It is called scotoma. The mind sees what it wants to see. - DaVinci Code

TechWorld says telecom regulator Ofcom wants to make high-power WiFi equipment legal, proposing to raise the power limit in the UK from 2W to 4W (in the 5.8GHz band) and raising the power limits by a factor of 100 in the unlicensed 2.4GHz band (from 100 mW to 10 Watts).

The high-power WiFi kit is intended to meet the needs of rural wireless, so Ofcom’s main concern is that it does not get over-used in urban areas and swamp the city’s airwaves.

This could mean a registration scheme for high-power WiFi (much like the “light licence” scheme in the 5.8GHz band). More intriguingly, it could mean a system that makes the high-power kit “location aware” so, apparently, it will know where it is, and only work at high power if it’s in an approved area.

Ofcom has begun a consultation on the following options:

• Allow the increased power anywhere
• Allow the increased power in rural areas with location awareness to minimise interference.
• Allow increased power in all but large and major urban conurbations, with a registration scheme

It begs the question…why did the FCC decide to limit the unlicensed mid-5 GHz band (from 5.2-5.7 GHz) to 100 mWatt. The 5.8 GHz band allows much higher power 1W/4Watts (omni/p2p).

Whose side is the FCC is on? Could it be the big telcos?

FCC regulations say a 2.4 GHz client can use a 30 dBm transmitter with a 6 dBi antenna. For point-to-point links power can be increases significantly. The idea here is that PTP links don’t create broad interference with a narrow pencil beam.

For every 3 dB increase in antenna gain, the transmitter power output must be reduced by 1 dB. Refer to the following table:

FCC Power Authorized for 2.4 GHz Point-to-Point

According to FCC Part 15.407, 5.8 GHz UNII-3 wideband digital fixed point-to-point transmitters may use a 30 dBm transmitter with directional antennas with up to 23 dBi gain without any corresponding reduction in transmitter power. Maximum EIRP is 53dBm (200 watts).

FCC Power Authorized for 5.8 GHz Point-to-Point

FCC regulations for 5.8 GHz state that you can have an effective EIRP up to 200 watts (in Pt-to-Pt) using a 30 dBm (1 watt) transmitter with directional antennas with up to 23 dBi gain without any corresponding reduction in transmitter power. Combining a (+30dB) radio (1 watt) with a (+23dB) antenna, totals (+53dB).

The joint Mexico-U.S. effort to build a monster telescope atop a dormant volcano southeast of Mexico City is largely funded by the U.S. Defense Department and aimed at developing technology for space defense, say some experts. About 60 percent of the US$100 million (and climbing) cost will come from Mexico. The radio telescope, designed to be the largest of its kind in the world, has faced a host of construction challenges.

“It is a very high-powered, focused radar beam that could be used to find an enemy object out in space and, having found it, zero in on it,” said Philip Coyle, U.S. assistant secretary of defense in the Clinton administration.

While the Large Millimeter Telescope´s primary mission is to use radio waves to probe the origins of the universe, some Mexicans believe its military link teeters on the edge of unacceptable territory for a nation that prides itself on staying non-aggressive on the world stage.

Peter Schloerb, who oversees part of the project for the University of Massachusetts at Amherst, said there could be defense applications for the radio-telescope research, but said the Pentagon has had a hand in many types of research.

“I am an astronomer. I am not a weapons scientist,” he said. “Nobody in their right mind would build some kind of a secret weapon in the country of Mexico. That is just not happening. There is a lot of basic research that has been funded by the Department of Defense.

Maybe the DOD will bring in Woody Norris to create Audio Beamforming on a massive scale or simply heat up satellites in the 85-107 GHz atmospheric hole. And how about MIMO? Let’s get Trex on this.

Related DailyWireless stories include; WiMAX Distance Record, New Long Shot Record - 137 miles?, New Wifi Record - 125 Miles!, Cheap Long Shots, Intercontinental WiFi and Intergalatic Long Shots.

Posted by Sam Churchill on Tuesday, July 25th, 2006 at 8:19 am.