Model SD9-128 118-137 MHz 9 dBd Gain 


Design Features: The SD9-128 ultra high performance VHF aviation band stacked dipole array is designed for use with highly populated radio sites requiring long haul omni-directional coverage. The SD9-128 is heavy duty stacked dipole array features, wide bandwidth, high gain, high power handling capacity, low VSWR, low noise performance and null filling coverage with omni-directional characteristics. This stacked dipole array maintains constant gain and VSWR over its 20 MHz bandwidth, making it highly suitable as base station antennas for repeater, paging and any other multi-channel communication systems. The radiation pattern can be changed in the field by use of common hand tools. The Vertical stacking distance is factory adjusted for highest possible efficiency. Specially designed center fed phasing harness ensures equal and in phase signal distribution to all the eight dipoles. The SD9-128 High gain stacked dipole array operates at D.C. ground for protection against lightning.

Constructions: The stacked dipole array uses 6063T6 ultra corrosion resistant architectural anodized aluminum, consists of Eight folded dipoles stacked vertically, fed in phase. The center fed dipole ends and cable connections to the dipoles are sealed in epoxy at the end of the boom for protection against weather and imparting rigidity and strength to the dipoles structure. All the fasteners are made of marine grade SS. The 12 Meters long central mast for mounting the dipoles is shipped in four sections of 3 Meters each for easy of shipping. The dipoles are mounted on a tubular boom made of high strength aluminum alloy, which offers a low resistance discharge path against any lightning strike during the stormy weather. The N-Female termination of antenna sealed in flame retardant heat shrinking tube ensures complete waterproofing. The antenna can be supplied with or without central mast.

Electrical Specifications:
Frequency Range118-137 MHz
Gain9 dBd
Bandwidth20 MHz
Antenna TypeDipoles
Input Impedance50 Ohms
Horizontal Beamwidth -Half Power Points360 Degrees in Omni Configuration
180 Degrees in Offset Configuration
RF Power Handling Capacity500 Watts
Input TerminationN-Female
Lightning ProtectionDirect Ground

Mechanical Specifications:
Materials6063T6 Aluminum Alloy
Mounting Hardware -MaterialsMarine Grdae Stainess Steel
Wind Rating180 Km/Hr.
Overall Length12 Meters
Dipoles Aluminum - O.D.12.7 mm
Shipping Length3 Meters
Support Pipe O.D.51 mm (2 Inches)
Support Pipe Material6063T6 ALuminum Alloy
Maximum Mount Pipe Diameter 52 mm (2 Inches)
Gross Weight45 Kg. with central mast

Environmental Specifications:
Operating Temperature(-)30 to +70 Degrees Celsius
Storage Temperature(-)40 to +80 Degrees Celsius
Humidity0 to 95% RH