Here's the post verbatim...
"Hope it works and you can see my installation.
I used a piece of stainles angle plate and attach inside the hinge using existing bolt.
Extended post is not necessery, but it was used on previos antena that had top coil and I wanted the coil above roof line.
If you can find wider angle so the antena mount leg is further away from the door. Thats why I left the riser.
Also you can run the coax trough the gate, but do not try to feed it trough door wiring harnes, leave it on the outside.
I did that on my 08 and in the winter the coax got mangled inside the harness.