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[aprssig] PIC processor for APRS info for D-STAR mobiles?

Pierre Thibaudeau ve2prt at sympatico.ca
Tue Jul 8 16:17:58 UTC 2008


Today, 11:36 -0400, Robert Bruninga wrote:

>    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

Correction

  - ID-800 and IC91-AD will display positions (latitude and longitude) 
    when they hear GPS messages (only the "original" GPS, not GPS-A).
    Very crude, not very usable, but it's there.

  - IC-2820 and IC-92A will additionally display the distance and bearing 
    of the received position relative to their own (provided it has a 
    local GPS fix). It is limited, but I have found it useful for "last 
    mile approach" when a radio is operated alone (no attached computer).

    Like for the ID-800 and IC91-AD, this capability only applies to GPS 
    messages (not GPS-A). Also, IC-2820 and IC-92A will display GPS 
    informations they hear over the air even when their own setup is to 
    transmit GPS A.

>    4) An external display system could be developed to display this
>    information

There is already such a system. D-PRS (*) provides the required 
translation to make this data readily available to any APRS client. This 
translation is not only available through the repeater to feed APRS-IS 
servers. It can also be done locally, i.e. on a computer connected 
directly to a D-Star radio serial interface.

(*) http://www.aprs-is.net/DPRS.aspx
    http://www.aprs-is.net/images/D-PRS.pdf

>    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.

Although it's not a MUTE signal, speaker remains quiet at the receiving 
end when a D-Star radio sends data. When a radio sends an automatic beacon 
or computer generated data from the serial port (no PTT action) the voice 
part of the signal is pure silence (and occupies the full bandwidth) so 
the receiver end speaker remains totally silent.

'73 - Pierre
__

Pierre Thibaudeau
VA2RKA/VE2RIO/VE2RVR sysadmin




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