Thanks for replying Anole.  It is a 30" dish with a motorized mount.  The block wall is a chimney.  When I bought my house it came with a smaller, pay per month, chimney mounted dish (DirecTV).  I've never used it and would like to replace it with the FTA system I just bought.  I'm also wondering if I need to install new wiring or can I use the cable connecting the current dish.  I'm not sure what you mean by "support struts."  The mast is attached to something called a "mounting foot."