The AX-61S antenna is a rugged, broadband quarter-wave ground plane omni-directional antenna suitable for military and commercial marine use, in particular in sonobuoy applications.

The AX-61S antenna is constructed from marine grade aluminium and will withstand harsh marine environments and wind speeds up to 150 mph (250 km/h). The high durability epoxy based coating is resistant to chemical corrosion, abrasion, ozone and ultra violet radiation. Furthermore, the coating also significantly reduces precipitation static.

The antenna is designed for simple and fast installation. The ground plane radials are bonded to the support tube and the coaxial braid. Provided the antenna is clamped with a good electrical connection to a grounded mast/support, the radials will be at DC ground to further reduce the effects of static build up.

RF connection is by way of an "N" connector (female) under the base of the active element support.

The antenna covers the frequency range 135 to 175 MHz (alternative frequency ranges are available upon request).