| AS-1729/VRC |
|
| Physical
Dimensions |
|
| Height |
120
inches |
| Diameter |
5
- 1/2 inches (base) |
| Weight |
9
lbs |
| Operating
Temperature |
-32
C to +150 C |
|
|
| Frequency
Range |
30
to 76 MHz |
| Input
Impedance |
50
ohms (nominal) |
| VSWR |
>
3:1 over freq range |
| Polarization |
Vertical |
| RF
Power Rating |
70
watts |
| Power
Requirement |
Switching
voltage for base tuned circuit selection (22-30 Vdc)
supplied from transceiver |
| Feed
Type |
Unbalanced,
coaxial cable |
| Input
Connector |
Type
C, modified UG-631/U |
|
|
Description:
The AS-1729/VRC is a center fed, remote step-tuned antenna
for use with AN/VRC-46 transceivers on small craft and
vehicles. It is also used on large ships equipped with
AN/VRC-46 for amphibious operations. The antenna consists of
two fiberglass covered whip sections (AT-1095/VRC and
AS-1730/VRC), a base spring assembly, and a base switching
assembly (MX-6707/VRC). The base switching assembly contains
ten LC tuned circuits to match the transmission line to the
antenna over the operating range of the AN/VRC-46. Selection
of the individual tuned circuits is automatic from the
channel selector switch on the transceiver. The antenna
tuned circuits may also be selected manually by a switch on
the base of the assembly.
Installation: The base assembly has four bolt
holes for mounting the antenna to its support structure. The
base may be mounted through a metal boat's skin or on an "L"
shaped bracket attached to the ship's superstructure or
mast. If the AS-1729/VRC is installed on other than a deck
mounting, it will be necessary to provide a ground plane.
The ground plane should consist of four horizontal, equally
spaced metal rods 54 inches in length mounted out from the
base of the antenna and electrically connected to the ship.
Considerations: The AS-1729/VRC Antenna was
designed for use on land or amphibious vehicles. The spring
base was provided to furnish the flexibility for vehicular
operation where contact between the antenna and overhead
obstruction could be expected. Since this requirement does
not exist onboard ship and corrosion has been experienced
due to dissimilar metals used in the manufacture of the
spring mount, a rigid adapter piece has been designed for
replacement of the spring section. Details for the
manufacture and installation of this adapter piece are
contained in NAVSHIPS 0967-177-3030 SHIPBOARD ANTENNA
SYSTEMS, ANTENNA COUPLERS, COMMUNICATIONS ANTENNA SYSTEMS,
Section G. |
