The sensors for my atmospheric observatory need to be mounted somewhere they can have unobstructed access to the sky and weather. The solution is a platform located away from buildings and trees.
The platform is built using the same materials and construction that one would use to build a deck for a house. For the legs I buried four 12 foot treated posts 2 foot into the ground with concrete around them. Then I build a 4 foot square platform at the top and added a hand rail. It was a bit wobbly so I added some 1/2″ conduit for cross bracing.
The platform needs a computer to gather data from all the sensors and relay it back to the house and then to the internet. To house the computer and any other support equipment I mounted a metal cabinet on the legs of the platform where it could be easily accessed from the ground.
The tower is roughly 14 feet to the top of the handrail. It needs a permanent ladder as I will probably have to go up and clean or adjust or repair sensors every day or so. Right now I use a piece of a magnesium extension ladder.
I debated with myself a long time about how to provide power to the sensors and computer. Solar power would have been fun but it would never be cost effective and I would have the extra hassle of maintaining the replacing the batteries. So I decided to to provide the tower with AC power by burying a cable from the house to the tower. That turned out to be a bigger project than I expected but it gave me an excuse to build a trenching bucket for my digger. That will be the subject of another post on my blog. Then about half way through the digging my digger got so lame I had to stop and repair it.
The cable run is too far for Ethernet so the data will be relayed back to the house by way of WiFi. You can see the directional antenna for the WiFi in the picture. There is a corresponding antenna attached to the house connected to a wireless access point device.
I installed an eight foot ground rod to ground the cabinet and electrical system for lightning protection and safety. The conduit for the ground wire is visible in the picture. The conduit for the power cable is behind one of the tower legs in this picture.
In the picture about I have dug about half of the trench and laid the cable in it. The digger is ready to go back and fill in the trench. It is not too obvious but the left axle is bent up. When I finished filling in the trench it was bent so badly that the center was dragging on the ground.
Going up to the house I had to cross the telephone cable which is marked with the red flags in the picture above. To do this without risking the telephone cable I used my DIY version of directional drilling. The trench stops just short of the cable on either side. I attached a garden hose fitting to a ten foot length of PVC water pipe and attached it to the hose. The soil in this area is quite sandy and with the water running it was easy to push the pipe from one side to the other. It took a couple of tries to get it to go straight and come out the other side. Once the pipe is through the power cable can be attached to the pipe and pulled back across the telephone cable.
A lot of people have told me that the tower looks like a deer stand. It is a bit close to the road to be legal for a deer stand. Hopefully when the sensors are installed people won’t think it is a deer stand. It got me to thinking that a commercial portable deer stand would make a good temporary sensor platform.