Selecting an antenna location on a vehicle is critical for ensuring optimal signal performance, range, and clarity. The general rule of thumb is to place the antenna as high as possible and as close to the centre of a large, flat, metallic surface (such as a metal roof) to maximize the ground plane and ensure a 360-degree, omnidirectional radiation pattern. 

Here is a guide to selecting an antenna location based on vehicle type and antenna type:

Most Common Antenna Car Mount Locations

Best Locations for Performance

Centre of the Roof: The ideal, most efficient location for almost all antennas (CB, VHF/UHF, PRS, Commercial, etc). It provides the best, most symmetrical ground plane.
High Point of Pickup Bed: For trucks where a roof mount is impractical, the top of the cab or a high point on the truck bed provides good height.
Centre of the Trunk Lid: A solid alternative to the roof, offering a good, large metallic surface for a ground plane. 

Vehicle-Specific Recommendations

Off-Road/4x4 Vehicles:

• Roof: Best, but requires protecting the antenna from branches.
• Bull Bar: Common for antennas, but generally provides a poor ground plane, making "ground-independent" antennas necessary.
• Rear Spare Wheel Holder: Good for avoiding drilling, using a metal bracket for grounding.

Trucks/Semi-Trucks: Side mirrors are common, but ensure they are properly grounded to the chassis.

Campers/Fiberglass Vehicles: Because these lack a metal surface for a ground plane, use specialized "no-ground plane" antennas or create a "fake" ground plane using copper or aluminum foil (at least 10 cm in diameter) underneath the antenna. 

Common Pitfalls and Technical Factors

• Insufficient Ground Plane: If the antenna is not mounted on a large enough metal surface, the signal will be weak and unbalanced, particularly for VHF/UHF and CB, which rely on the car's body.
• Obstructions: Avoid mounting near large metal objects (e.g., roof racks, light bars) which can cause signal reflection and distortion.
• Cable Routing: Do not pinch, crush, or sharply bend the coax cable. Route it through existing channels or weather stripping to avoid damage.
• Safety Interference: Ensure the antenna does not obstruct cameras, sensors, or interfere with collision-avoidance systems. 

Mounting Types

• Magnetic Mount (Mag Mount): Easiest for temporary, non-invasive installation; best for passenger cars.
• NMO/Hard Mount: Permanent, drilled through the roof or trunk for best, most secure connection.
• L-Bracket/Lip Mount: Ideal for trunk-lip, bonnet-lip, or fender, providing a stable, semi-permanent mount.