RF Shorts for Dec. 20, 2013
Broadcasters Condemn Ofcom’s White Space Plan
Rene Millman reports on opposition by U.K. broadcasters to Ofcom's plans to use TV white spaces to launch wireless services in the article Broadcasters pan Ofcom over white space disruption to Freeview
on Recombu.com. Industry body, Digital UK, owned by the BBC, Channel 4, and Arqiva, sent a response to the plans, saying that there were a number of errors in its technical plans. This prompted broadcasters to raise a number of concerns about Freeview reception being seriously affected. The Digital UK response document stated: “Based on the technical parameters detailed in the consultation, certain assumptions in the modeling have the potential to significantly affect DTT coverage, which could ultimately disrupt TV viewing to noticeable levels.”
For more details on Ofcom's white space tests, see my article Ofcom Okays Testing of New Applications in White Space Spectrum--Trials include remote sensing, highway information and rural broadband
in the Oct. 7, 2013 RF Report.
NASA's Deep Space Network Turns 50
On Dec. 24, 2013, NASA's Deep Space Network, the world’s largest and most powerful communications system for communicating with spacecraft, will celebrate its 50th anniversary.
The JPL news release NASA's Deep Space Network Turns 50
says, “On Dec. 24, 1963, the Deep Space Instrumentation Facility officially morphed into the Deep Space Network and quickly became the de facto network for any planned missions into deep space. Three antenna complexes were established around the globe, spread out at roughly 120 degrees of longitude so that even as Earth rotated, spacecraft would always be above the horizon of at least one complex. While some of the communication facilities have moved over the decades, today the three complexes, which operate 24/7/365, are located in Canberra, Australia; Madrid, Spain; and Goldstone, Calif.”
DSN Project Manager Al Bhanji of NASA's Jet Propulsion Laboratory, Pasadena, California, said: “Today, the DSN supports a fleet of more than 30 U.S. and international robotic space missions. Without the DSN, we would never have been able to undertake voyages to Mercury and Venus, visit asteroids and comets, we'd never have seen the stunning images of robots on Mars, or close-up views of the majestic rings of Saturn.”
Communications technology is much different now than it was in 1963, so it’s interesting to speculate on what the future might bring. The JPL news release offers this insight: “The future of the Deep Space Network looks bright, with optical communications on the horizon to augment the traditional RF-technology (radio waves moving at the speed of light). Optical communications, when operational, will provide a dramatic increase in data return from science missions; the potential bandwidth carried by an optical communications laser beam is far greater than with traditional radio frequencies. In fact, the DSN team envisions the day, not so far off, when, in addition to returning photos of robotic wheel tracks in the dusty surface of Mars, they will be streaming video to a wide-eyed public as the first humans leave their own footprints on its surface.”
Al Banji commented: “In 2063, when we celebrate the Deep Space Network's 100th anniversary, we can imagine that we might be recalling the amazing days when our antennas streamed high-res video as the first humans stepped onto the surface of Mars, or that day when we discovered a new living 'Earth' orbiting a distant star.”
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