DESCRIPTION OF COMPONENTS
GENERAL - This subsection contains a description of the Antenna System and describes the components
therein. The description is referenced to a major component location diagram and to exploded views which clearly
illustrate all of the major components comprising the system. Appendix I, which contains detailed information on the
scope, supplements the information provided in this section.
(1) DESCRIPTION - The Antenna System, which is housed in a 16-foot inflatable radome-platform, is
designed for installation on an 80-foot tower, on a portable hoisting unit or on a portable stand. Two guying structures,
one for the portable stand installation and one for the 80-foot tower installation, are provided. Two lightning rod mounts
and one lightning rod are provided. For system shipment and storage, a transit cover with removable panels is provided.
This cover fits over the disassembled Antenna System and is held in position by snap-lock fasteners.
The Antenna System (Figure 5-2) consists of a 9-foot fiberglass paraboloidal reflector fed by a log-
periodic dipole feed (item 5), an elevation drive assembly with elevation capabilities of from -15 to +95 degrees, an
elevation drive support casting (item 8), an elevation drive support extension (item 7), an antenna pedestal (item 10) with
rotation capabilities of + 300 degrees, two level bubbles (item 24), an elevation data cable assembly (item 2), three rf
cable assemblies (items 67, 68 and 69), and one portable stand.
The antenna has a very narrow beam width and requires both azimuth and elevation rotation
capabilities in order to search for, locate, and receive rf radiation from a point, or points, in space. The antenna operates
over the frequency range of from 1 to 12 MHz. The antenna is also provided with an electromechanical linear actuator
(beam broadener) with a motor-driven mechanism which provides remotely selectable actuation of the linear movement
of the feed support shaft, relative to the focal point of the reflector. The primary effect of defocusing the feed toward the
reflector from the focal point is to increase the phase error across the reflector, broadening the main lobe by several
degrees and reducing the gain of the antenna. The antenna is capable of generating linear polarization only. Each feed
is mounted on a polarization mechanism which rotates it to any one of four orientations to provide horizontal, vertical,
+45-degree or -45-degree linear polarization. Polarization and beam