The OMNI-A0099 omni-directional antenna is designed for monitoring of horizontally polarised RF signals in the frequency range 20 to 500 MHz.
The band is covered by 2 antennas: a crossed-dipole fed in quadrature for the low frequencies, and a four-feed loop antenna for the upper band. The loop radiation pattern has a null at top and bottom, eliminating structure interactions that plague crossed-dipoles mounted with other antennas.
A generous central cavity allows several large cables to be passed through the antenna, for feeding other bands or DF antennas higher up the stack. The substantial mast and flanges allow heavy antennas to be mounted above the omni.