How to: Build a cool tool.

God I was hoping you would put some kind of disclaimer, I could just see somebody doing that and then blaming you for getting them fired!

We have several of those ground antenna's at work we pulled off of customers cars when they got replacements.  They do work great.

I bought a magnetic tool tray I purchased at Harbor Freight and really never use it.  I usually just use the factory cup holders/cubbies to hold the factory screws.

You can make your own perfect circle using a piece of plexiglass and a plunge router.  Just cut the plexiglass so it will mount on the router.  Now when you need to cut a circle, just use a tape measure to measure from the router bit to the circle radius you desire, and mark this point with a sharpie.  Now drill a hole through the plexiglass and into the center point of the desired hole, but don't take the drill bit out of the wood/plexiglass.  Instead release it from your drill, and it will act as a pivot point for your router. 

Like I say, great Steve's think alike.

I can't take credit for that though.  It was taught to me a long time ago by an installer I used to work with.