RF Shorts for Feb. 3, 2014

European Nations Take Steps to Protect Earth Observation Sat Spectrum

Peter B. de Selding's article Europe Mounts Defense of Radar Satellite Spectrum Against Wireless Broadband Incursion on SpaceNews.com argues to protect 5350-5470 MHz spectrum used by the European Sentinel-1 satellites and Canada's next-generation Radarsat Constellation Mission satellites from interference from wireless broadband companies.

de Selding writes:

“In a new version of a similar dispute with satellite telecommunications services operating in a different portion of the C-band spectrum, the terrestrial-broadband promoters--Cisco Systems, Intel, Qualcomm and Broadcom among them—say the frequencies in question can be shared with little or no harm to radar satellites’ effectiveness.

“The study supporting that decision was based on the assumption that 95 percent of the Wi-Fi use would be indoors. However, France, Britain and the 28-nation European Commission did not share that view. The European Space Agency said in a presentation: “SAR measurements would be heavily interfered with if the RLANs are allowed to operate in this frequency band. This would mean severe disruption of the SAR [Synthetic Aperture Radar] measurements over all populated areas: urban, suburban and even rural.”

ESA stated that it had decided to operate Sentinel-1 SAR in this so-called “safe” band where there are no mobile systems and noted that other space agencies, including those in Canada and China, have taken similar courses of action.

Google Requests 76-77 GHz for ‘Secret’ Experimentation
Tammy Parker reports Google plans mystery experiments at 76-77 GHz in an article on FierceWireless.com. “Google filed a highly secretive application with the FCC for an experimental radio authority, via which the company aims to test technology in the 76-77 GHz millimeter-wave band. That spectrum is authorized for short-range radar applications, including vehicle radars.” Consulting engineer Steven Crowley uncovered the filing and wrote about it on his blog. Google asked the FCC to treat certain information as confidential.

Google filed for two separate transmitter types, operating at low power in the 76-77 GHz band using FM and 8-PSK modulation.

The application sought authorization for testing across the United States and since the band is used for short-range vehicular radio the experiments may be tied to its self-driving car efforts.

More information is available on the Steven Crowley blog and in Google's FCC filing.

Comments and RF related news items are welcome. Email me at dlung@transmitter.com.

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.