VAS 3-Turn Helical 7.5dBi

Video Aerial Systems (VAS) is an American company focused on the development and manufacture of antennas. It owns several patents, and its antennas rank among the very best.

VAS 3-Turn Helical 7.5dBi is a directional antenna with right-hand circular polarization RHCP, an SMA connector and 7.5dBi gain for the 5.6-5.96GHz band. It is suitable for the receiving side — directly on FPV goggles with a built-in receiver, a standalone video receiver or a ground station. RHCP polarization is suitable for analog video transmission or HDZero. On the drone, it is complemented by an omnidirectional antenna with the same polarization.

A helix (“helical”) is a spiral antenna. Its radiating element consists of a conductor wound into a spiral, and the number of turns determines the gain — the more turns, the higher the gain and the narrower the beam. This model has 3 turns, so it has the lowest gain and widest coverage in the VAS 5.8GHz helix range. The spiral creates circular polarization with a very good axial ratio. The axial ratio indicates how precisely circular the radiated wave is; the better it is, the lower the losses between transmitter and receiver and the better the antenna suppresses reflections from terrain and obstacles (“multipath”).

The radiation beam is 120°, which is wide coverage for a directional antenna and an advantage of its lower gain. The antenna is tolerant of model movement and head movement and does not require precise aiming, making it suitable for mounting directly on FPV goggles. Several side lobes also pick up signal outside the main beam. The ideal combination on a diversity receiver is with an omnidirectional antenna: the directional antenna provides range and signal penetration through trees and buildings, while the omnidirectional antenna covers the immediate surroundings, takeoffs and landings.

The antenna has no separate mount; it is supported by its own coaxial cable. The cable is rigid and holds its shape — it can be bent 90° in either direction, easily supports the antenna and allows it to be aimed differently from the receiver. It connects directly to the receiver's SMA connector on the goggles, either straight or via a 90° SMA adapter.