The HT-21B is designed to meet the specific requirements of the AN/TSC-122 communications shelter requirement for sloping -v antennas. It is a transportable antenna designed for rapid deployment in either of three configurations designed for support of short, medium or long range HF skywave circuits. Configuration A is for short range skywave propagation on path lengths up to 700 KM. Configuration B is used on paths ranging from 700 to 1500 KM. Configuration C is used for 1500 to 4000 KM paths. These multiple configurations and the ease of erection make the HT-21B ideally suited for changing operational environments.
The HT-21B features a telescoping fiberglass/carbon composite mast designed to meet the ease of handling and quick erection requirements of a transportable system. The HT-21B is a terminated Vee type dipole that is supported between a 40 foot telescoping mast and two 15 feet poles which also contains the termination resistive loads. The balun is located at the top of the mast. The stowed configuration of the antenna is less than 6 feet in length, weighs less than 170 pounds and stows in a small volume. The antenna is supplied with mast, guys, balun, terminations, and anchors. It offers high efficiency and excellent gain characteristics in each of the three configurations.
The HT-21B provides flexible operation for short to long range circuits in the 2 to 30 Mhz band. A mast-top mounted balun provides a nominal input impedance of 50 ohms. The input VSWR is less than 2.0:1 across the 2 to 30 Mhz band for all three configurations. The antenna operates with up to 1 kW avg / 2 kW PEP RF power using an air cooled balun. Erection time for all three configuration is less than 60 minutes with two men, the time required to change from any configuration to any other is less than 30 minutes.
Mast, end poles, guys, antenna, balun, terminations, anchors and transit bags.