[aprssig] PIC processor for APRS info for D-STAR mobiles?
Scott Miller
scott at opentrac.org
Tue Jul 8 11:45:10 EDT 2008
I can't help but think that if D-STAR had been designed with some input
from the worldwide amateur community a lot of this could have been built
into the standard.
I don't understand all of the fuss about interleaving other data with a
user's transmission, if there is unused bandwidth there. You could
simply tag it as having originated elsewhere - maybe prefix it with the
repeater's own callsign.
Scott
N1VG
Robert Bruninga wrote:
>>> But if we cannot find a clever way to get access
>>> to the repeater's idle DV bits when it is not in
>>> use, then I can see your issues.
>>
>> There are no "repeater's idle DV bits". A repeater
>> is just that, a repeater. It is repeating someone
>> else's signal and that is how it is presented to all
>> listeners. Hope this helps clear things up.
>
> Thanks. It does. So now then can the following summarise and
> maybe conclude this thread:
>
> 1) D-PRS can translate D-STAR GPS data into APRS for
> distribution on APRS.
> 2) D-PRS can also translate APRS packets into GPS-A format
> 3) There is no inherent displays on D-STAR radios of any of this
> information
> 4) An external display system could be developed to display this
> information
> 5) D-STAR repeaters have no independent DV bit stream inputs.
> 6) The only thing that comes out of a D-STAR repeater is what
> goes in on the RF input.
> 7) Modifying D-STAR repeater functionality is impossible
> 8) Therefore, there is no way to inject local information to the
> repeater DV outgoing bits without sending it in on the RF input
> thereby unacceptibly blocking other voice users.
>
> This of course is what Pete has said all along, but now we have
> seen the basis of the why's and wherefores... The only
> workarounds (no matter how impractical) would require?
>
> 0) Not using a D-STAR repeater, but a bi-directional D-GATE...
> -OR-
>
> 1) Modification of the repeaters for independent streaming of
> the DV bits while the repeater was idle.
>
> 2) Something in those bits to carry a MUTE signal telling the
> user radios that there is no VOICE and to keep the speaker
> quiet.
>
> 3) #2 might require modifications to all participating user
> radios to accept the MUTE?
> 3a) are any of these radios field flashable?
>
> The above (no matter how impractical) would be needed to allow
> the streaming of local information on the DV bits of the
> repeater while the repeater was idle. But when it was in use
> then none of this data is passed. And a voice repeater is
> usually in use for voice... And we cannot interleave other data
> while one person is talking because it would modify his data
> without his permission. So this suggests that we have one more
> requirement:
>
> 4) Add a permission bit in the GPS originated data. Currently
> the D-PRS recommended format is something like "SSS text*CK".
> Maybe the SPACE between the symbol bytes and the text could be
> changed to an underline or something. This signals that this
> user is willing to have his data periodically interleaved with
> other APRS data when he goes through a D-STAR repeater so
> configured..
>
> If Pete can confirm this simplification and/or clean this up,
> then we can let it be the resulting final summary of this thread
> as to the difficulties of supplying local information to the
> D-STAR mobile user via the DV bits.
>
> Maybe?
>
> Bob, WB4APR
>
>
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