mast idea for new weather station

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[tom95521]

Hi,

I live along the coast in N. California and have just purchased a davis vp2 wireless weather station. I'm thinking about building my own mast that can be lowered when working on the wind sensors.

Last year in January we had 80 mph winds so it has to be fairly strong. I live in the country so beauty is not as important as functionality. When the mast is vertical it would be bolted to the two lower posts. I would set the posts in concrete with the mast plumb and oriented true north to make wind vane alignment easier. Estimated mast height would be higher than my house roof so it would be 4 to 6 meters when vertical.

Any positive/negative thoughts appreciated. Is there any reason to put the rain gauge/solar charger unit as high on the mast as the wind sensors? My design inspiration is the happy drinking bird that bobs up and down with their beak in a glass of water. 

Thanks,
Tom

[windy]

another way is a big L shape, with the hinge at the 90o angle
i.e when you want to lower it, you lift the pipe up thats lying along the ground....and walk in from one end...

[Kojack]

Any positive/negative thoughts appreciated. Is there any reason to put the rain gauge/solar charger unit as high on the mast as the wind sensors? My design inspiration is the happy drinking bird that bobs up and down with their beak in a glass of water. 

Thanks,
Tom

This is the "flagpole" design. With a metal mast (unlike the counterweighted drinking bird) It would be important to have the fulcrum as high as practically possible and some sort of rest/yoke to lower the mast onto which is roughly the same height as your pivot.

[administrator]

Here's a design for a tilt-over mast...http://www.wv7u.com/mast/mast.html. I think you can buy them ready made in the UK, so I'm sure you can get them in the US as well if you wanted avoid any engineering work.

[daveq]

I made the exact same for my Mother's purple martin house.  It will work fine for the weather vane but most likely you won't need to lower it very often.  Only caution is to have someone help you lower it as it will be top heavy as Kojack pointed out above.

The best place for the ISS is about 5-6' over grass.  Do a search for CWOP and look at their advice for positioning a weather station.

--Dave

[niko]

There's something like 40 feet of cable between the anemometer and the rain gauge and sensors assembly (ISS), so you could plan to install the anemometer at the top of the pole and the ISS on one of the support poles - then it wouldn't be affected by work on the anemometer. The rain gauge needs to be easily accessible for cleaning.

[Clanger]

Hi,
Nice idea Tom. I am going to have to look into this soon, already got some ideas. I have herd the VP2 wind sensors don't need a lot of maintenance unless there is a obvious problem.

[tom95521]

Thanks for the great ideas everyone.

I like the idea of mounting the iss low and just install the wind sensor at the top. I'm a little concerned about lightning with a steel mast (at least the iss unit is wireless), and rust is a big problem because of my proximity to the ocean.  I think a wood mast about 5 meters tall with the support posts 2 meters above ground would be about right.  If I make the mast much taller it will probably require a winch/pulley to raise and lower like the example tilt-over mast web page listed above.

I'm going to test the iss unit at the mast location and measure the davis vp2 signal % in various areas of the house (about 30 meters from mast) before building anything.

Tom

[Kojack]

Sounds like a standard flagpole would do it Tom.

You would have plenty of height but bear in mind solid wood is almost as heavy as metal tubing.

[tom95521]

After talking to a plumber at the parts store I have changed to a keep is simple stupid (kiss) design. It's a pipe inside a pipe. I can still lower the pipe, rotate to calibrate for true north anytime, and is probably much stronger. If you are wondering what purpose the 1.25" cap serves at the bottom of the hole inside the 2" pipe, it's to keep the 1.5" pipe from grinding down the concrete if the pipe is rotated. I have some stick grease (wax) that I can rub on the bottom of the 1.5" pole before inserting. No changing the design now. The 2" pipe is set in concrete. The 10'/3m pipe still needs to have the wind sensors bolted on. The wind sensor cable could be run inside the pipe, but I'm not going to do that until summer.

[Kojack]

Looks good and stable Tom.

[niko]

That'll work. I would have made the fixed pipe tall enough to take the ISS, but I don't think it makes much difference. Be interesting to see if you can really get the pipes apart after a couple of years...

[tom95521]

I'm almost finished with the install except for calibrating true north. I hope I can hang a plumb bob off the anemometer arm directly over the pole shadow at solar noon. All the set screws are stainless with lock nuts. There is silicone grease on all the threads so it should make it easier to dissasemble. I probably would have mounted the iss on the 2" pole if I had the right size U bolts. Total time about 4 hours (not including drawing the graphics or taking photos). There is also a galvanized cap on top of the 1.5" pole to keep the water out.

Thanks for the feedback.

[niko]

Looking good 

[Kojack]

Great work and clear illustrations Tom.
Beyond my DIY engineering skill