RF Shorts for Nov. 1, 2012

Delay Seen in Move to Tokyo Skytree Transmission Platform

The transfer of broadcast transmissions from the Tokyo Tower to the Tokyo Skytree may be delayed past the original January 2013 date due to an unexpected level of radio interference. According to Rocketnews24.com, in an English translation of a story originally published in Japanese by Mainiche Select News, “Skytree is over 200 meters taller than Tokyo Tower, a height that towers over the tallest buildings so that radio signal interference from surrounding buildings would, in theory, be greatly reduced. However, NHK and other private broadcasting companies cooperated in testing signals off of Skytree to get a sample of what areas could receive them. Because the radio waves were too strong, or because of antenna placement, some households received no signal, which had nothing to do with the direction or area they were in.”

NHK needs to conduct more tests to determine what is going on with the Skytree transmissions. The article has this quote from an NHK executive, who stated “…the January transfer from Tokyo Tower to Skytree is not possible. Unlike the change over from analog to digital broadcasting, the transfer will take place in one night and testing of reception transmission has to be completed. It would be nice to be finished by May, but the excess cost is enormous.”

Wal-Mart Now Selling Boxee TV

Bloomberg's Mark Milian, in an article published Wednesday on Businessweek.com, writes Wal-Mart to Sell Boxee TVs Challenging Apple and Roku. “Starting tomorrow, the world’s biggest retailer will exclusively sell the new $98 product, called Boxee TV, in more than 3,000 U.S. locations during the holiday season. Wal-Mart will set up displays and send out marketing materials for the device, a small black box with a remote control that can access free TV broadcast channels as well as Internet content.”

Avner Ronen, Boxee's CEO, said, “It’s going to be a big launch for us. There’s a big difference between having your product being carried by retailers, where it sits on the shelf, and getting real marketing behind it.”

As I previously reported, the Boxee TV ships with an antenna for off-air TV reception. 

How Curiosity Phones Home

The Sydney Morning Herald describes communications systems used by the Mars rover in Brian Palmer's article Curiosity phones home: how the Mars Rover stays in touch. Palmer writes, “To get its messages to Earth, Curiosity first sends information to a pair of orbiters, Odyssey and Reconnaissance, that were sent in 2001 and 2005, respectively, to analyze Mars from a distance and are constantly circling the planet. (The Mars Express orbiter, operated by the European Space Agency, is also available if necessary.) The antennae on the orbiters are more than 1,300 times as powerful as the antenna on Curiosity. The rover waits for the orbiters to pass overhead to ship its messages, usually around 3 p.m. and again at 3 a.m.” Multiple receive sites are required on Earth, as Palmer explains, “… [as] the agency can't always use the same antenna on Earth, which might not be facing Mars at the right moment. Instead, NASA uses the Deep Space Network, a system of antennae in the Mojave Desert, Spain and Australia.”

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.