Doug Lung /
RF Shorts for Sept. 6, 2013
A review of RF-related news during the past week
e2v Uses RF to Stop Vehicles
Most broadcast engineers recognize e2v as a manufacturer of those magical IOTs which take a few hundred Watts and amplify it to 20,000 Watts or more. Tubes for TV transmission are only one part of e2v's business, as their press release e2v to Showcase Capability to Stop Vehicle Engines Remotely, at DSEI 2013
As you may have expected, this is done using large amounts of RF. E2v says, “The RF Safe-Stop technology can immobilize a variety of motor vehicles and small boats, causing the engine to shut down, typically in less than one second, with a non-destructive effect.”
In case you are worried that the driver might end up cooked in the process, e2v said it has conducted “extensive testing and signal conditioning to ensure that the RF field falls within international guidelines, making it human-safe.”
More Input on the Spectrum Shortage Issue
Roger Entner has an analysis of the value of spectrum at Fiercewireless.com in The misguided and misleading spectrum discussion
. He writes, “Something that seems to have been forgotten is that the spectrum crunch in the United States does not exist in rural America. It only exists in the densely populated urban areas. Rural America is as well covered as it is profitably possible to cover with the industry's existing spectrum portfolio of 700 MHz to 2.5 GHz.”
Entner confirms my belief that the 600 MHz spectrum the FCC and Congress want to take from broadcasters isn't the best choice for urban areas.
Entner explains: “Where we have a problem is in the densely populated areas where the spectrum propagation characteristics of high-band spectrum are preferred because the focus is on expanding capacity, not coverage. In fact, the very properties that make low frequency spectrum so useful for covering large, flat, lightly populated areas become handicaps in the densely populated urban canyons where the spectrum crunch is happening.”
He attributes this to both physics and the design of wireless broadband networks.
“In the densely populated areas, carriers have to deploy more and smaller cell sites to handle exploding usage patterns. More cells sites means more opportunities for interference, especially as the cell sites are located in closer and closer proximity to each other due to limited locations for cell site deployment in urban markets. In this scenario, high band frequencies are prized because they give the networks the depth of capacity the carriers need, yet create fewer interference issues than low band. Further, whether low band can cover more miles with fewer sites is irrelevant in the urban markets.”
Entner's article outlines the folly of trying to forecast the value of spectrum, noting how far off estimates were of the value of Leap Wireless' spectrum. The implications for this for the Incentive Auction process should be obvious.