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PA2AGA > HDDIG 18.11.99 09:44l 189 Lines 6460 Bytes #-9680 (0) @ EU
BID : HD_99_294B
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Date: Wed, 17 Nov 99 23:13:32 MET
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From: pa2aga
To: hd_broadcast@pa2aga
Subject: HamDigitalDigest 99/294B
X-BBS-Msg-Type: B
They
currently run about $120 a node. Much cheaper than packets sent through
voice quality radios. These radios are very low power in comparison to
voice radios. 100 mW versus 10 Watts for example. This means that you
will have to service customers in cells. That is, a main master node, =
and
several client nodes. The master node would be high altitude, and =
clients
would be line of sight to it, inside of one mile or so. These master =
nodes
then need a backbone frequency to tie them all together. This has the
advantage that there are no radio adjustments performed by the client.
Look at www.proxim.com/symphony web page. I have two of these
cards going 4.65 (GPS measured) miles with amplifiers and parabolic
antennas. The U.S. laws are pretty easy. For every 3 dB over 6dB of
antenna gain, you have to reduce power by 1 dB from the 1 Watt maximum.
It is the Part 15 rules that apply to spread spectrum radios. This link =
is
using Proxim is 1.6 Mbps half-duplex. (but half-duplex spread spectrum
is nothing like half-duplex FSK). To see a typical client utilization, =
see:
http://www.usa-site.net/stats/www.usa-site.net.4.html
compare that to:
http://www.usa-site.net/stats/www.usa-site.net.5.html
which is a 70cm 9600 baud Internet gateway (mostly email and DX
cluster). This is an ISP I run out of my closet using Linux for people
who want 24 hour a day access at lower rates than 56k modems.
Steve
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<DIV>Shahbaz Chaudhary<CHAUDHAR@UMICH.EDU> wrote</DIV>
<DIV> </DIV>
<DIV>>I've read a few papers and intro. articles on packet radio and =
how it=20
can do<BR>>tcp/ip. There doesn't seem to be a lot of =
information on how=20
many people<BR>>are regularly using this to get on the =
internet. I=20
couldn't find much<BR>>information on how the costs compare to line =
modem=20
ISPs and didn't see much<BR>>about the distances/line of site=20
requirements.<BR></DIV>
<DIV> </DIV>
<DIV>It works for email down to very low baud rates. But email is =
not what=20
it was</DIV>
<DIV>10 years ago. 10 years ago, email was not MIME encoded to the =
extent=20
it</DIV>
<DIV>is today. People think very little about attaching pretty=20
backgrounds, MS-Word</DIV>
<DIV>and even spreadsheets to mail. The old paradigm of connecting =
to a=20
BBS</DIV>
<DIV>over packet and getting just plain email is almost over. I =
run an=20
internet</DIV>
<DIV>gateway and have a few users hundreds of miles away who access =
the</DIV>
<DIV>gateway at 1200 baud (about 30 baud effective through several node=20
hops).</DIV>
<DIV>They are often confronted by MIME encoded email, and not having the =
desire</DIV>
<DIV>to set up their own gateway, tend to just delete the mail =
unread. =20
It's too hard</DIV>
<DIV>to get the encoded mail and then import it into a browser or =
microsoft=20
product.</DIV>
<DIV>Plus it takes all day to download it.</DIV>
<DIV> </DIV>
<DIV>>It costs about $15 to $20 a month to get internet connection, =
so=20
perhaps<BR>>that's why packet radio hasn't proliferated. =
However, in=20
parts of the world<BR>>getting internet connection through standard=20
telecommunication media is<BR>>extremely expensive (if short phone =
calls are=20
expensive, an hour on internet<BR>>per day can add up).<BR></DIV>
<DIV> </DIV>
<DIV>Those same countries probably have laws that prevent radios from=20
being</DIV>
<DIV>used to bypass their utility.</DIV>
<DIV> </DIV>
<DIV>>If someone wants to set up an ISP (perhaps city wide, for a=20
fairly<BR>>large/congested city) using radio instead of=20
phone/xDSL/cable/etc., what<BR>>issues need to be addressed. =
What are=20
the limitations. For example, it<BR>>seems like someone using =
this=20
radio technology will be able to have a 24<BR>>hour connection, =
albeit a=20
slower one. However, that should be fine for an<BR>>average =
middle=20
class home outside of the rich/developed countries who<BR>>basically =
needs=20
email and maybe a little web access.<BR></DIV>
<DIV> </DIV>
<DIV>What you want to invest in, is spread spectrum modems. These =
are=20
ethernet</DIV>
<DIV>cards with an antenna jack. They have ethernet and radio=20
built-in. They</DIV>
<DIV>currently run about $120 a node. Much cheaper than packets =
sent=20
through</DIV>
<DIV>voice quality radios. These radios are very low power in =
comparison=20
to</DIV>
<DIV>voice radios. 100 mW versus 10 Watts for example. This =
means=20
that you</DIV>
<DIV>will have to service customers in cells. That is, a main =
master node,=20
and</DIV>
<DIV>several client nodes. The master node would be high altitude, =
and=20
clients</DIV>
<DIV>would be line of sight to it, inside of one mile or so. These =
master=20
nodes</DIV>
<DIV>then need a backbone frequency to tie them all together. This =
has=20
the</DIV>
<DIV>advantage that there are no radio adjustments performed by the=20
client.</DIV>
<DIV> </DIV>
<DIV>Look at <A=20
href=3D"http://www.proxim.com/symphony">www.proxim.com/symphony</A> web=20
page. I have two of these</DIV>
<DIV>cards going 4.65 (GPS measured) miles with amplifiers and =
parabolic</DIV>
<DIV>antennas. The U.S. laws are pretty easy. For every 3 dB =
over=20
6dB of</DIV>
<DIV>antenna gain, you have to reduce power by 1 dB from the 1 Watt=20
maximum.</DIV>
<DIV>It is the Part 15 rules that apply to spread spectrum radios. =
This=20
link is</DIV>
<DIV>using Proxim is 1.6 Mbps half-duplex. (but half-duplex spread =
To be continued in digest: hd_99_294C
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