VMES Okay, Commenters Say, Disagreeing on Limits

VMES rules could be based generally on rules covering shipboard earth stations, most said, but many want tougher provisions. Airline communications body Arinc said that even using automated pointing devices “terrain has the potential to cause more severe pointing errors” for the antenna. And VMES likely will use smaller antennas, which can boost interference to others and be more vulnerable to interference. That, it said, “would require other Ku-band operators to adjust their own operations” to avoid interference.

Downplaying interference issues, General Dynamics said it has run VMES systems under experimental or special temporary authority four years without complaint. It noted FCC concerns that allowing VMES could mean more widespread deployment by less-expert operators, but predicted that the high cost of VMES would limit its presence to “perhaps only slightly more” units than the existing number of shipboard units.

Boeing endorsed easy access to VMES, but said the same should apply to airplane-mounted earth stations. “Many currently available technologies, including active radio frequency tracking and predictive tracking antennas, electronic phased array antennas and spread spectrum modulations, are not dependent upon the type of vehicle on which they are mounted,” Boeing said. Several FCC proposals for limiting interference are unnecessary, including the so- called 10*log(N) rule, a three-degree starting angle, and pointing accuracy rules, it said.

Properly handled, VMES can “operate transparently” with existing Ku-band services and expand broadband availability, the Satellite Industry Association said. But it backed most of the interference-limiting rules proposed in the FCC rulemaking.

Public broadcasters have “serious concerns” about VMES, since the Public Broadcasting Service uses the bands to send programming to member stations and receive content from them, they said. They fear that rough terrain, sharp turns and even “hitting obstructions” will keep the small antennas from maintaining adequate pointing accuracy, commenters said. “The expanded use is even more troublesome because in many cases the source of interference will not be identifiable” due to techniques like spectrum spreading. “Exhaustive” testing of each equipment type, use of automatic transmitter identification and hub master station monitoring are needed to minimize these negatives, they said.

The National Academy of Sciences raised concerns about the effect of VMES on radio astronomy and similar services, particularly at 14.47-14.5 GHz.

The Fixed Wireless Communications Coalition (FWCC) called the 11 GHz band critical to member companies wanting to use the spectrum to provide wireless backhaul to carriers. FWCC doesn’t object to VMES downlinks at 10.95-11.2 GHz and 11.45-11.7 GHz, provided satellite operators can live with some interference, it said. The FCC is considering an order to allow smaller antennas for 11-GHz transmissions. This will mean more use of the band for backhaul, the group said.

“The 10.7-11.7 GHz band is important to the fixed service,” the group said. “With the 2 GHz band having been reallocated to other services, the near-total blockage of 4 GHz by C-band earth stations… and increasing difficulties in coordinating 6 GHz links in congested areas -- again, due in large part to earth station proliferation -- 11 GHz is often the lowest frequency available for new links,” FWCC said. “For reasons of range, antenna size, capacity, availability, and other factors, 11 GHz is the last remaining ’sweet spot’ for many backhaul applications.”