[Cu-wireless] Re: tentative wireless penetration table

[Jon Dugan]

Paul Riismandel <p-riism at uiuc.edu> wrote:
> Are all basic wireless networks using 2.4 Ghz?

  All the 802.11b (11Mb/s) (and the older 802.11 (2Mb/s)) networks use the
  2.4GHz band.  I believe 802.11a (45 Mb/s) will use the 5.8GHz band.

"Zachary C.Miller" <wolfgang at wolfgang.groogroo.com> wrote:
> I'd like to know whether the "wireless ethernet base stations" get
> more range than the individual wireless cards or whether they are just
> simply routers with standard issue cards in them.

  In terms of power and the actual radio many companies use the same PC card
  both for the AP and the client side.   This is true of the Cisco 340 and 350
  series and the Lucent AP-1000.  (As is the case with the Apple AirPort and
  Lucent RG-1000 as was previously mentioned). The Ciscos use external
  antennas, whereas the Lucents use the integral PC card antennae.

  I've taken apart a Cisco AP 340, and it has an unlabelled PC Card attached
  by a PC Card connector to a printed circuit board.  It has two antenna
  cables running from the PC Card to the antenna connectors on the outside of
  the box.

  Here's what I've been able to glean in terms of power:

    Power (mW)  Description
    ----------  ----------------------------------
    100         Cisco 350/Aironet 4800
    50          Lucent Bronze/Silver/Gold
    30          Cisco 340   

> I think propagation is going to be all about custom antenna design.

  I agree, although having more power will definitely be of value as well.
  I've been reading up on antenna design.  Here's a few useful links:

    http://users.bigpond.net.au/jhecker/  
    http://205.159.169.11/reference/antennas/

  Also, the ARRL Antenna book is a great resource.  Grainger has several
  copies.
 
  Paul Wefel and I have built a pair of the helical antennas described by the
  first URL.  We got a chance to try them out earlier this week, and they
  actually seem to make quite a difference.  I don't have any quantitative
  data at this point.  We're going to build a couple of the omnis described at
  the second URL.

  One thing that I am concerned about is trees.  Don't get me wrong, I love
  trees, but they are going to present a real challenge to building the
  backbone point to point links.  We're going to need to either put up some
  towers or find someone who will give us access to some tower space.

  [Random additional information]
  I am typing this message at the Holiday Inn in Urbana using a Lucent Silver
  card to talk to the 802.11b wireless network that we have setup for the
  conferences we have here this week.  Pretty standard.  
  
  The cool part is how we got from NCSA to here.  We have a 5.2/5.8GHz
  unlicensed 100Mb/s radio link.  One end is a 2' flat panel antenna on the
  WILL tower (at Campbell Hall) and the other is anther 2' flat panel antenna
  on top of the Holiday Inn.  The radio is a Tsunami 100 radio from Western
  Multiplex (www.wmux.com).  The radio is a 100 Mb/s ethernet bridge.  It uses
  two seperate channels to provide full-duplex operation.  

Jon
-- 
Jon Dugan             |  Senior Network Engineer, NCSA Network Development
jdugan at ncsa.uiuc.edu  |  57C CAB, 605 E Springfield, Champaign, IL 61820
217/244-7715          |  http://www.ncsa.uiuc.edu/people/jdugan