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RF Shorts – Oct. 8, 2010

I found several interesting articles this week about big antennas.

Karl Streeter's article Historic 'Mars antenna' in Mojave Desert undergoing major remodeling in the Los Angeles Times describes the massive antenna, which is located 35 miles north of Barstow, and 30 minutes from the nearest highway: "Deep Space Station 14 (informally dubbed the Mars antenna because its initial task in 1966 was to track a spacecraft after it flew past Mars) spreads from the ground like a looming, 10-story poppy. Its most eye-catching element is its parabolic dish, which stretches nearly the length of a football field and weighs, struts and radio equipment included, nearly 2,000 tons."

Sky and Telescope describes big antennas in My "Backyard" Radio Observatory. These antennas include a zenith pointing dish with an aperture of 220 feet and a fully steerable antenna with a diameter of 150 feet located at MIT's Haystack Radio Observatory.

"Amateur Radio Operators Connect to Giant LORAN Tower" by Jack Fichter in the Cape May County Herald talks about the adventures of the Cape May County Amateur Radio Club. The article, other than mentioning that the tower was 625 feet tall, had no technical details on the operation, but I'm assuming most operation was on 160 meters.

Thomas Hazlett, readers may remember, is no friend to broadcasters. In the article Shooting Blanks on Wireless Policy this week in the Financial Times he writes, "Shifting all the 'Aunt Minnies' to cable or satellite (more than 90 percent of U.S. households have already moved) would cost pocket change in comparison to the value of a free and clear TV band for new services: credible economic estimates start at a 30 to one social value gain."

The local oscillators in TV receivers generate an infinitesimal amount of RF compared with cell phones that are in constant communication with base stations. Would a move away from watching TV on receivers to using transceivers (cell phones and smart phones) to stream video lead to an epidemic of brain cancer or worse? In the article Brain cancer tied to heavy cellphone use in the Toronto Star, Georgetown University researcher Devra Davis says, "Frankly I think we have about three years to get on top of this or we face a global epidemic. I've looked at the totality of the evidence, extensive exposure literature on whole animals and cell cultures. There's clear evidence cellphone radiation causes a variety of damage to the brains of animals which is documented in my book."

Sify news also reported on Davis' research and quoted her as stating that "All the research shows the same thing—if you take young men who are trying to become fathers, those who use mobile phones at least four hours a day have about half the sperm count of others." How long will it take for someone on the fringes to say the FCC's National Broadband Plan is part of a secret government plan to control population?

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.