Step 1: Materials and Tools
2 x 10' 1/2" copper pipe ($13)
4 x 45 degree1/2" copper elbows ($1-$2)
2 x 1/2" copper T's ($1-$2)
2 x 20' copper wire. I used 12 ga wire left overs, but I saw 25' of romex was about $10 at the store. Bonus if you don't have to strip the wires - it's kind of a pain to strip 20'.
Soldering equipment - torch, solder, flux - see http://www.google.com/search?hl=en&q=how%20to%20solder%20copper%20pipes
Drill or drill press
Step 2: Laying Out, Cutting, Dry Fitting
I cut the 12", 2 x 6", and 2 x 30" first. Then I measured and cut the 21 1/4". The 24" base will be driven into the ground. It's probably more than is necessary, but I had a lot of pipe available.
Once everything fits the way you want it, it's time to drill the holes for the wire.
Step 3: Drilling the Holes
Copper's very soft. I just used a standard bit, just big enough for my wire to fit through, and went slow.
Once the holes are drilled, it's time to solder.
Step 4: Soldering
In order to keep everything square, I fit the whole thing together again and laid it out on my concrete floor. Warning, this may stain the floor a bit. If you're one of those people that can't stain your garage floor (hi Dad!), seek help.
Once laid out, I simply went around and soldered each joint in turn. I find that you can't apply flux that well when the pipe is hot, so I would sort of alternate between opposite joints, looking for a cool section to solder.
I suggest leaving the bottom two pipes that will be buried unsoldered.
Step 5: Wiring
The first step is to strip it from its outer sheath. I ended up with one long uninsulated wire (the ground), and two insulated wires. I calculated that I needed about 20' for the horizontal runs, and 10' for the vertical runs. So I used the uninsulated for the horizontal, so that there was less to strip.
Simply, I terminated the wires by neatly wrapping it around the post a few times. I considered soldering it in place, but I didn't see the need.
I wasn't able to get the lengths of wires as tight as I would have liked. Perhaps someone has a better idea :)
Step 6: Installing
That's it! If you do something like this, post a link to the pictures here so I can see the variations :)