Mobile Weather Stations

[Brett Adair]

I know I know....look back at other threads. Well, I have searched and I can not find exactly what I want to see. I am looking for the PVC built mobile stations. I don't have the tools to build an aluminum based station and I have just acquired a Radioshack WX-200 to use as a mobile station so I need to see some models of PVC stations that you guys have built. I know I have to build a fan aspirated pipe for my hydro/thermo sensor so I don't know exactly how that would work with a PVC system. Any help is appreciated. Thanks!

 

[Joey Ketcham]

I know I know....look back at other threads. Well, I have searched and I can not find exactly what I want to see. I am looking for the PVC built mobile stations. I don't have the tools to build an aluminum based station and I have just acquired a Radioshack WX-200 to use as a mobile station so I need to see some models of PVC stations that you guys have built. I know I have to build a fan aspirated pipe for my hydro/thermo sensor so I don't know exactly how that would work with a PVC system. Any help is appreciated. Thanks!

Brett, you might email Tyler and ask about the one he has... it's PVC and think it's along the lines of what you're wanting.. but I won't swear by that.

 

[JR Hehnly]

You might try this paper:
http://ams.allenpress.com/archive/1520-0426/13/5/pdf/i1520-0426-13-5-921.pdf

 

[John Diel]

I'm not a big fan of the PVC pipe based construction. It's light, and relatively easy to put together, yes, but they also tend to be less aerodynamic in they catch a lot of wind and even some of the best anchoring will loosen up in constant high winds.

That being said. It has been done. I think Chris Collura has a decent explanation on is web site (you'll have to look it up though. Sorry). You could always go with the aluminum railing available at most Home Depot's or Lowes and simply bolt it together with lock washers.

As far as the Radiation Shield goes, what I did was use 4 in PVC pipe with a 90 degree turn at the top, and about a 4 inch length there terminating with a size change from the 4 inch to 3 inch and a 4 inch cap on that. The cap was held with 4 screws and had about 1/2 inch clearance to allow air movement. Now I got a little fancy and made it Fan Aspriated by mounting a 12 Volf DC fan in the top and using it only when stationary to keep the air flowing.

The sendor brick was suspended in the vertical tube midway of the 14 inch length. I used 4 long screws to center the brick and keep it from touching the inside tube. The wires (I had a wired Davis Station) exited the tube via a hole that I drilled and sealed with silicon once the wires were threaded. The bottom terminated in a 45 degree down angle with an additional 3 inch pipe cut to angle and left open for better air movement. Both ends had standard porch screen cut to fit to keep the local critters from taking up residence inside the tube (Birds and spiders love this kind of thing).

The whole array along with the anemometer and vane was then mounted to and old photographic monopod I had laying around which allowed about 24 inches of telescoping. When out on the chase, I could put the thing up to height which placed the anemometer out of the Bernoulli Effect and when done and in town, set it back down to a reasonable distance that kept it out of tree branches and let me get under fast food canopies.

It was small and reasonably well contained and could be taken down in 10 minutes (pulling off the U-Bolts that held it to a mounting rod). The readings were accurate to +/- 1 degree when checked against both local NWS airfield METARs and a sling psychrometer.

It survived several Meadowlark strikes and 3 inch hail with out a burp. The only problem I had was that birds liked to sit on the anemometer arm and tended to crap on the cups and truck.

I'm saving now for one of the "Ultrasonic" stations that are GPS enabled. Supposedly they will calculate your speed and direction to give you "true" wind speed and direction relative to your motion. In reality? I've heard it's semi-accurate. They're primarly made for marine use (sailboats) which move much slower than your average chaser and certainly don't get into 90+ mph winds unless they are extremely unlucky along the Gulf Coast!

 

[Brett Adair]

I'm not a big fan of the PVC pipe based construction. It's light, and relatively easy to put together, yes, but they also tend to be less aerodynamic in they catch a lot of wind and even some of the best anchoring will loosen up in constant high winds.

That being said. It has been done. I think Chris Collura has a decent explanation on is web site (you'll have to look it up though. Sorry). You could always go with the aluminum railing available at most Home Depot's or Lowes and simply bolt it together with lock washers.

As far as the Radiation Shield goes, what I did was use 4 in PVC pipe with a 90 degree turn at the top, and about a 4 inch length there terminating with a size change from the 4 inch to 3 inch and a 4 inch cap on that. The cap was held with 4 screws and had about 1/2 inch clearance to allow air movement. Now I got a little fancy and made it Fan Aspriated by mounting a 12 Volf DC fan in the top and using it only when stationary to keep the air flowing.

The sendor brick was suspended in the vertical tube midway of the 14 inch length. I used 4 long screws to center the brick and keep it from touching the inside tube. The wires (I had a wired Davis Station) exited the tube via a hole that I drilled and sealed with silicon once the wires were threaded. The bottom terminated in a 45 degree down angle with an additional 3 inch pipe cut to angle and left open for better air movement. Both ends had standard porch screen cut to fit to keep the local critters from taking up residence inside the tube (Birds and spiders love this kind of thing).

The whole array along with the anemometer and vane was then mounted to and old photographic monopod I had laying around which allowed about 24 inches of telescoping. When out on the chase, I could put the thing up to height which placed the anemometer out of the Bernoulli Effect and when done and in town, set it back down to a reasonable distance that kept it out of tree branches and let me get under fast food canopies.

It was small and reasonably well contained and could be taken down in 10 minutes (pulling off the U-Bolts that held it to a mounting rod). The readings were accurate to +/- 1 degree when checked against both local NWS airfield METARs and a sling psychrometer.

It survived several Meadowlark strikes and 3 inch hail with out a burp. The only problem I had was that birds liked to sit on the anemometer arm and tended to crap on the cups and truck.

I'm saving now for one of the "Ultrasonic" stations that are GPS enabled. Supposedly they will calculate your speed and direction to give you "true" wind speed and direction relative to your motion. In reality? I've heard it's semi-accurate. They're primarly made for marine use (sailboats) which move much slower than your average chaser and certainly don't get into 90+ mph winds unless they are extremely unlucky along the Gulf Coast!

Have any photos of your station?

 

[John Diel]

Unfortunately, not any worth looking at. However, going over the PDF posted above. My setup was very similar to this set up. Other than using a little larger pipe and a different sensor array, it's pretty much identical.

Rather than mounting like the mobile mesonets had, I stayed with a single mast with the Temp/humidity sensor in the radiation shield and the anemometer/wind vane another 6 inches above that. Of course I wasn't using RM Young or Viaisla equipment either.

Here's a picture of the truck with the mast up. http://www.pbase.com/okie34/image/31035542 The Radiation Shield isn't mounted yet as I was still designing the interior. However, simply add to that one of the radiation shields you see pictured in the pdf posted above and and you will get a sense of what I had working.

This truck is no retired and my "new" vehicle does not have a station. Other than wind speed, it really isn't a necessary item. An anemometer would be helpful in estimating wind speeds and certainly remove the guess factor from my reports. The other instruments were helpful in finding the dryline rapidly, but as time goes on anyone with two good eyes could find it.

It was nice to look at and watch the conditions change as storms moved through, but did it help my chasing any? No. Did it help anyone else or research? No. Was it fun? Yes.