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[aprssig] APRS and dstar (MotoTrbo)

Stephen H. Smith wa8lmf2 at aol.com
Sun May 27 17:31:58 UTC 2012

On 5/27/2012 12:42 PM, Bob Bruninga wrote:

> I checked out both sites, and both are written for insiders.  There is no explanation as to how an end user with a moto radio communicates with another.  They seem to simply say that all repeaters in the world are linked, so does that mean that every convsersation in the world is sharing the same voice channel and it is impossible to get a word in edgewise?
> Here is what I have always wanted to do since 2001 with ANY RADIO. (DSTAR, MOTOTRBO, or APRS):   I want to talk to W3XYZ no matter where on earth he is.  So I want to enter W3XYZ into my radio and place the call.  If he is avaiable, I want his RADIO to alert him and for him to ANSWER my call.

Anything that stitches these disparate systems together will almost unavoidably 
be an unstable messy software kludge, severely limited by differences in the 
various protocols such as permissible callsign formats, lengths of displayable 
strings, lack or presence of SSIDs, ways of expressing frequencies, ways of 
establishing connections, display formats and resolution, etc.

It may appeal to the hard-core techie types, but the user interface will (most 
likely) be so clunky and vulnerable to entry errors (like the APRS-TT scheme) 
that it will never gain traction with the majority of amateur radio appliance 

[The average user's expectations for user interface ease-of-use has been raised 
to a very high level by Windows, Apple System X, Apple iOS and Android smart 
phones.  There is very little tolerance for anything that smacks of DOS/Linux 
command line interfaces with their requirements for precisely-perfect typing....]

Just look at even the interminable discussions on this list (of mostly the more 
technically-inclined users) about how to get the autotune information properly 
structured to work on all radios.   Or all the endless discussions of how to 
format comments to display on the variety of dissimilar small displays on just 
the various APRS radios.

> Can someone tell me if MotoTrbo can do that?  If so, then yes, a great project then is an MSTAR gateway to AVRS so that I can use my APRS radio to make or receive the call to someone on the MotoTrbo system.

MotoTrbo is just Motorola's catchy marketing name in the US  for the European 
ETSI (Euro Telecommunications Standards Institute) "DMR" (Digital Mobile Radio) 
standard.  This is an open standard with documentation available to anyone.  
Some details here:

. <http://en.wikipedia.org/wiki/Digital_Mobile_Radio>

Note that the basic DMR standard is a two-channel time-division-multiplexed 
system fitted into a normal 25 KHz FM channel.  This yields the equivalent 
spectrum efficiency of 12.5 KHz per voice channel being mandated by the FCC for 
US land mobile beginning next year.



Stephen H. Smith    wa8lmf (at) aol.com
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

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