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How do Wireless Range Expanders work?

written by: Daniel Barros•edited by: Lamar Stonecypher•updated: 5/31/2009

Continuing our coverage of Wireless repeaters and expanders, we take you in-depth on what a wireless range expander actually does and how.

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    Expanding on Up

    I touched base on this slightly in my “How to Configure a Wireless Repeater” article, but let’s go a little more in-depth as to how a wireless range expander or a signal repeater actually works.

    First, you need to analyze the router you currently have to understand what’s happening. A modern wireless router takes the Internet signal it receives from the modem and splits it amongst various different computers using sophisticated technology. However, this is only if the router is wired, because when it’s wireless, the situation changes a little bit. Rather than just being a cable splitter that takes the original signal and gives it to a few Cat5e connectors, it sends the signal up into a radio antenna that then broadcasts the signal continuously in all directions.

    The radio antenna takes this electrical signal and transforms it into electromagnetic radiation that can permeate through the air. This is where things end if you just have a computer connecting to a router wirelessly. The computer translates a command from an Internet browser into a radio signal and transmits it out to the router; the router then takes the signal and pipes into the modem which accesses the Internet, which accesses the specific server requested. The server responds with a string of information that is then piped back into the modem, which is piped back into the router, which is then broadcast out to the PC, which then displays the webpage.

    If this sounds complicated, it really is rather simple – the trick to understanding why it takes seconds and not days to load a webpage is to remember that electromagnetic waves travel at the speed of light inside cables and through the air.

    But that’s only if you have a router and nothing else. Throw a repeater into the mix and the process changes up slightly.

    Now, we have a router broadcasting a signal out the same way as before, but rather than having a computer pick it up, a wireless repeater picks up the signal and it undergoes a sort of powering-up inside the hardware. When the repeater receives the signal, it is directed into the other, more efficient transmitter that again transmits in a spherical radius to any computers within range.

    The process I described above happens again, only this time, rather than going directly to the router, your PC picks up the boosted wireless signal from the repeater and sends out the radio signal described above to the repeater rather than the router. The repeater then sends the signal back to the router and the relay begins all over again.

    This is the same technology that allows satellite radio signals to be received without having to have a huge dish in your car. In places where there may be poor coverage due to being on the edges of the satellite's coverage or among tall buildings, satellite radio providers locate repeater stations that pick up the signal from the satellites and relay them to the much smaller receivers in cars and homes. Several of these ground repeaters are in use throughout the country.

    The problem with wireless repeaters is that the communication, which unlike satellite radio is two-way, is being degraded over-the-air twice over. This typically means shoddy connections and slower loading times. The degradation is seen specifically in one of Buffalo's repeaters, which have a "A significant (over 50%) throughput reduction" (source: http://www.dailywireless.org/2002/12/21/repeaters-and-wireless-distribution/), this means that the signal is halved by the time it actually reaches your antenna on your computer.

    Why doesn’t this happen with a radio repeater? To amplify the signal, the signal strength from the repeater tower is much more powerful to the receiver than the original transmitting source - and it's on the same frequency, of course.

    Now look at your wireless repeater – in order to make it palatable to consumer tastes, it must be tiny – and this means losing that incredibly powerful antenna I mentioned earlier.

    And there you have it – a repeater is a simple piece of technology that is often misunderstood for something much more complicated. Just further proof that tomorrow’s tech marvels are often found in repurposing technology from the past – in this case, the famous radio towers that litter the American landscape and the newer radio repeaters that allow for Satellite radios to exist.