4 GHz Terrestrial Microwave Discussion

1. 4 GHz Terrestrial Microwave Discussion

2. Topics of Discussion • 4 GHz Committee Comments • Existing Use • Issues

3. 4 GHz Committee Comments • The 3.7 to 4.2 GHz frequency band appears to be underutilized. • 2 GHz users that have had to give up their 2 GHz frequencies 2110-2200 and 1850-1990 could use the 4 GHz band instead of the 6 GHz bands

4. 4 GHz Committee Comments • Would be ideal for narrow bandwidth allocation for 1 DS1 to 8 DS1 low capacity requirements, roughly the same as the 2 GHz bands • 4 GHz band could have frequencies arranged to have both low and high capacity assignments similar to 6 GHz bands

5. 4 GHz Committee Comments • 2130-2150, 2180-2200 Narrow band Local Government , Industrial users could move to 4 GHz.

6. Existing Use • 5000 point to point radios…. not sure if paths or radios. Small number compared to what used to be there. • Receive Only terminals have been severely reduced. Example: Holiday Inn’s no longer use 4 GHz RO terminals. They have moved to LodgeNet and OnDemand worldwide. They are in the 12.2 GHz band.

7. Existing Use • Head end sites for cable TV companies still use 4 GHz RO terminals. • Note: through field verification, Dallas and St. Louis areas TX/RX terminals are mostly dismantled or not operational per actual field research checking against Comsearch’s database.

8. Existing Use • In driving the neighborhoods in North Dallas only one 4 GHz RO antenna was spotted. Not sure if it is operational. • Introduction of the 12.2-12.7 GHz satellite services has probably significantly reduced the use of 4 GHz RO terminals. (No stats to prove this).

9. Existing Use Tim HardyComments • There are about 24 different licensees in the band - most of these are the variations of AT&T - AT&T Communications of California, etc.

10. Existing Use Tim HardyComments • There are about 500 path records in the database, but this does not account for duplicate records.  I would guess that the path count would go down by about ½ once the duplicates (different equipment, etc) are taken out.

11. Existing Use Tim HardyComments • I didn't count the numbers of frequencies but may do this in the future since a number of the AT&T paths only have one channel of orderwire left.

12. Issues • Terrestrial equipment manufacturers do not at the present time manufacturer equipment that operates in the 3.7 to 4.2 GHz frequency band • Other uses are being looked at by other entities, i.e., satellite.An interesting comment heard at the Canadian RABC meeting in Toronto. Telesat emphatically stated that they will be petitioning various regulatory bodies (Industry Canada, WARC) to allocate the 3.7 - 4.2 GHz band exclusively for FSS (Doug Docherty quote)

13. How did the band become a less than favorable frequency band for use by the carriers? Proliferation of RO terminals Lack of interference shielding Numerous AT&T routes making it congested at the time Lack of manufacturers making the equipment Issues

14. Issues • Manufacturers do not want to make 4 GHz equipment because they are afraid of the 4 GHz RO users

15. 4 GHz Terrestrial Microwave Where do we go from here?