CHA TD
Page 9
CHA TD configurations provide some capability in each distance category, so depending upon the complexity of
your communications network, you may need to select the best overall configuration. The directionality column
indicates the directionality characteristic of the antenna configuration. When using NVIS, all the configurations are
omnidirectional. “Hasty” and “Deliberate” in the deployment column indicate the relative complexity of site
selection and setup for each antenna configuration.
(Note: * see configuration for coverage)
Sloping “V”
The CHA TD Sloping “V” configuration, see figure (1), is a broadband medium to long range HF antenna. This
configuration exhibits directionality towards the opening of the “V” at medium to higher frequencies, while on
lower frequencies it is bidirectional to the sides of the “V”. It requires only a single support and can be mounted at
heights from 3 to 40 feet, with around 25 feet providing good overall results. An opening angle of 90° will provide
good overall performance, but angles from 180° to 60° can be used to fit the antenna to the site or to improve
performance. Larger opening angles increase performance on lower frequencies and smaller angles on higher
frequencies. At 180°, the antenna becomes an Inverted “V” antenna. The antenna may also be mounted
horizontally using three 10 foot tall supports.
Figure 1. Sloping V Antenna Configuration.
Site Selection and Preparation.
1.
Select a site to deploy the CHA TD Sloping V
configuration, see figure (1). The best site
should have a tree or other support that would
enable the Matching Transformer to be at a
height of around 25 to 40 feet. If a tall 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.
2.
Remove the Matching Transformer (a), Paracord
(h), Antenna Wires (b), Coaxial Cable (j), and two
Stakes (i) from the Backpack (s).
3.
If not already attached, connect a Carabiner to
each end of both Antenna Wires.
Connect the Matching Transformer. Refer to figure
(2) for steps (4)
–
(9).
4.
Connect a Carabiner (e) from one Antenna Wire
(b) to the Transformer Eyebolt (n).