The 21-20-02 is a vertically polarized, omni-directional antenna, compatible with radios operating within the 74 to 88 MHZ frequency range. This antenna can handle up to 50 Watts of power and requires no external tuning.

The antenna is constructed using materials and processes that allow operation from –54 to +100ºC and the design comprises an internal contoured element feeding an external top loading bar to optimize gain over the designated frequency band. The entire antenna assembly is filled with closed cell foam to prevent long term moisture ingress and provide high reliability in World wide conditions of service.