Comments on: Google’s space odyssey…

By: Could Google offer a sky bridge to new inflight connectivity options? | Runway GirlRunway Girl

Thu, 19 Jun 2014 08:17:43 +0000

[...] platform by the end of the decade. Still, given the circumstantial evidence available today (see here, here, here and here) it is worth looking more closely at what impact this move might have on the [...]

By: Google begins its satellite push, buying Skybox for $500M — Tech News and Analysis

Tue, 10 Jun 2014 22:34:41 +0000

[...] The details of Google�s satellite plans are slowly starting emerge, and we don�t know how all of these pieces will fit together. But if you want to get an idea of what a Google space-based network might look like, check out satellite communications analyst Tim Farrar�s detailed blog post on the subject. [...]

By: satman

satman — Mon, 02 Jun 2014 19:15:50 +0000

No doubt there are coordination and frequency clearance issues that have to be resolved. Google can install gateway stations at their big data centers which are located near the hydro electric power plants in the Pacific NW and have fiber pipes. dane1234 said “12.75�13.25 GHz. Those frequencies are also used by 12.70�13.25 GHz TV Broadcast Auxiliary Service (BAS) stations. Any newcomer feeder uplinks would have to demonstrate protection of incumbent 13 GHz TV BAS stations.” That should not be an issue if the gateways are in Oregon or Central Washington State and the earth stations are shielded by earth or faraday shielding.

I remember the excitement and hype when Teledesic was first announced and I knew some of the people that were on the development team. With Google involved, a 5 billion $$ satellite constellation is doable now that there’s a confluence of technologies ( small sat platforms, flat electronic tracking VSAT’s, cheap LNB’s and BUC’s)) plus some very smart people from the satcom industry developing it.

By: dane1234

dane1234 — Sat, 31 May 2014 22:38:19 +0000

If Google plans to benefit from the ET Docket 98-106 rulemaking (Skybridge) by deploying 11.7-12.2 GHz Ku band satellites, it will presumably mean an increased number of NGSO FSS gateway (feeder) uplinks at 12.75�13.25 GHz. Those frequencies are also used by 12.70�13.25 GHz TV Broadcast Auxiliary Service (BAS) stations. Any newcomer feeder uplinks would have to demonstrate protection of incumbent 13 GHz TV BAS stations. Further, per non-government footnote NG-53 to the Section 2.106 Table of Frequency Allotments, no feeder uplinks are allowed in the 13.15�13.25 GHz sub-portion of the band within 50 km of the top-100 TV markets. And, since the 98-106 rulemaking and the successor ET Docket 03-254 rulemaking, Part 101 Fixed Service (FS) stations can now share the 13 GHz TV BAS band if they are outside the operational areas of all 13 GHz TV Pickup stations. So that means any newcomer gateway uplinks will have to demonstrate protection of both Part 74 TV BAS, and Part 101 FS, links.

An uplink communicating with a geostationary satellite can often be successfully frequency coordinated with terrestrial links, since the uplink antenna’s azimuth and elevation angle are fixed. But an uplink communicating with a non-geostationary satellite has to track the satellite across the sky. Over time, the main beam of the uplink antenna will sweep out virtually all azimuths and elevation angles. Therefore, an NGSO uplink is much more difficult to frequency coordinate with existing co-channel terrestrial uses. Hopefully Google will select remote uplink sites, or sites with sufficient terrain obstruction to ensure no interference to incumbent terrestrial operations, while still providing reasonable look angles to a new constellation of NGSO satellites.