Review of DTV helix installation on unmanned airship

A number of telecommunications experiments were flown on an autonomous, 68 metre non-rigid airship in November 2004 [1]. Although the digital television broadcast experiment was successful, it was found that the signal was occasionally entirely lost when the airship passed directly over one receiving station. Initially, a quarter wavelength monopole on a simple model of the airship gondola was studied using a commercially available MOM software in attempt to identify features of the gondola that may have adversely affected the radiation pattern of the real broadcast antenna. The study was then extended to a more realistic conical beam, circularly polarised, quadfilar helix. The ground handling bars were found to affect the radiation patterns of both antennas.