RF Shorts - Sept. 16, 2011

More LightSquared News
There are several new stories about LightSquared's problems with GPS interference. FierceWireless.com author Phil Goldstein writes LightSquared makes more changes to network plan to appease GPS community. The article says LightSquared will limit the power of its terrestrial base stations to −30 dBm. It's hard for me to see how the system will work at power levels that low.

"According to a LightSquared official who spoke to reporters, that power level, as measured 50 meters from the base station, will not degrade the performance of GPS devices," Goldstein said. "In fact, in tests only two GPS receivers were operating above that threshold and their performance was not degraded. The official said that LightSquared's operational performance and business plan will not be affected by the change. By 2015, LightSquared will increase the power level to -27dBm and by 2017 it will increase it to -24 dBm."

LightSquared will also reserve 4 MHz chunk of spectrum for precision GPS applications.

According to the GPS Coalition, "To be clear, this proposal may be headed in the right direction, but there are still many questions and many concerns to many users."

It noted that GPS interference "must be responsibly, constructively, and completely addressed before LightSquared moves ahead," further adding that "even after three tries, there remain substantial gaps in what LightSquared has offered."

FierceWireless.com has a follow-up story by Sue Marek who writes LightSquared exec says GPS issue will be resolved within in month. The article focuses on LightSquared's deal with Sprint and also discusses its plan to protect high-precision GPS users.

For the politics behind LightSquared's proposal, see Cecilia Kang's article in the Washington Post, GOP decries FCC's conditional approval of LightSquared wireless plan.

Kang writes:

"At a House hearing Thursday, Republicans criticized the FCC for not using its own engineers to examine whether LightSquared's technology posed interference issues. The agency relied on tests run by the company and the GPS industry. Separately, in a letter, Sen. Charles E. Grassley (R-Iowa) said the FCC has refused to answer his questions or hand over e-mails and other correspondence between LightSquared and the agency."

FCC Permits MDCL Control Technology at AM Stations

Readers may be interested in a FCC Public Notice announcing the Media Bureau will permit AM stations to MDCL technology. Modulation Dependent Carrier Level algorithms allow more efficient operation of high power AM transmitters; however, their use previously required a waiver of Section 73.1560(a) of the FCC rules setting upper and lower limits for an AM station's operating power. The Public Notice has details on MDCL, its impact on power levels and companies using this technology.

TV Antennas sell out in parts of Canada

Web site thespec.com has posted an article this week that reports on the increased interest in antennas following the recent Canadian DTV transition. Marc Saltzman writes As TV goes digital, antenna sales boom.

The article offers this quote from Jeff Bayly, owner and operator of Ottawa-based OTA Canada: "Everything went bananas about two weeks ago when stations switched from analog to digital, and sales are just as strong [now]. We recently got shipment of 50 to 60 antennas and sold out right away, both in our storefront and online, but we've since brought in more inventory." Other retailers mentioned in the article tell similar stories.

Devices such as Channel Master TV are likely to make off-air TV attractive for a wider audience both in the United States and Canada.

Comments and 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.