1. 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 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 1

2. 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) 2

3. 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) 3

4. 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. 11 th 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 4

5. 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. 5

6. 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. 6

7. 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. 7

8. 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. 8