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RF Shorts - July 13, 2012

WLS-TV Removed Antenna From Willis Tower

If Chicago television viewers looked up at the top of the Willis Tower building last Sunday morning, they would have seen a helicopter removing WLS-TV's 4,000 pound Channel 7 antenna from the east tower. ABC7 news has details and video in Diane Pathieu's article Crews removed old ABC7 antenna from top of Willis Tower

Bonnie McGrath has here description of the antenna removal in her posting My view of antenna down – Channel 7 provides Sunday morning entertainment

Budget Cuts Hit Shortwave Broadcasting 

If you have a shortwave radio, you may have noticed the number of English-language programs has decreased over the years. Most recently, Radio Netherlands Worldwide closed its English service on Friday, June 29, 2012. Radio Canada International ends its shortwave broadcasts on July 24th. 

The Economist describes the trend in the article Shortwave radio – Tuning out – A cold-war stalwart goes out of fashion. It notes, however, that “Other stations are filling the newly empty spectrum. World Christian Broadcasting of Tennessee has built a new site in Madagascar which will beam multilingual music, news and religious programming to South America, Africa and the Middle East at an annual cost of over $3 M.” 

If the spectrum is no longer needed for broadcasting, could it be used for broadband? The Economist article notes, “Globe Wireless, an American firm, has long used shortwave for maritime e-mail service to thousands of ships. Although the data speeds (at only 2,400 bps) are not as zippy as a satellite link, the service is cheaper--and keeps going if solar flares or space debris hit satellites, says the firm’s boss, David Kagan. The shortwave voice may be old and hoarse. But it still dependably carries a message.” 

“Starfish Prime” Nuke Test EMP Danger Recalled

Discovery magazine's Bad Astronomy” page has an article on one of the ways satellite links could be knocked out in the article 50th anniversary of Starfish Prime: the nuke that shook the world. The article notes, “When the bomb detonated, those electrons underwent incredible acceleration. When that happens they create a brief but extremely powerful magnetic field. This is called an electromagnetic pulse, or EMP. The strength of the pulse was so huge that it affected the flow of electricity on the Earth hundreds of kilometers away! In Hawaii it blew out hundreds of streetlights, and caused widespread telephone outages. Other effects included electrical surges on airplanes and radio blackouts.” 

The article says the Starfish Prime detonation damaged at least six satellites, all of which eventually failed. One of those affected by the blast was the first communications relay satellite, Telstar. (See the article on its 50th anniversary elsewhere this week's report).