Couple of years ago me and Jakke where conducting some lightning measurements. We were in a hurry and on a budget. Well, perhaps not so much on a budget as I was (and am) fond of cheap solutions. What we came up with, was a way of using some 50 mm by 50 mm sawn softwood (likely spruce or pine), some plywood and a couple of polypropylene buckets to make a fairly durable weather cover. These could be used for example as part of an open monitoring project.
Since I’m lazy, I didn’t bother to dismantle them after the measurements ended and a couple of these have been out in the weather (Southern Finland) for about four years. Today I finally decided to take them a part. I found out that they have been holding up pretty well and would likely have been up to their task for at least a few more years. So if you are looking for a way of making a similar system, below I explain how to make them. At the end are a couple of pics and comments on the dismantled set.
White buckets were used in an attempt to keep the electronics cool. Other colors may be used depending on location to make it less visible.
Figure 1 shows a rendering of the two ways we used to setup the systems. In the left the stud is driven to the ground. I used an iron bar to first make pilot hole and then carefully using a small piece of plywood as protection (between the sledge hammer and the pillar) hammered the stud to the ground.
In the right is the system we used on a (Melbourne) Florida roof top for a couple of months to create a more temporary measurement setup. We used some concrete blocks as additional weight just in case. If you are considering a more permanent system consider adding some steel wire to attach the system to something really heavy. You don’t want it hitting someone when it is picked up by hurricane winds or a tornado.
Figure 2 shows what you need. All sizes are approximately those we used, select your bucket size to match the size of your device and scale everything else accordingly.
- Two short pieces of wood. One should be short enough to fit side ways in to the bucket and one should be about 5 cm shorter than the bucket is high. One long piece of wood, it will determine how high the rest of the system sits.
- A piece of plywood, cut a circle that fits in to the bucket to a depth of about 5 cm
- Two buckets
- Some screws and hot glue
- a saw, (sledge)hammer, screwdriver, eye protection etc.
As shown in Figure 3 set the longer of the two short pieces of wood on top of the plywood. Use hot glue or two screws or both to attach it in a manner that it can’t rotate around the vertical axis. Before this, make any openings you need for electrical wiring and such.
The shorter piece of wood is then attached on the other side of the plywood. Select the correct length for the support pillar and after driving it to the ground attach the plywood to it. If any of the wood surfaces is curved using copious amounts of hot glue between surfaces before inserting the screws will make the system more solid. The inner bucket is attached with one screw, which is driven through the bucket bottom to the piece of wood shown in Figure 3. Note that you will be driving the screw in the direction of the grain, do it carefully or the strength of the attachment will be reduced.
Add the other bucket, this one stays in place by gravity and friction. If you use a screw, rain will seep in.
Figure 4 shows the support structure and the weak point at the air-ground interface. Rotting has reduced the strength of the wood. If the place where measurement are taken is not very sensitive, consider using wood that has been treated to protect against rot. Using a larger size like 75×75 or even 100×100 mm2 will likely also give you a couple more years of service life.
