I recently constructed a 3-metre (9-foot) gate for the entrance to a laneway at the back of my place and after I'd mounted it, first thing I noticed was how "wobbly" it was. I had put braces on it (a series of braces running the length of the gate, rather than just one diagonal piece in the middle) and the post seems to be pretty sturdy, although it was sunk originally for a lighter-weight gate. The gate also sags on the latch side - I tried the "sagging gate" solution using cable and a turnbuckle, but that made no difference. The gate is heavy, and I mean heavy - and I mounted the pickets on 3 rails rather than the usual 2.
Anyone have any ideas as to what the problem might be with both the wobbles and sag? I spent quite a bit of time building this gate and I'd really like to get it fixed and working.