Several weeks ago, I installed an NMO scanner antenna on my car using an L-bracket. It looked something like this:
It looked ok, but after some reading I found that for the best performance, mounting the antenna centered on the trunklid would be the way to go. So I read up on the process and found it simple. I bought a 3/4" hole saw at the local hardware store and set about getting the job done. After eyeballing the site on top of the trunklid where I wished the antenna to go, I opened up the trunk.
Next I removed the carpet soundproofing (?) to see what I would be drilling into. My primary concern was avoiding the wiring for the back-up lights.
The wiring (upper left) is well clear of where I want to drill, but there is that hump in the way. I quickly decided that I'll drill using the top hole as a guide and thread the cable through the opening near the top of the photo. I'll have just enough room to get my hands in that opening to manipulate the inside portion of the NMO mount. The next step was to drill the pilot hole through the underside of the trunklid.
X marks the spot:
The hole is further back than I wanted, but it will still work. This area is still flat enough to not introduce any gaps between the exterior portion of the mount and the top of the trunklid.
Drilling was accomplished without any trouble or explosions. I used a magnet to pick up the metal bits and removed the frog tape. Next, I threaded the cable & mount assembly through the hole and reattached the ring nut. While easy, this portion was a bit awkward due to the Milan's trunk design. Needlenose pliers in my left hand, holding the bottom portion of the NMO mount in place while holding a wrench in my right, tightening the nut on the top of the trunklid and I can't see anything due to the trunk's lip. Even so, the process was completed quickly.
In addition to the Larsen NMO150/450/800, I also have a Laird Tech QWFT120:
Before sending the cable through to the interior of the car and re-installing the carpet, I connected the scanner for a quick test to make sure that all was well. After a few transmissions, I was happy and pulled the car back into the garage to finish up the install.
The wiring for the back-up lights provided a great path to route the antenna cable:
After routing the cable though the back seat and up to the front passenger seat, it still makes the conntection to the scanner with plenty of slack still available:
To mount the scanner, I bought a basic cell phone holder at Wal-Mart. The bracket wasn't all that great (the scanner had a tendency to "wiggle" out of it), but the package contained a piece of thin, flexible metal that easily slides into the gap on the cup holder "door" in the center console and attaches to the scanner with a couple of pieces of 3M Dual Lock fasteners.
Not the most elegant solution, but better than just laying the scanner on the passenger seat (can't see the display all that well) or laying it atop the cup hold "door" (slid off to easily).
Preliminary testing (i.e. cursing around town) with the Larsen antenna shows that reception is at least on par with the previous L-bracket mounting. While the primary purpose of all this was to improve reception, I'm still happy with the end result as the install looks better.