| It's only my opinion, but 'extending the posts' isn't likely to work out. You'd have to lay out some cash for metal brackets of some kind. And since the extra fence you add will be heavy, the brackets might bend and let the addition fall over. What you can do, though, is put up a second, taller fence just inside the outer fence. The second fence will act as a better sound barrier than just one higher fence ever could. The second fence can be butted right up to the first, or leave a buffer zone of three feet between them and hang up a sign, "Do Not Feed--Vicious Dog". Potential intruders will see what looks just like a dog run and think twice about climbing in. And hey, if you actually DO have dogs, think of this as the ideal exercise run for them. Dogs LOVE to run along fences and mark their territory. Two fences are twice as much fun. | 
