Public Power

for today's wired world

technology continued...

Cable companies and manufacturers of phone equipment went to work on developing ways to retrofit the old copper and coax in a way that was not dependent on plain old telephone dial tone. The result was cable modems for coax and DSL modems for copper phone wire. As retrofits, both technologies faced serious limitations, and like “dial-up”, their life span is limited to the next decade or so. The capacity of coax and copper simply tops out because of the way electrical impulses travel down a metal wire longer than a few hundred feet. It appears that the topping out may be in the range of five million to ten million (10,000,000) bits per second. Two things tend to keep the capacity below that. The cable system is designed like a water system with consumer pipes tapping into a bigger pipe in the alley that then taps into a hierarchy of bigger pipes that eventually tap into the water tower. The system works well, but can really vary if a lot of the neighbors turn their lawn sprinklers on at the same time. A signal that is fast at times can be murderously slow at others. Likewise, a DSL signal which may be able deliver 5,000,000 bits per second at a range of a block may struggle to deliver a tenth that at the 3 mile point before it finally fizzles out. Splices in copper wire, corrosion in junction boxes, and insulation that has been deteriorating for decades are among the things that can plague DSL.

 

Two other technologies have emerged as delivery vehicles. They appear to also be able to offer service until fiber to the door becomes universal. Both are emerging technologies and come with considerable fanfare from the FCC.

 

The first is wireless. Wireless comes in two flavors, licensed and unlicensed. A licensed wireless operates on one of several frequencies designated for various purposes by the FCC. It has the advantage of being able to use higher power transmission stations (called Access Points or AP’s for short) and exclusivity of use within a licensed area. It has the disadvantage of the cost of the license, which can range from the millions of dollars for some commercial uses to fairly low cost for some civic and public safety uses. It generally requires specialized, and sometimes expensive, end user equipment. That cost can be a barrier to its deployment. The other flavor of wireless is unlicensed. It initially operated basically at a handful of narrow channels at about 2,400,000,000 cycles per second or 2.4 gigahertz (2.4gHz). No license is required, but the power, thus the range, allowed is very low. That means the useful distance is very limited, as is its ability to penetrate obstacles, walls, or trees. Never-the-less thousands, if not hundred of thousands, of different types of devices were placed in use at the 2.4 GHz frequency. A few examples of these are wireless computer mice and keyboards, TV remotes, extension phones, wireless computer cards, light switches, garage door openers, microwaves ovens, and even Christmas lighting displays. The result is millions of cheap, consumer devises broadcasting in mass. These devices compete with each other to find a niche in one of the limited number of channels in 2.4 GHz range and their collective aura glows across the channels. Because signal strength generally deceases with the square of the distance, a closer unit is in a position to overpower a more distant one. 2.4 GHz technology has one distinct advantage to other wireless technology distributing Internet signal. The receivers are commonly built into computers or can be added to a computer for a very low cost. This significantly reduces consumer barriers to use of the technology. However, such cheap transmitters send out a wimpy signal resulting in limited signal range and quality, regardless of the quality or power of the AP on the tower with which they communicate. For a distribution system based on unlicensed 2.4gHz the access points (AP’s) need to be spaced close enough together to be able to “talk” through walls and trees with these wimpy computer antennae, else more expensive antennae that boost the signal from the AP’s need to be mounted outside on the consumer premises to relay the signal to the computer inside. In an experiment in Columbus, Nebraska, an AP was mounted on the roof of a building at 1765-26th Ave. With the leaves off the trees and a clear line of sight, a laptop computer did not lose connection until it was just beyond the east steps of the courthouse, a distance of about 1,000 feet. However, a connection could barely be maintained one block (300 feet) to the east of the AP when the signal had to penetrate 2 plaster walls. Preliminarily, it would appear that for a 2.4gHz wireless grid to really be convenient and useful there might need to be about one well-placed AP per block and there might not be a pole just in the right place. Without sufficient penetration power, the usefulness of the technology is limited as is its viability as a competitive vehicle for the delivery of alternative voice service. 2.4 GHz wireless speeds vary and may be as high as 54,000,000 bps at very close range. More commonly the speed runs below 11,000,000 bps. So, it is comparable to DSL or Cable modems.


    more >

latest news

11/13/2007
Nebraska petition to lift BPL ban faces dramatic obstacles.   Read more.

10/21/2007
Our petition drive is picking up more and more attention as a real good idea.   Read more.

12/19/2006
Task force vies to set Nebraska BPL ban in stone.   Read more.

12/06/2006
Nebraskan Group Seeks Vote on Municipal Broadband Rules.   Read more.