SELECTING THE RIGHT AERIAL:

• Gain describes the shape of the radiation from an aerial. Use a higher gain antenna for better performance in open flat terrain. Use a lower gain antenna for better performance in rough mountainous terrain.
• It is recommended that you use a lower gain antenna for the communication between multiple vehicles in a convoy situation.
• When operating between mountainous and open terrain,think about choosing an aerial with an interchangeable high gain and low gain whip tops or use two seperate aerials witha switch.
• Stainless Steel whip aerials will NOT last on corrugated roads, they are NOT suitable for this application.
• For better performance locate the aerial higher on the vehicle.
• Ground Plane Independent (GPI) aerials can be mounted anywhere on the vehicle. They provide consistent performance all the way aroung the aerial. These aerials work independently of the vehicle body.
• Grounded aerials rely on the metal surface of the vehicle for performance. If you mount this style of aerial on the edge of a vechicle, the radiation pattern will be biased towards the area with the largest amount of metal, (an offset pattern). There will also be a deteriotation in the VSWR of grounded aerials, mounted on the edge of the vehicle. Grounded aerials generally should only be mounted in the centre of the vehicle roof.

MOUNTING MOBILE AERIALS:

• DO NOT mount aerials close to each other. Minimum distances should be 70cm between aerials. The further apart the two aerials, the beter the performance of each respective aerial.
• DO NOT mount aerials closer than 70cm to any metal vertical surface.
• DO NOT mount aerials operating on the same band, at the same horizontal level unless a switch selects them.