Before the launch of HS4 Mobile, a quest for the search of a default antenna which could be bundled with this application began. Unlike the regular HS4 desktop platform which is akin to a base station, the requirements were far more stringent for this default antenna. Apart from being an all HF band antenna with Omni-directional capabilities it had to be light-weight and field deployable. We decided to go for a high efficiency and yet a portable design. We chose to go with the vertical 1/4 wavelength design, but to make it multi-band, easily deployable and structurally stable we opted to use an Open Sleeve vertical (OSV) configuration. The radiating elements are copper wires push through collapsible length of Fiber-glass rods.
By design, the OSV antenna uses a separate copper wire element for each band. These elements are run parallel along the main fiber-glass section in close physical proximity to enable all these elements to be driven by electro-magnetic induction from the main element within the fiber-glass rod. As a counterpoise, the OSV employs 16 optimal length horizontal radials made of copper wires too.
As a default HS4 Mobile system antenna, the OSV features a clean, Omni-directional, radiation performance and is good for working medium range and long distance (DX) on all bands from 160m-10m. The 80m and 160m element is the core central element that runs through the central fiber-glass sleeve. The 160/80m band segregation is achieved using a trap which also allows the overall length of the antenna to be shortened considerably. The radiating elements for all other bands are surrounded in close proximity to the central element.