From: Eirikur Hallgrimsson (eh@mad.scientist.com)
Date: Sun May 28 2000 - 21:38:38 PDT
You've probably heard all the schemes for blanketing Africa with
cheap web-tablets. Five years ago it was India and Apple Newtons.
The hardware is still several orders of magnitude too expensive.
The network infrastructure isn't there, and the software usability
(especially in local languages which may not have written versions)
is REALLY not there.
Contrast shortwave. Anywhere in the world, a $5.00 radio and a coil
of wire will bring in the news in most major language groups. There
are language lessons, and all kinds of educational stuff, too. And
more propaganda than you can shake a stick at, of course....
"Wait a minute, Eirikur! Those radios you pointed Carey at start at
$200.00!" Yeah, but I was assuming that she wanted to hear the
people's popular front of Paraguay broadcasting on battery power from
their hidden trailer which they have to move nightly. FOB Taiwan, a
single-band shortwave radio is about $2.00, and the Taiwanese make
a little money at that price, I think. A single-band shortwave is
exactly the same animal as a cheap AM-only transistor radio. 4-5
transistors. No chips, no digital at all. The Chinese
mainland and or Malaysia could probably get the price down further if
there was demand. You don't get solar-recharging at these prices,
sad to say. You can get down to 0 transistors and no batteries
(this is the classic crystal radio), but tuning and sensitivity
limitations generally drive toward the transistor approach. A
surface-mount design that included the solar cell and the piezo
speaker might be a great EE student project.
One band, the international broadcast band at 40 meters (near 6.0
Megahertz) is all you need, and the radio doesn't have to be very
sensitive because everyone transmitting on that band has giant
towers.
At 40 meters, a 1/4 wave antenna is 10 meters--easy to carry in a
pocket in case you are in a bad area for reception. Actually, any
metal object like a wire fence (good in rural areas) can be tried as
an antenna.
You can pull voices out of the air, with a pocket-sized analog device,
anywhere on Earth. It's a miracle that goes unnoticed. That
Marconi guy really had something.
Eirikur
This archive was generated by hypermail 2b29 : Sun May 28 2000 - 22:39:44 PDT