SPECIFICS ON FM BROADCAST INTERFERENCE

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• SPECIFICS ON FM BROADCAST INTERFERENCE
• presentation by
• Steve Mitchell, UK

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A LITTLE BIT OF HISTORY

• Changes to ITU Radio Regulations
• recognition of potential interference to
  aeronautical systems
• studies within the ITU
• initial studies
• further enhanced studies
• final ITU recommendations

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GENERAL TYPES OF INTERFERENCE

• Four types of interference to consider
• Type A
• A1
• A2
• Type B
• B1
• 2 signal
• 3signal
• B2

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DIFFICULTIES WITH ILS/VOR/COM

• Extensive testing
• ILS/VOR receivers
• 3rd order intermodulation
• saturation
• Com receivers
• ICAO Annex 10 SARPs requirements
• 3rd order 2 signal
• Desensitisation

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DIFFICULTIES WITH GBASAND VDL 4

• Testing of GBAS and VDL 4 receivers
• same mechanisms apply as for ILS/VOR/COM
• avionics manufacturers tests above 112 MHz
• split in desensitisation requirements
• similar A1and B1 criteria as ILS/VOR
• ICAO Annex 10 SARPs requirements
• 3rd order 2 signal
• Desensitisation

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Co-ordination

• Why co-ordination?
• Between FM broadcasters
• mutual sharing
• Between FM broadcasters and aeronautical
• avoid interference to aeronautical services
• Between aeronautical and FM broadcasters
• avoid potential problems

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Example of co-ordination process

• Example of an approach to co-ordination
• European example
• inside a State
• databases
• computer tools
• agreement mechanism
• between States
• LEGBAC/EBU

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TYPE A1 CALCULATION
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TYPE A2 CALCULATION
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TYPE B1 CALCULATION2 SIGNAL
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TYPE B1 CALCULATION3 SIGNAL
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TYPE B2 CALCULATION
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TRIGGER AND CUT-OFF CALCULATIONS
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ILS PROTECTION
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VOR PROTECTION
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PRACTICAL SOLUTIONS

• WITH AUDIENCE PARTICIPATION