FCC Issues Vehicle-Mounted Sat Gear Order on Reconsideration

Tuesday the FCC released Order on Reconsideration FCC 13-1 revising its rules for Vehicle-Mounted Earth Stations (VMES) to make them easier to deploy and to provide operational flexibility consistent with other services. The changes are similar to the rules for Earth Stations Aboard Aircraft (ESAA) I reported on last week. The Order addresses petitions for reconsideration filed by The Boeing Company and ViaSat, Inc.

The FCC declined ViaSat's request to clarify the antenna pointing error requirements in Section 25.226(a) of the rules, but did ease the technical requirements for variable power-density VMES systems, including modifying the off-axis effective isotropically radiated power (EIRP)-density provisions in Section 25.226(a)(3) to allow these systems to operate their terminals more efficiently and effectively. The FCC partially adopted a proposal by ViaSat to relax the cessation of emission requirement in Section 25.226(a)(9). This is targeted at lowering the risk of human exposure to RF radiation.

The revised rules grant variable power-density VMES system ALSAT authority (the authorization to communicate with any U.S. licensed satellite or any satellite on the FCC Permitted Space Station List). The FCC denied Boeing and ViaSat's requests to eliminate the 1 dB power-density restriction. The FCC noted this rule was designed to protect the Fixed Satellite Service from harmful interference. Operators can, however, request a waiver of the 1 dB requirement by supplying data that demonstrates that the system has operated without interfering with adjacent satellites while complying with the 1 dB restriction, along with sufficient technical information to allow the FCC to determine if a waiver is warranted.

The Order adds, “a variable power-density VMES operator should file a waiver request after its system has operated at or above 50 percent of its capacity without causing harmful interference.” Applicants seeking a waiver of the 1 dB requirement will retain ALSAT authority.

The major change to the rule affecting protection from RF exposure is designed to accommodate a brief loss of the satellite downlink when the signal is blocked by man-made objects such as overpasses or natural objects such as trees. The revised rule states, “Each VMES terminal shall automatically cease transmitting upon the loss of synchronization or within 5 seconds upon loss of reception of the satellite downlink signal, whichever is the shorter timeframe.”

The Order on Reconsideration emphasized that VMES system operators must still comply with the RF exposure limits in Section 1.310 of the FCC rules to ensure public safety and comply with the professional installation and labeling requirements adopted in the original VMES Order.

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.