About Magnet Mounts
Magnet mounts offer a convenient method of
installing an antenna on a vehicle. The magnetic mount antennas also give you
an alternative choice instead of drilling a hole in the roof of your vehicle,
especially if the use is only for vacation, temporary use or portability is
required of a communications system. However, there are some considerations
that should be noted.
- Magnet mount antennas actually get their
ground through capacitive coupling with the metal of the vehicle. The
capacitance that the magnet forms with the surface of the vehicle is what
couples the RF circuit to the body of the car. It determines the
efficiency of your antenna installation.
- When removing the magnetic mount from the
vehicle, do not slide it across the roof or surface. This may make it
easier to get to and remove, but the dirt and metal particles on the roof
will leave scratches on the paint from the sliding action. It is best to
grab the coil and tilt it towards you to easier break the bond that the
magnet has with the metal surface of the vehicle. As this bond is broken,
you can then lift it from the installation position.
- Do not leave the mount in one location
for extended periods of time. The vehicle paint will discolor and moisture
under the mount can cause rust to form on or under the painted surface.
Periodically remove the mount and clean both the mount and the area it is
on to prevent this. If you live on the coast or in an area where there you
receive a lot of rain or snow, this should be performed about every 3-4
months. Dryer climates can do the cleaning every 6 months (in the fall and
- The damage to the surface of the vehicle
can be lessened with the use of a thin material between the magnet mount and
the surface. A recommended item to use is nylon. This can be from a pair
of ladies nylon panty hose cut into a circle about 1/4 to 1/2" larger
than the diameter of the magnet mount.
- Beware that if you are using a high power
amplifier, the probability that heat will discolor the vehicles paint is
greatly increased. The higher the power, the sooner (and more severe) this
will occur. Using high power will require more attention to the finish of
the roof and movement of the mount.
- Pay particular attention to the routing
of the coax cable, watching doors and windows for coax pinching.
Continuous slamming the door or raising the window to hard on the coax
cable will weaken it and cause the center conductor to break.
- If corrosion or rust sets up inside the
magnet mount, the magnet may come loose from plate. If this occurs, the
antenna may be separated from the magnet (which may stay on the surface of
the vehicle) when the antenna is removed. The best way to remove the bare
magnet from the surface is with the use of a large pair of channel lock
(aka water pump) type pliers. Expand the pliers to the largest opening,
grasp the magnet from the center hole to the outer edge between the teeth.
Carefully, yet forcefully, lift as you tilt back the pliers. This will cause
the bond to loosen and break allowing you to remove the magnet from the
surface. The mount can now be repaired or replaced.
- How do I repair this separation?
NOTE: Refer to magnet mount assembly for location of all parts.
The following steps should be done outside, in the garage or other well
- A. Clean all surfaces with a small steel
toothbrush type brush.
- B. Use a cleaning solution that will
dissolve rust and corrosion. A good example is the pink type of
Navel Jelly. Follow the directions on the label for best results.
- C. Allow all parts time to completely dry.
- D. Place magnet on newspaper or cloth.
- E. Mix a 2-part solution of epoxy.
- F. Run a 1/4" to 3/8" bead around
the center of the "donut" of the magnet.(see
illustration to the right).
- Place the bead of epoxy
as shown above
- G. Holding the metal plate by the outer edges,
carefully align the plate above the magnet, without
- H. Slowly lower the plate towards the magnet.
CAUTION: Watch fingers - as you lower the plate, the pull
of the magnet will become increasingly stronger to a point that the magnet will
quickly pull the plate onto it with a loud snap.
- I. After the plate is attached to the
magnet, carefully slide and align the two pieces so they match.
- J. Watch for excess epoxy oozing from the center
and outer edges of the two joined pieces. Clean any
excess with a damp cloth.
- K. Allow magnet/plate assembly to dry overnight.
- L. Reassemble the magnet mount system
Note: It may be
neccessary to replace the 2 piece mylar protective covering (part number 880-500127) on the bottom of the