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School MIR Experiment



As part of the ongoing APRS School experiment via MIR, and to demonstrate
receipt of messages via a handheld amateur walkie-talkie, the Naval
Academy will be monitoring the MIR downlink on 145.985 using only a
walkie-talkie and its standard rubber duck antenna for the next 4 days.

This test will demonstrate the ability to deliver an emeregency message to
anyone anywhere in the world who only has an HT in their pocket.  The
Kenwood TH-D7 HT will capture any APRS formatted message addressed to its
W3ADO-6 callsign if digipeated via R0MIR.

APRS messages are ONE LINE.  THe format is a UI packet as
follows:

YOURCALL>APRS,R0MIR::W3ADO-6  :This is a test message...

Notice, you can either put the ":W3ADO-6  :message...." in your BText or
you can type it in manually.  Just be sure it is sent to the UNPROTO call
of either BEACON or APRS and that the TOCALL is padded with SPACES to a
total of 9 characters between the colons ":".

The actual text of your message can be no longer than 63 characters after
the colon.  You will NOT get an ack, but if you see the packet digipeated
via MIR, then that is sufficient.  No need to keep transmitting it.  Our
HT will see it too.  I will report results here.

Also, the HT will send its compressed GPS posit once a minute using the
APRS Mic-Encoder format.  (at only 5 watts it will rarely be seen), but if
you see a posit from it, please let me know.  Its posit will look like
this: 

   W3ADO-6>SXUX9U,R0MIR*:`h8wl_K\>Hi!

This contains its position to the nearest 80 feet worldwide, its ICON
which in this case will show on the map as a Kenwood HT, a message saying
"off duty" and then the variable length status text which in this case is
simply "Hi!".  If you are running any flavor of APRS, you will see us on
the map..

For details, see our live MIREX page which captures the last 8 passes of
MIR.  It will also capture and display your packets.  RIght now, MIR is on
and off of Packet while also experimenting with SSTV, but sooner or later,
it will be back to packets...

The HT is simply hidden in a cardboard box on the roof so that no one will
take it, but otherwise it will seem to be a real-world demonstration of an
HT satellite downlink receiver for brief emregeency messages.

de WB4APR, Bob at the US Naval Academy Satellite Lab.


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