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[aprssig] APRS Local Info Initative TM-D710A compatibitility

Bob Bruninga bruninga at usna.edu
Fri Apr 27 12:49:50 UTC 2012


> I suppose a smart repeater could periodically switch to the 
> APRS frequency and transmit the object if the repeater when not in use...

Maybe I am not following this thread.  But let me clarify.

The APRS Voice Repeater OBJECTS have nothing to do with the Voice Repeater.

The objects are Originated by the local DIGIPEATER as an "on-line" service
to those mobiles in -its- footprint alerting them to what local Voice
Repeater is recommended including its PL for travelers coming into the area.

By SOURCING these objects at the digi every 10 minutes then a Traveler is
never more than 10 minutes from getting this information, yet there is NO
ADDITIONAL LOAD on the network.  THIS IS IMPORTANT.  The digi can hear the
entire 144.39 and ONLY transmit when the channel is clear.  Thus, no
additional load.

If people SOURCE these objects *anywhere else* then it is just one more
beacon, taking up TWO time slices (Doubling the load and douibling the high
probability of colliding with someone else.

Please, everyone understand what FREQ OBJECTS are and how they work.  Also
understand how APRS is completely collision limited by the
"hidden-transmitter" problem.  Only digis can use the channel without
colliding with users.  

We have been pushing this APRSS service for now 8 years as a primary APRS
DIGIPEATER function, and yet less than half of the DIGI SYSOPS have
implemented it.  And because the DIGI owners have not gotten around to it,
then other hams try to source the objects from their home stations using
their 2 Hop paths, and do nothing but DESTROY this concept by adding QRM,
SPAM and useless info that misleads mobiles out of range of the Voice
repeater.

Hope this helps.  

Bob, WB4APR




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