[imc-tech-solidarity] [solaris]Radio E-mail in West Africa (fwd)

[evan@protest.net]

Might be an intersting way to get MST camps and other outlying places
online.

-evan

---------- Forwarded message ----------
Date: Fri, 18 Oct 2002 12:21:43 +0530
From: Ashish Kotamkar <ashish@mithi.com>
To: Solaris <solaris@sarai.net>
Subject: [solaris]Radio E-mail in West Africa

I came across this interesting piece on internet connectivity via high
frequency radio in western africa on the DigitalDivide list. Though this
finds its birth in Africa, I think it has some implications for rest of the
world especially developing countries. Its longish so I suggest you visit
the site for the complete article. Hope you enjoy it.
Warm regards,
Ashish Kotamkar (ashish@mithi.com)
===============================================

Radio E-mail in West Africa: The Complete Version
http://www.linuxjournal.com/article.php?sid=6299

Deep inside the warm green interior of Guinea, centered in the frontal lobe
of West Africa, field personnel in the widely scattered village-towns of
Dabola, Kissidougou and Nzerekore now enjoy access to regular internet
e-mail, directly from their desktops. Here we have bridged the digital
divide, and there isn't a telephone line or satellite dish in sight. Instead
we are moving the mail over distances of hundreds of miles--over jungled
mountains and high palmy savannahs--through wavelengths of high-frequency
(HF) radio. Our project is called Radio E-mail, and here is its story.

The Republic of Guinea is a cashew-shaped nation with Atlantic view
property, 10 degrees north of the equator in west West Africa. It is a
beautiful and resource-rich nation, with an total land area about the size
of Oregon. As far as African countries go, Guinea is a calm pocket of peace
and stability, and it generally doesn't attract a lot of attention from
beyond its own borders.

But Guinea has quietly played a heroic role in the theater of world events
in recent years. It provides a safe and welcome refuge for as many as half a
million people displaced by brutal wars and civil upheavals in the
neighboring countries of Sierra Leone and Liberia.

The International Rescue Committee (IRC) has one of their largest operations
in Guinea, providing services and support to a population of up to 200,000
refugees quartered in many camps established throughout the country. I
became involved with IRC when my wife accepted the position of Country
Director for the program in the summer of 2001. Soon we were traveling on an
inspection tour of the camps, making the long road-trip to visit the
program's three field offices up-country. Our first destination was a
distant and dusty village, delightfully named Kissidougou--frequently called
Kissi in the local vernacular.

Traveling outside the capital city of Conakry, one immediately finds that
Guinea has little infrastructure, especially in the way of electrical grid
and telecommunication systems--to say nothing of Starbucks and broadband
access to the internet. So IRC field offices must provide their own
infrastructure: diesel generators for electricity and high-frequency (HF),
two-way radio sets to communicate with other offices and mobile units, up to
hundreds of miles apart.

Expecting this isolation and general lack of connectivity, I was quite
astonished when we arrived in Kissi. Here I found the radio operator using
his equipment to make a binary file transfer from his desktop PC to another
field office, wirelessly!

This capability surprised and intrigued me. On top of the operator's radio
set, connected to the serial port of his PC, sat a dingy black box simply
labeled 9002 HF Data Modem. I noticed the operator used a proprietary,
MS-DOS program to make his file transfers, but I immediately began
wondering: if this device is truly some kind of modem, moving binary data
over the ether of radio, why couldn't we set it up with Linux and network
with PPP connections as well?

After a little research and testing, I soon confirmed this equipment could
indeed form the basis of a wide area network, providing full access to
internet e-mail via the Conakry office for all personnel in each of the
three field offices. Moreover, since IRC owned most of the equipment
already--and since we would be using Linux and other freely available,
open-source software--the system could be implemented at negligible cost,
with no increase in operating expenses. For the price of some network cards
and category 5 cable, we could connect our bush offices to the rest of the
world. I developed a design and specification for the system, and the
project we call Radio E-mail has been continuously operational since January
2002.


HF Goes the Distance
If you have been making the move to wireless lately, most likely you are
working with the microwave, high bandwidth frequencies of 802.11b. If so,
you know that on a clear day you maybe can get a line-of-sight connection
out 10 miles or so. That surely won't do for the vast distances and wild
terrain we need to cover in rural Africa.

HF radio is another animal. Its longer waves roll out across the landscape,
reflecting off the ionosphere to follow the curvature of the earth. This
gives HF signals a range in the hundreds of miles. From Conakry to
Nzerekore--IRC Guinea's most distant field office--HF easily covers a
straight-line distance of over 375 miles (600 kilometers.) The road that
sometimes connects these two points is, of course, much longer--a
gut-slamming, spine-jamming, two-day punishment for the damned.

So the great advantage of HF is it can go the distance, leaping the
obstacles in its path with aplomb. Now for the bad news: where HF wins the
wireless game in range, it loses its pants in data capacity. If 802.11b is
considered broadband, think of HF as slim-to-none-band. The radio modems we
are using here are speced at an anorexic 2400 baud!

And wait, it gets worse. Two-way radio is the classic half-duplex medium of
communication; that is, you are either transmitting--push to talk--or
receiving, not both at the same time. This, plus the robust error-checking
protocols implemented by the modem hardware itself, means the actual link
experience is more on the order of 300 baud. Does anyone remember 300 baud?
Unless you measure your patience with radio-carbon, your dreams of remote
login sessions will be dashed and splattered. As for on-line browsing, chat,
video-conferencing and the like, well, best to not even think about it.

Yet for classic store-and-forward applications like text-based e-mail, the
bandwidth limitation of HF radio is workable. We simply need to pay close
attention to our configuration and try to optimize as much as possible. With
HF radio, every packet is precious. .....

<snip>

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