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[aprssig] News from DCC (6) APRS <=> DSTAR universal Voice

Robert Bruninga bruninga at usna.edu
Sat Sep 22 20:56:20 UTC 2012


Given that the APRS integrated radios (kenwood/Yaesu) radios can send
VOICE and DATA simultaneoulsy just like DSTAR we have long wanted an
"ASTAR" gateway that allows any APRS mobile to place (or receive) a
voice call to any other DSTAR radio using only the callsign to set up
the link.  This has been documented on the http://aprs.org/avrs.html
web page.

The goal is to join the APRS community and the DSTAR community with
universal voice connectivity with callsign-to-callsign setup.

This ASTAR gateway is just software on a PC with one foot on the
Internet (Dstar cloud with a DV dongle) but instead of connected to a
speaker and Mic, the audio is remoted to the end APRS user via an
analog TX/RX.  ANd the who-is-calling/who-is-talking is handled with
APRS signaling to/from the front panel of the radio.  Its all there.
Its all possible.  Just need a little software.

The only objection to this concept is the STRONG fear of the DSTAR
community of getting crappy audio into the DSTAR system when the APRS
user has a less than full quieting signal.

This is where YOU come in.  How do we detect in the received audio
from the analog repeater the SIGNAL-TO-NOISE quality so that we know
when the call is of sufficient quality to ALLOW to make a DSTAR call?
Do we use sound card DSP to determine this?  Or do we tap into some
kind of RSSI or SMETER SIGNAL at the voice channel to determine this
threshold?

Remember, this ASTAR node does not really need to use an analog voice
repeater but can just be a SIMPLEX or half duplex pair of RX/TX.  One
simple idea is to use a basestation D700.  The ASTAR node PC can query
the RSSI from the D700 radio the SIGNAL LEVEL of the incoming audio
channel.  THe D700 also can do the full duplex cross band and just
about everything else!??

Let me make a sketch and get it onto the AVRS web page by MOnday.

BoB, WB4APR



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