Never pulled cable, but my subsoiler (cheap one from NorthernTool) will drop in a foot to 18". Puts a good load on my L3200, but a smaller tractor could probably pull it in reasonable ground. If not, try multiple passes dropping deeper each time. Sharpening the vertical bar might help a bit too.
i live on an island which is all rock, roots, and dirt. I am putting in
about 1000 of power and water lines as well as 4 drain pipe. Frost is not a problem. I知 looking at Bro-tek ripper/trencher combo or Tractor attachments trencher bucket. After finishing my own work I can get a ton of work with the local water district. I知 looking for an efficient well made tool for my BX23s.