Antenna Principles
Antennas are constructed of conductive material, typically wire or rigid metal. The antenna element is tuned by length to resonate with the designed frequency. The antenna element is mounted with insulators to a frame. Progressively larger or smaller quads are then spaced and placed on either side of the driven element to generate a directional propagation pattern. These are called directors if they are ahead of the driven element, or reflectors if they are behind the driven element.
Construction Technique
Antennas for receiving or transmitting require electrical or radio frequency insulation. This insulation keeps radio frequency energy on the driven elements and on the lead-in wires where it belongs. A conductive antenna frame may distort your radiation pattern and may harm your transmitter. Transmitter harm is possible when transmitting into an out-of tune antenna load
Quad Construction Technique
If wire is used, fiberglass, bamboo or PVC may be used to retain the shape of the quad. Typically, the main horizontal mast is fastened to horizontal and vertical frameworks which support the quad elements. Drilled holes in the frame may be enough to mount the wire antenna elements.