HUNTING WILD BOAR AND TRAPPING FERAL HOGS INFORMATION
Here are the materials you will need to make a hog snare.
10 feet of 1/8" galv aircraft cable. one 1/8" Berkshire extra heavy duty lock. Two single ferrules (stops). One double ferrule. One Wammy (homemade).
You will need these tools.
Cable cutters. Needle nose pliers. Hammer. Bolt cutters with the jaws ground down for a swagging tool.
The most important thing to remember when making any type of snare is to work with the natural memory of the cable. Placing the lock on the cable, making sure the memory is proper.
While holding the snare loop vertical I place a stop on the end and give it a few wacks with the hammer.
With the needle nose pliers I then make a reverse bend in the cable.

Here is the lock end complete, except for the deer stop.
If you'll notice in the last pic the loop is tear dropped. Using the crank handle on the vise I load the last 4-5 inches of the cable by the lock. This makes the loop stay round but more importantly is it makes the snare "fire" shut.
When loading the cable it is very important to make sure you load it with the natural memory of the cable or the loop will want to form a figure eight. 
After loading.

All thats left is to rig the anchor end. The one shown is an adjustable end. It can be a fixed end by just using a double ferrule.

If I'm going to be snaring where deer are present, I'll add a deer stop so the loop will not close tighter than 3" dia. For deer stops I use those small stainless steel hog nose rings used in making crawfish traps.