Installing antennas on vehicles with aluminum body panels presents a few challenges, including galvanic corrosion. One of the most common situations in the two-way radio world as of the writing of this post is installing a radio in Ford’s F-Series pick-ups, however other models and other manufactures also utilize the weight savings of aluminum. A least in the case of the F-Series pickups, there are solutions for fender mounts and magnetic mounts.
For our purposes here, we’ll focus on Ford F-Series trucks, although the principles should apply to most aluminum body vehicles.
Before digging into solutions, we strongly recommend you familiarize yourself with Ford’s SVE-Q-222R1 Bulletin, “Attaching Accessories to Aluminum Panels and Structure.” A link to the document has been provided below. You may find other bulletins of interest as well.
We have included a copy of the Ford SVE-Q-222R1 Bulletin for your convenience. To be clear, this is a Ford document and we strongly recommend getting the latest version from their site to ensure you have the latest version.
If the client requires the antenna to be mounted on the roof (or trunk lid if a sedan), it is important to follow the procedures laid out by the vehicle manufacture to prevent corrosion. Be advised that most NMO cable kits assume metal to metal contact is permissible. The installer will have to provide the necessary galvanic isolation. Anecdotally, there are few problems as long as care is exercised, however, if it’s not your own vehicle you might consider opting for a fender mount instead.
Installing an antenna using a fender mount is much simpler. For Ford F-Series truck, you will likely need a West Mobile Mounts ATFO11LD or ATFO17HD bracket (driver and passenger side are available). Be sure to use the existing fender bolt with the washers recommended in the Q-222R1 bulletin. Do not add any screws as per the bulletin.
Yes, you can mount a mag-mount on an aluminum vehicle…with a little help from one of these. Essentially it’s a steel plate with high a high strength adhesive pad on the bottom. Once attached to the vehicle a standard magnetic mount can be used. We stock both the ATDISC3.5 (3.5in) and ATDISC5 (5″) pads from West Mobile Mounts.
A word of caution, do not expect to remove these adhesive pads. Trying to remove them may damage the vehicle.
One last thought on using the mag-mount pads, while there will be capacitive coupling through the pad to the vehicle body, it may be advantageous to use a 1/2 wave antenna. They tend to be less impacted by ground plane characteristics. As expected, models specifically designed as “No Ground Plane” required or “Ground Plane Independent” antennas may give more predictable performance.