I sometimes use a double U bent into my support wire as shown.
Other times, I'll simply set my support wire with a single U. When it is where I want it, I'll break off a dead limb, and drive it tight into the hole for 5-6". This prevents most rotation. If you find a really good stob, and leave it somewhat long, you can use it to help narrow your pass-thru, and maybe disguise the support wire a little touch.
If I cannot push the support wire deep enough to suit me, I'll drive it. I made my driver out of an inexpensive fire poker. It's about 24" long, with one end swelling into a handle. The body of the poker is Ĺ" in diameter. I cut off the pointed end, and ground about a Ĺ" notch into that end. Finally, I ground a bevel around the notched point with a grinder, so it pushes into the ground easier. I have almost never had to actually drive this rod. I lock the support wire into the notch, and simply lean on the handle. The tool is one piece, with a hole bored thru the handle, so that the tool may be securred with a thong of some sort.