Mobile antennas for radio communication are designed to make use of a metal plane as part of the radiating functionality. The metal plane is typically the flat portion of a vehicle boot or roof, and it is this plane which helps to radiate the signal outward and evenly. Base antennas make use of metal wires near the bottom for the same function, and these wires form what is termed a "counterpoise." A mobile antenna may be used as a base antenna as long as it is set onto the centre of a flat metal object and elevated.
Dig a 4-feet deep by 1-foot wide hole at the location where the antenna will be installed.
Set one end of the wooden post into the hole and hold it vertical while filling in the hole with soil to stabilise the post. Place the soil in the hole in small portions and use the end of the shovel handle to tamp down each layer for a more solid post installation. Continue until the hole has been filled in and tamped completely.
Place the sheet metal on top of the wooden post and centre it. Drill a 1/4-inch hole through the centre of the sheet metal and continue drilling as far down into the wooden post as the drill bit will allow.
Insert a 1/4-inch screw through the sheet metal and down into the sheet metal. Use a screwdriver to drive the screw fully into the wooden post. When complete, the screw head will adequately secure the sheet metal plane to the top of the wooden post.
Set the mobile antenna on top of the sheet metal and situate the antenna base so it is mounted in the absolute centre of the sheet metal. If the screw head is in the way, offset the antenna off to one side of the screw head, but as close to the screw head as possible.
Run the coaxial cable from the antenna to the location where the radio is installed and connect.
An alternative to installing a post with a piece of sheet metal on top is to visit a local junk yard and ask for an old inoperable refrigerator. Mobile antennas used as base antennas, should be a minimum of 6 feet above ground for best transmission and reception --- the higher the better. An old refrigerator can be located where desired, and the mobile antenna set on top of the unit, centred, which will satisfy the mobile antennas need for a ground plane and the minimum height. Ask a local radio store to assist you with installing a "standoff" on your radio tower on which to set the mobile antenna if you desire to place the antenna near the top of a radio or TV tower. This will require some climbing and welding, which should be performed by a professional.