree and I'm the lower reading) and with local PWS's which are also right on the money.
Also, after looking at my temp curve for the day it is nice and smooth with no spikes whatsoever. I think I've finally found the setup that works for me.
The fact that it looks nice is just an added bonus since my "u-bend" set up did work fine. I just can't handle having something that looks home made and out of place when there's a better solution.
As I said before, now I just have to figure out the solar setup to make this wireless. I'm still not thrilled with having the wires strung across the side of the garage.
I can (and will ) make it look better by running the wires in conduit if I can't figure out a wireless solar solution, but this was a quick test so it doens't look as good as I'd like for it to.
Anyway, thanks again for the reply and have a great weekend.

Dave

[Strgazr27]

Dave,

See this thread http://www.wxforum.net/index.php?topic=4698.0 for an idea. I ordered this one here http://www.goldmine-elec-products.com/prodinfo.asp?number=G17171 for my FARS and I'm hoping to install it in the next 2 weeks or so.

Bobby

[DanS]

... here's some more panel/fan info as well, Dave. Have fun.  

http://www.wxforum.net/index.php?topic=3732.30
http://www.wxforum.net/index.php?topic=3651.0

[Downlinerz2]

    Thanks Dave and Bobby,
    I think this setup is going to solve my problems.  I have been looking for an easy to do FARS mod and I think I can even do this( ).  I ordered the solar panel power unit just a few minutes ago.  I only need the fan to run during the day when the Sun is shining so this unit looks perfect!!!
    Thanks guys!!!!  Happy Days Are Here Again!!!!
               Mark

[Likesspace]

First off, thanks to everyone for the information on solar power. That was very interesting reading.
Mark......
One word of warning:
On my other setup up (what I call the monstrosity) I had some serious high reading problems if the fan was not running, even during the evening hours.
With the sensor inside a piece of PVC pipe, there is NO air movement and I would read about 3 - 4 degrees higher than another sensor that was positioned only a few feet away.
I've found that the only way to see accurate readings is to have the fan running 24 hours a day, which can certainly be solved with a solar/battery backup system.
For my part, I've decided to keep my system as it is.
With the station mounted to my garage, I have easy access to a power source and the expense to run the fan is negligible.
I've decided that I will run the wiring in a conduit which should look just fine one it is finished.
Although the solar project sounds like a blast, I have one daughter in college and another a year away from college. Right now, every dollar counts!
Mark, this really is a simple project, but I do belive that the fan would need to run 24/7. If you have ready access to a power source it should be a piece of cake and only marginally more difficult if you need to use a solar setup.
Please let us know how it works out for you!
Again, thanks to everyone for the information. Down the road I can see a lot of play time coming with solar panels and battery chargers.

Dave

[Likesspace]

In case anyone is interested in seeing how this setup works, here is a link to my temperature chart on Weather Undergound.
The spike at 4:10 is when I took the sensor out of the monstrosity and mounted it into the SR100. Other than that one spike, I'm really happy with how smooth the temp curves looks, especially for a $120.00 weather station. Before 4:00 is the curve for my u-bend monstrosity....after 4:00 is the modified SR100. To me the curves look really similar and quite smooth.
Anyway, here's the link: http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KILIUKA2

Dave

[Likesspace]

.....As a comparison, here is the link to a nearby neighbor's station running a Davis VP2:
http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KILALMA1
As you can see, it is possible to get really good readings even with an inferior station. I just wish I felt confident about the longevity of my hardware as compared to the Davis.

Dave

[Downlinerz2]

Dave,
   Thank you.  I will take your advice and run the unit 24/7.  Will decide exactly how I will do that after I check a few things out.  I am not very electrically savvy so I will get advice from an electrician friend.  Thanks again for the good advice!!
        Have a great weekend holiday!!
                  Mark

[Downlinerz2]

Dave,
  Can you tell me the reason for the vertical 2" P"VC?  Why can't holes be drilled in the bottom plate and attach the fan there and keeping the sensor attached at the top on the vertical rod?  I know there is a good reason but I can't quite reach it . I appreciate your help.  I cannot wait to do this mod.
        Mark

[Likesspace]

Mark,
First of all, I really apologize for not replying to your post before this. Honestly, I just now saw that you had asked a question...
The reason for the vertical PVC pipe is to keep ALL sunlight from hitting the temp sensor.
Even with the Ambient shield I was still having a problem with the sun heating the sensor. Even though the plates overlap each other, I was getting heating from reflected light off of the ground (at least I think that's what was happening).
With the vertical pipe, there is no way in which sunlight can get to the temp sensor. It is completely in the dark at all times and this seems to have solved all of my problems.
I've had this setup for right at a month now and I haven't given my temp problems a thought in that time.
I would recommend this modification to anyone after having tested it out. I still run within a half of a degree of my local airport and am usually the lowest temp of every other PWS around me.
Again, I'm sorry for the delay in answering your question.
Hopefully this information will still help you out.

Dave

[Downlinerz2]

Dave,
  No problem with the delay.  The question became a mute point about 3 weeks ago when I bought a new Davis station. I will still be keeping this FARS mod on file because I may still use the WMR968 in the future.  I have even collected much of the materials for it including a computer fan that comes with it's own solar panel.
Thanks for the info.  I was thinking it was something along that line. 
       Mark