An island nation has deepened its understanding of reconciling FM broadcasts with aviation navigation systems.

ATDI prepared a report for the spectrum regulator in The Seychelles, the Department of Information Communications Technology (DICT), on compatibility between Band II broadcast and instrument landing system (ILS) localiser, VHF omni-directional radio range (VOR) and VHF communications (COM) equipment operating in the 108 to 137 MHz band.

The report author, ATDI lead engineer Simon Parsons, visited the country and ascertained emissions at a number of FM broadcast sites.

He comments: “We visited the sites involved and made measurements and inspections based on the situation on the ground with a view to reproducibility and later reuse of the techniques by DICT staff. The aim was to enable DICT to maintain an overview of the situation in the future, with staff capable of identifying potential problems and plan spectrum usage with confidence that the decisions they make will not result in harmful interference to air navigation systems in use in The Seychelles.

“As always, the aim is to recognize that spectrum management is a collaborative effort between the regulator and the licensees.”

No evidence of intermodulation or harmonic interference to aeronautical navigation systems was detected across The Seychelles but ATDI recommended additional filtering at some shared FM broadcast sites and that frequencies on each FM site should be calculated to ensure new entrants into the radio market do not have the potential to create interference.

“It is indicative of ATDI’s flexibility and global presence that the company is equally comfortable in a remote archipelago like The Seychelles and in Europe’s most crowded urban environments,” Simon notes.

Paul Pierre, Head of spectrum management at DICT, adds: “As with every spectrum regulator across the world, DICT is determined to used frequency resources in a way that maximizes benefit to the nation while giving spectrum users the services and safety they require. This report helps us to move forward in both areas.”