The CD 4030 series rotatable log-Periodic antenna systems offer a performance capability previously unavailable. The unique characteristics of these system provide reliable
communications over short, medium and long-range paths. Design innovation incorporates broad frequency coverage of 4 to 30MHz together with a mechanically stable
structure. Two models of rotatable log-periodic antenna systems covering the frequency range of 4 to 30MHz are available. Engineered and developed by CD, these are
the first antennas of their type to offer the operation and performance capability over the entire 4to 30MHz range.
The model CLP4030B is a high gain ruggedly constructed log-periodic antenna. The CLP4030 series is a reduced-element length version of the CLP6030B. Needing
neither matching circuits nor ground screen, these antenna can be easily erected wherever there is space enough for the tower. The performance specifications and
operational characteristics have been authenticated by actual field tests. The systems are complete with antenna array, support structure, all the necessary guys and guy
anchors, rotator assembly and remote control unit. Each models are equipped with dual support structures. Installation of these systems may be accomplished without
the use of cranes, boom trucks or other heavy equipments.
The CV430-Series are omni-directional HF vertically polarized antenna designed to provide a broadband and
high power radiation capability for fixed transmitting and receiving sites.
These broadband HF monopole antennas are useful throughout the frequency ranges of 1.6 to 30 Megahertz. The antennas have a low angle radiation pattern and provide both short and long range HF communications by ground wave and skywave respectively. The radiation pattern in the azimuth plane is essentially omni-directional while the elevation pattern varies with frequency.
The antennas are formed by two vertical cones, attached together at the base and supported by a vertical tower running through the center of each antenna.
The SWR is nominally 2.5:1. To prevent radiation pattern deterioration at the
higher frequencies, the upper cone is electrically decoupled so that only the lower cone can radiate. At these frequencies, the antenna assumes the characteristics of an inverted discone.
The two cones are formed by a wire cage fabricated of alumoweld wires. The upper cone consists of 6 wires while the lower cone uses 18 wires to improve the impedance characteristics. The monopole is guyed at 6 places around the periphery of the antenna at the junction of the cones. The upper radiating elements also serve as guys for the upper
portion of the structure. 36 radials form the ground screen. Installation of this antenna requires approximately 45 man-hours excluding time required for pouring and curing of concrete foundations and ground screen installation.
A highly corrosion-resisted alumoweld wire is used for the radiator and guy wire of this CV430. Tower is hot-dipped galvanized steel. As a optional, a aluminum tower (A6061-T6) is available.
The CM230 series are omni-directional HF vertically polarized antenna designed to provide a broadband and high power radiation capability for fixed transmitting and receiving sites. These broadband HF inverted cone antennas are useful throughout the frequency ranges of 1.6 to 30 Megahertz.
The antennas have a low angle radiation pattern and provide both short and long range HF communications by ground wave and sky wave, respectively. The radiation pattern in the azimuth plane is essentially omni-directional, while the elevation pattern varies with frequency. These antenna systems are characterized by low VSWR through their respective
band width of less than 2.0:1 nominal relative to 50 ohms unbalanced line.
For each model, a shaped radiator curtain forms a cage around the hot dip galvanized steel vertical support tower. Since the upper portion of the radiator curtain is connected directly to the tower, the main upper elements also serve as guys fbr the upper portion of the structure. The vertical radiators are terminated into the feed terminal assembly at the base of the antenna and insulated above ground by ceramic suspension insulators, with the mast. RF feed is accomplished through connection between the feed terminal assembly. Maximum utilization of electro-mechanical component proved an extremely reliable system, both electrically and mechanically. The use of cranes are not required fbr erection of CD inverted cone antenna systems.
The antennas operate over a ground screen of 36 and grounded at the perimeters by a series of copper clad ground rods.
Installation of any of the models requires approximately 50 man-hours excluding time required fbr pouring and curing of concrete foundations and ground screen installation.
The 320D log-periodic antenna is designed specifically to support reliable short-medium range communications. Vertically polarized antennas can not always provide reliable short range coverage because of limitations in the radiation pattern or excessive attenuation of the ground wave.
In support of this short-medium range communication, the 320D is designed to direct energy straight overhead, and in addition, 320D has an omni-directional azimuth plane pattern, provides optimum coverage fbr communication centers, such as an air-ports, fbr ground-air and shore stations fbr shore-ship communications etc.
The 320D is extremely efficient, and no loss terminations are used. No ground losses are occurred, thus 320D will outperform the traditional conical monopole or inverted cone antenna. The broad band characteristics and low VSWR exhibit over the entire operating range make the model 320D an ideal replacement in situations where several antennas
have been previously required.
Structurally, the antenna is supported by a single galvanized steel tower, it consequently contributes to decrease the installation and maintenance costs, and the required land area too.
The CD short-medium range CL247 series antenna system
has been designed to provide, unsurpassed short to
medium range performance through their respective
frequency ranges. Due to the characteristics in
log-periodic designes, these system provide radiation
efficiency which is maintained at a high level. This high
radiation efficiency assures that maximum input power is
radiated rather than partially dissipated. These systems
exhibit VSWR characteristics below 2.0:1 across the
designed frequency spectrum with the VSWR remaining
below 1.6:1 over 80 percent of the specified bandwidth.
The radiation pattern of these antennas exhibits a
front-to-back ratio exceeding -10 dB with front-side ratio
exceeding 20dB relative to the principle lobe intensity.
These characteristics assure a minimum of off-path
interference. Radiation pattern characteristics are shown
in the specification summary and have been examined
through calculations to provide maximum front gain at
take-off angles optimum to specified or required path
distance. Ground screens are not a part of these system
nor are they required, due to insignificant effects upon
performance over average or poor earth.
Frequency Range: 500 KHz to 30 MHz
Power Handling: 5000 W Average
High reliability
Easy erection
Excellent electrical stability
Low cost installation
Low cost maintenance
Available with side feed or feed through input
