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[aprssig] Internet to RF gating of positions

Robert Bruninga bruninga at usna.edu
Tue Sep 2 12:36:00 UTC 2008


>> I had an idea to create a Geocaching gateway
>> - you'd just send a message to CACHE and it 
>> would respond by sending (as stations, in 
>> case objects aren't gated) positions for the 
>> nearest few (non-virtual) caches,

This is a good point.  Maybe we need a whole new APRS format for
"pushing" an object through an Igate.  This is not the first
application that needs this capability.  As the system was
designed, only MESSAGES can go to RF automatically (without
sysop intervention).

I can think of some approaches.  In this case, I will use the
generic term "SERVER" to apply to the device that wants to send
a POSITION of an object to someone he is in message contact....

1) Maybe we can trick the local Igate into sending a "courtesy"
posit.  When USER requests position of OBJECT, SERVER than sends
two packets.  First a POSITION for OBJECT and then a FAKE
message from USER to OBJECT.  Now Igate thinks USER is in
message dialog with OBJECT so it sends "courtesy" report on RF.

Problem is, that a courtesy position is only sent once and then
only once per 30 minutes.  The result is low probability of
reception.

2) Or we just invent a POSITION-in-a-MESSAGE format.  It must be
Human readable so that it can be used now and then new radios
and software can parse it.  I suggest simply what we have now,
the ITEM format...

:USER     :)OBJNAME!DDMM.mmN/DDDMM.mmW$comments....

Bob, WB4APR





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