The HT-21 is a transportable HF antenna designed for rapid deployment in any one of three configurations for support of communications paths up to 1,000 miles. Configuration A is for short range skywave propagation on path lengths up to 300 miles. Configuration B is used on paths ranging from 200 to 500 miles. Configuration C is used for 400 to 1,000 miles paths. These multiple configurations and the ease of erection make the HT-21 ideally suited for changing operational environments.
The HT-21 features a telescoping pneumatic mast designed to meet the ease of handling and quick erection requirements of a transportable system. The mast can be extended utilizing either an air compressor or a foot operated air pump. The antenna is supplied with mast, guys, balun, terminations, anchors and two transit cases. It offers high efficiency and excellent gain characteristics in each of the three configurations.
The HT-21 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 is available in input power levels, the /1 version operates up to 1 kW avg / 2 kW PEP, the /2 version operates up to 10 kW / 20 kW PEP 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, guys, antenna, balun, terminations, anchors and transit cases.