Allows focus on off-axis EIRP, rather than signal shape, to open door to smaller, cheaper dishes
The FCC has adopted new rules making it easier to obtain routine and rapid processing of applications for small C-band and Ku-band transmit-receive earth stations. One purpose of the rule change is to facilitate and expedite approval of small earth station antennas that could be used to extend broadband services to rural areas.
Under the prior rules, the FCC routinely approved C-band antennas with a diameter of 4.5 meters or greater diameter and Ku-band antennas of 1.2 meters or more, as they are large enough to shape the beam to avoid spillover signals that could interfere with adjacent satellites. Smaller antennas could be approved, but only after case-by-case scrutiny to make sure that the antenna had no more potential for interference to adjacent satellites spaced two degrees apart than the FCC’s Rules permit.
The new rules allow applicants to demonstrate compliance with limits for equivalent isotropically radiated power (EIRP) at various angles off-axis from the center beam of the signal from the antenna. By looking at off-axis EIRP rather than the shape of the signal pattern, the FCC is essentially giving users the option of using less expensive antennas and simply turning down the power in the main beam to avoid interference to adjacent satellites. The International Bureau will revise FCC Form 312 to provide for specifying compliance with off-axis power limits.
Applicants who wish still to use the old rules may do so, specifying antennas of at least 4.5 meters at C-band or 1.2 meters at Ku-band and certifying that the antennas comply with the two-degree satellite separation rules. Applicants may also specify small antennas with custom showings and opt to wait for individual application review and forego the benefit of expedited routine processing.
When the new rules become effective, the FCC will also implement rules adopted in 2005 but stayed until now, which evaluate patterns and protect antennas from interference starting at 1.5 degrees off-axis in the C-band and 3.0 degrees off-axis in the Ku-band.
The FCC declined to adopt special coordination procedures for elliptical C-band antennas or to revise the current minimum required elevation angle above the horizon to facilitate locating earth stations at extreme northern latitudes. It also did not impose a specific requirement for controlling pointing errors, although it will recognize the usefulness of computerized systems for maintaining pointing accuracy when evaluating non-routine applications.
Finally, for applications for non-compliant antennas, which require a letter of acceptance from the operators of all satellites with which the earth stations will communicate, the FCC declined to add a requirement to obtain certification from operators of adjacent satellites, in light of the fact that adjacent satellite operators normally coordinate between themselves sufficiently to avoid unexpected interference issues.
Finally, the FCC will permit the use of contention protocols to allow multiple antennas in a Very Small Aperture Terminal (VSAT) system to operate with aggregate power above the FCC’s limit. Contention protocols allow multiple antennas to co-exist using the same frequency on the same satellite with very low probability of causing interference. VSAT operators must certify that their contention protocols are “reasonable,” but the FCC declined to adopt any precise definition of that term.
Who knows what will be next? Maybe you will be able to carry a briefcase antenna, open it anywhere, and surf the web in the middle of the desert or atop a mountain.
