I found a guy on ebay and emailed him your question. He states the outer diameter of the conductor is "right around 3/16". Personally it sounds like a guesstimate. If these dimensions are critical it would be my suggestion to do the measurements yourself. The old measure twice, cut once adage...
I didn't run across any information on the web that gave the particulars, but seeing as you're going to have the cable in your hands, why not just measure the diameter with a caliper?