Presentation by K' P' Rimal,

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Presentation by K. P. Rimal, Regional Officer of
the ICAO ASIA-PACIFIC Office to the Seminar on
implementation of data link and SATCOM
Communications in the ICAO Regional Office for
the ASIA/PACIFIC Region in Bangkok, Thailand
from 17 19 November 2003 on VHF
Communications current and future use in the
ASIA/PACIFIC Region of ICAO
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VHF Communications Current and future use in
the ASIAPAC Region

• Frequency band 117.975 137 MHz
• Channel spacing as per Annex 10
• 25 kHz
• 50 kHz
• 100 kHz
• 8.33 kHz
• Capacity in VHF band was increased through the
  introduction of SARPs in Annex 10 for
• a. 8.33 kHz channel spacing (1996)
• b. VDL Mode 3 (2001)

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VHF Communications Current and future use in
the ASIAPAC Region

• ASIAPAC Region uses a mixture of
• 100 kHz, 50 kHz and 25 kHz channel spacing
• Voice channels are limited to the frequency band
  117.975 136 MHz
• Frequency band 136 137 MHz reserved for data
  communication (VDL Mode 2, Mode 4)

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VHF Communications Current and future use in
the ASIAPAC Region

• New communication systems are to be implemented
  on the basis of appropriate regional and
  inter-regional coordination in ICAO
• (Re. 11th ANC Rec. 7/5)
• (e.g through a regional Air Navigation
  Agreement)
• This allows for Regional implementation of
  globally available systems, taking into
  consideration specific needs of Regions

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VHF Utilization Plan

• In the ASIA/PAC Region 100 kHz, 50 kHz and
  25 kHz channel spacing was adopted since the
  Asia/PAC/2 RAN Meeting 1983
• The ASIA/PAC/2 RAN Meeting had adopted
  25kHz channel spacing for future assignments to
  meet new requirements.
• Requirements for the foreseeable future
  are expected to be met with 25kHz channel spacing.

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VHF Utilization plan (Contd)

• The ASIA/PAC/3 RAN Meeting held in 1993 in
  its Conclusion 11/4 assigned the ICAO ASIA/PAC
  Regional Office to continue to maintain its
  frequency selection and co-ordination role,
  including the maintenance and promulgation of
  Frequency List No. 3 at periodic intervals.
• Pursuant to the above Conclusion Frequency
  List No. 3 has been published regularly.

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VHF Utilization Plan (Contd)
Conclusion 11/5 of ASIA/PAC/3 RAN Meeting
requires States in ASIA/PAC Region to co-ordinate
frequency assignments for both national and
international requirements.
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VHF Utilization Plan (Contd)
After adoption of a world wide frequency 123.45
for air-to-air communication, frequency 128.950
MHz has been used for TIBA.
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