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Greetings Afrik-ITers!

Ah, more radio... 8*)

A preface -- I'm no expert.  You techies out there should feel free
to jump in at any time... 8*)

Paul Chavez writes:

> This site may have some information of interest.
> http://wireless.oldcolo.com/

Interesting web site -- thanks for the referral.  Excellent
information, I think, for persons within towns or cities where the
local telephone network is problematic.

One of the web pages to which Mr. Chavez refers defines the "scope"
of the project, specifically saying that these frequencies will be
tested:

>  (902-928Mhz, 2400-2483.5Mhz, 5700-5850Mhz)

From Paul Chavez' story on MSNBC:

> "They had no capability to get their signals across town," Hughes
> said. "The solution was wireless."

The operative phrase there is "across town", meaning fairly short
distances, using wireless technology that is essentially line of
sight at very high speed.

Here in Washington I use comparable technology from the Metricom
company that permits me to paddle a boat around the Tidal Basin by
the Jefferson Memorial while netsurfing at high speed (28,800bps) on
my laptop -- just for fun -- ok, some of us have peculiar ideas about
fun... 8*)  But where else can you surf the net while surfing a
wave?

While this technology is excellent where there are transceivers in
close range, they do not appear to me to be suitable for long
distance communications to remote rural areas -- about which the
original poster from Ethiopia was concerned. Techies?  Any comments?

Here's what the manufacturer of the equipment used in the Mongolia
experiment says about its product (visit http://www.freewave.com):

> FreeWave Technologies manufactures and distributes spread spectrum
> wireless data modems out of its headquarters in Boulder, Colorado.
> The DGR Family Of Spread Spectrum Wireless Transceivers is capable
> of transmitting and receiving RS232 data over long ranges (20
> miles) and at high speeds (115KBaud). Yes, that's 20 miles with
> line of sight at 115 KBaud.

The frequencies used by many HF radios, as I understand it, are from
about 2 to 24 Mhz, with ranges of 1000 kilometers or more.  Details
at

http://www.info.usaid.gov/alnk/tech/radio/radiomem.htm

with links to the CODAN Company's very extensive notes on
implementing an HF radio network in Africa.  The objective in this
case is the connectivity of remote places -- rural areas far from
cities and telephone infrastructure, and definitely not line of
sight.

Cheers!
Jeff @ Washington

[log in to unmask]
http://www.info.usaid.gov/alnk
1111 North 19th Street Suite 210
Arlington, VA 22209 USA
Tel 1-703-235-5415  Fax 1-703-235-3805