Barbed Wire Chain Link Fence Height

That would be 5 scale feet. Chain link fence comes in a variety of heights, ranging from 3 feet, (3/4") in the o scale world, on up to twelve feet or more. Most common size is four foot for most residences. Many industrial fencing is usually 6 feet or higher. The barbed wire would add about another six inches.

At a 1/4" per foot (1/48 scale), 2-1/4" figures out to be 9 scale feet.  8 feet of chain link plus another 1 foot of barbed wire sounds reasonable to me.  I believe prototype chain link is most likely available in 8' width rolls, amongst other widths.

On farm we bought 7FT poles, at 48" to get below frost line gave us 5 ' average height in the poles, the wire started about 6" below top. Barb wire fences don't need a 6 foot height and never seen that height. Be sure the wires are on the inside of what you want to pen or keep from going through. For cattle we usually had 2 strands, but if smaller animals, goats, etc. we would have 3 strands.

Horse owner very rarely would use barb wire fences, in fact we never pastured our horses in a barb wire pasture. Rarely ever saw a barb wire fence above 5 feet. Hope that helps.

OOps. my error. I see you want barb wire on top of a chain link fence. I have one in back yard separating my land from a preserve. The fence is 6' and the barb wire are 2 strands angled outward at a 45 degree angle added top to fence post. Sorry for error.

Standard industrial fences are eight feet high(2 inches) to the top rail. I add another half inch to the pole height to accommodate the barbed wire. You can bend the top of the post on an angle also.

16' + a roll of concertina on top around a place I worked on Okinawa.  Also had full time security lights, guard shacks at the gates and roving patrols between sundown and sunrise.  Total protected area was only about four acres.

Thanks for the tips guys!  It sounds like I'm on the right track with my measurements from what I gathered from the comments.  I'm always trying to learn more and better my skills when it comes to modeling, so I really appreciate all of you guys help!