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Re: STUPID DIGITAL RESPONSE



On Thu, 18 Feb 1999 MIKE_NASON asked:

> I know everyone has different ideas as to what's fun.... But could
> someone please explain to me the attraction to digital satellites? 

*** Today, with the internet and everyone using 33 to 56 Kb modems for
less cost than just a packet TNC, digital amateur satellites are of little
value.... ***EXCEPT***:

1)  In remote areas where you do not have internet access (for ham radio)
2)  In areas where you pay per minute for internet access (for ham radio)
3)  In Mobile and Portable operations anywhere

Couple this to the fact that many Hams only have time to play radio while
they are mobile (or portable), leads to my "cause-ce'le`b".  Which is:

   ***   We need to figure out better ways to use the AMSATS   ***
   ***    from mobiles and even from Handhelds.  We must go    ***
   ***       Satellite WIRELESS like "everyone else"....       ***

     Last week's APRS/MIR School tests demonstrated that a digipeater like
MIR for UI frames can easily digipeat brief position/status messages
from the Kenwood Data HT.  There are several initiatives that are underway
but we need more experimenters to help.  All of these concepts use a few
gateway ground stations to link the live Satellite links from mobile/hand
held users back into Internet Backbones for worldwide connectivity:

1)  Using the underutilized four 1200 baud Pacsats that can digipeat
packets from any TNC (with $3 mod).  All we need is a few dedicated ground
stations to track/receive these packets from hundreds of users.  The
worldwide APRServe Internet Backbone is already in place: TELNET to
199.227.86.221 port 23 to see it.  See WEB links below...

2)  Using the Kenwood HT via MIR (5 watts QRP via MIR when the MIR PMS is
not in use).  THis is only for SPECIAL events (or remote expeditions far
from North AMerica, Europe, Japan or anywhere where the MIR PMS is
otherwise in use).

3)  Using the Kenwood HT as a receive only station for the 9600 Baud
Pacsats.  By monitoring and capturing the PACSAT protocol, the remote user
can "receive" messages.  This capability needs some special handling and
ground stations, but CAN be done.  THe HT user only needs a small (1 foot
long) 3 element UHF beam to receive the data.  Tracking is trivial since  
pointing is very broad (easily over 90 degrees with the small antenna).

4)  Launching an AX.25 UI digipeater Satellite (see last weeks NATSweb
announcement.. and cancelation...)

In conclusion, we must explore ways to use our existing birds more
effectively for mobile travelers and we must make sure that future birds
anticipate mobile operations and do not just duplicate more BBS's in
space...  In a mobile environment, just conveying a SINGLE LINE
position/status and a few SINGLE LINE MESSAGES is all that is needed.

Think two-way Ham Radio worldwide message paging...

An amateur satellite in this kind of situation can handle HUNDREDS of
users per pass!  Instead of the few users (half dozen or so) that we see
on some satellites.

Already APRS permits transparent HT/Mobile data comms to over 80% of the
HAM population of the USA and some other countries (See coverage map
on page 19 of January QST).  Last night I was keyboarding with a Japanese
HAM walking down the street in Japan with nothing more than the Kenwood HT
in his pocket).  BUT the terrestrial APRS infrastructure only covers 25%
of the USA LAND MASS and NONE Of the oceans nor most of the rest of the
world.   Thus we need "satellites" to go "wireless" in Ham Radio.

I am embarassed that my neighbor with his cell phone has far more
capability than I do with Ham radio.  In the past, we LED the way...

de WB4APR, Bob

For more info, see these:

http://www.aprs.org for some APRS info including links to Satellite ideas
http://www.aprs.net and click on a map of your area to see APRS "LIVE"
http://web.usna.navy.mil/~bruninga/mirex.html to see "LIVE" MIR data
TELNET to 199.227.86.221 pt 23 to see the live worldwide APRServe stream
See  Page 19 in January QST for existing APRS Terrestrial Infrastructure



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