Someone sent me some coils for evaluation, and they were of little value, due to lack of attention to detail. A coil does not have to be perfectly smoothly proportioned and a work of art to work fairly well; some of my funkier coils are a bit uneven in spots. But if too sloppy, coil-making is a waste of time.
Here is an example of the sloppiest coil I would still consider using for cheaper units. You can see that it's uneven in spots. Very seldom do I make one this bad anymore. But it still feels more or less OK.
I made up some demonstration coils here:
Above are two worthless coils on the left, and a good one on the right.
The worst error, energetically, is that the tops are scrunched inward. This can easily happen when making jerrified cat coils out of heavy gauge wire. It is easier to repair early in the process, rather than afterwards.
Notice how this one to the right has its top domed in the same direction as the body? It can even be flat on top, where that fits better into what you're making. But not concave.
OK, now another thing that wants to happen when you make a significantly catted coil is that the ends tend to go back toward the body of the coil, as you can see to the left. Much of a coil's energy goes out the tips, and as covered in the coil info page, one can manipulate the tips to make the coil do different things. But generally, I don't like the effect when the ends are left as depicted in the bad coils. You see in the good version how I believe energy generally flows best.
Incidentally, the energy direction of these depicted coils is predominantly toward the base. Do not copy this coil if you want more energy to go toward the tip; reverse the direction of the wind.
Loohan