| AS-857/GRC |
|
| Physical
Dimensions |
|
| Height |
168
inches |
| Diameter |
9
- 1/4 inches |
| Weight |
50
lbs |
| Operating
Temperature |
Unavailable |
|
|
| Frequency
Range |
225
to 400 MHz |
| Input
Impedance |
50
ohms (nominal) |
| VSWR |
>
1.8:1 |
| Polarization |
Vertical |
| RF
Power Rating |
2
kilowatts (average) |
| Power
Requirement |
None |
| Feed
Type |
Unbalanced,
coaxial cable |
| Input
Connector |
Type
LC |
|
|
Description:
The AS-857/GRC is a high power dipole array which provides
broadband, omnidirectional coverage for general purpose
communications use in the 225-400 MHz frequency band. It has
a minimum gain of 7 1/2 dBi and is intended for use in
ground installations where high RF power levels and moderate
antenna gains are required.
The antenna is a
parallel-fed, colinear array of four radiating elements
enclosed and sealed within an epoxy fiberglass radome for
prolonged use under severe environmental conditions.
The array handles average
input powers to 2 kW. It is untuned and operates over its
entire frequency range with a VSWR, on 50 ohms, of less than
1.8:1. Maximum signal intensity is directed near the
horizon, with a nominal 5° uptilt to minimize the
effects of ground reflections. The half-power beamwidth over
the design band is 10° - 18°. Azimuth coverage is
omnidirectional to within +/- 1 dB.
The upper radiator is
altered to produce a small horizontal current component.
This signal, radiated upward, efficiently fills the overhead
cone of silence.
The RF input connector is
a coaxial Type LC connector. The connector and a radome
purging plug are recessed in the antenna base. |
