CHA HYBRID - MINI / MICRO
Page 12
hastily deployed. This configuration is predominately omnidirectional, becoming slightly unidirectional towards
the end of the antenna wire as the frequency increases. The Sloping Wire requires one support and should be
mounted at a height of 25 to 40 feet for best performance. A counterpoise wire, with a length of 20 to 40 feet, is
recommended. If a counterpoise is not used, the coaxial cable must be 25 to 100 feet in length, as the shield of
the coaxial cable provides the counterpoise. Use the following procedure to install the Sloping Wire configuration.
Site Selection and Preparation.
1.
Select a site to deploy the CHA MPAS Sloping
Wire configuration. The site must have a
support that will position the end of the
Antenna Wire at a height of 25 to 40 feet. If the
right support is unavailable, any convenient
object, such as a fence post or the top of a
vehicle, may be used as a field expedient
support with reduced performance.
Refer to plates (2) and (3) for steps (3) – (8).
2.
If not already attached, connect a Carabiner (d)
to the Isolation Loop (c) at the Wire Connector
(f) end of the Antenna Wire.
Connect the Hybrid Micro Base.
3.
Temporarily remove the Antenna Shackle (j)
from the Antenna Connection (h).
4.
Place the Wire Connector from the Antenna
Wire over the Antenna Connection and replace
the Antenna Shackle. Tighten the nut snugly.
5.
Connect the Carabiner from the Antenna Wire
to the Antenna Shackle.
6.
If using a counterpoise wire, connect it to the
Counterpoise Connection (i). Tighten the nut
(not supplied)
snugly.
7.
Connect a CHA RFI CHOKE and coaxial cable or
the Integrated RF Choke end of the CHA Coaxial
Cable assembly to the UHF Socket (g) on the
Hybrid Micro Base.
Raise the Antenna.
8.
Using a Bowline, or similar knot, tie a long
length (50 feet or more) of Paracord to or
Isolation Loop at the end of the Antenna Wire.
9.
Using a throw weight or some other method,
loop the Paracord over the support.
10.
Raise the end of the Antenna Wire to the
desired height and secure it to the support using
a Round Turn and two Half Hitches, or similar
knot.
11.
Using a Bowline or similar knot, tie the end of a
short length (around 4 feet) of Paracord to
Carabiner.
12.
Fully extend the Antenna Wire so that it is not
quite taut.
13.
Drive a stake into the ground around two feet
beyond the end of the Antenna Wire and tie the
Paracord from the Hybrid Micro Base to the
stake using two Half Hitches, or similar knot.
Extend the Counterpoise.
14.
If using a counterpoise wire, extend it along the
ground in any convenient direction.
15.
Perform operational test.
Inverted “V”
The CHA MPAS Inverted “V” configuration, see figure (5), is a broadband short to long range HF antenna. This
configuration will provide good NVIS and medium range sky wave propagation on all frequencies and long range
sky wave propagation above 14 MHz. It is omnidirectional below 11 MHz and bidirectional towards the ends of the
antenna above 11 MHz. This is a good configuration for EMCOMM when communication is needed both inside and
outside an affected region and the region is too large or mountainous for effective VHF coverage. The Inverted “V”
requires one support in the center of the antenna wire and should be mounted at a height of around 30 feet for
best performance. A 60 foot long counterpoise, which is not supplied, is required. Use the following procedure to
install the Inverted “V” configuration.
Содержание CHA MPAS
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