What type of antennas are used today for tower-aircraft comms? Are they directional or omni-directional?
As antenas são omnidirecionais, no entanto, na aeronave, a montagem é importante para manter a linha de local e a FAA cobre este AC . Isso se refere a aeronaves de < 12.500LB, mas a lógica se aplica a todos os planos.
d. VHF Com 1 should be mounted on the top of the aircraft since this will provide the best unobstructed location. VHF Com 2 can also be mounted on the top, provided there is at least 1/2 wavelength (of the antenna operating frequency) distance available between antennas.
e. If Com 2 is mounted under the aircraft, a bent whip may be required to provide ground clearance. Bent whips may not provide the best performance because of proximity to the aircraft skin. Signal reflection and obstruction is more of a problem with such locations. Extension of the landing gear or flaps may also impact belly mounted antenna performance.
f. Antennas need to “see” with a direct lineof-site to the source. Antenna patterns can be disrupted by landing gear or vertical stabilizers, for example. When mounting antennas, try to locate them in areas where line-of-sight view is not obstructed.