Prior to providing a proposal to install an AM detuning system, obtain a set of installation specifications from the detuning device’s manufacturer to ensure that you are aware of all product-specific requirements.
Before the system is fabricated the manufacture will require a set of tower drawings from the client for the dimensions for all skirt and detuning box attachment hardware. The height of the structure will affect your pricing. However, the only additional labor for a taller structure is to provide a few more attachment brackets for the skirt.
An average price that a contractor will charge to install a system on a on a typical structure, monopole or self supporting tower is $1,200 to $1,500 when they are on site. If you are the turnkey contractor for a guyed tower that is being detuned, add the additional labor for the installation of insulators when the guy wire must be broken up into suitable electrical lengths. Sometimes it becomes necessary to use Phillystran or other non-metallic guy wires. Prior to providing a proposal to install an AM detuning system, obtain a set of installation specifications from the detuning device’s manufacturer to ensure that you are aware of all product-specific requirements.
Typical Skirt Designs
The typical detuning skirt is comprised of a minimum of three wires about 3/8” in diameter, although there are occasions where a single wire will be adequate. The three wires are spaced equally about the structure and strung alongside the length of it, between 16 and 30 inches away from the structure. At the skirt’s top, the wires are bonded to the tower. At the bottom of the structure the wires are connected together by a wire hoop around the structure and fed into the capacitive coil box.
A pigtail wire connects the bottom hoop to an electrical tuning circuit housed in a weatherproof box. The other side of the circuit is connected to the structure's electrical ground.
Stand-off insulators are used to ensure that detuning wires do not contact the tower. This is absolutely critical to ensure proper operation of the detuning network. Stand-off insulators on the vertical portion of the tower are used to prevent long lengths of skirt wire from oscillating and striking and shorting out on the structure.
Most detuning systems are manually operated and do not require any electrical connection, but some systems do have motor driven detuning networks.