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

Pete Loveall AE5PL Lists hamlists at ametx.com
Tue Jul 8 10:01:04 EDT 2008


Think of the D-STAR repeater as an FM repeater with a different type of controller.  It is not full duplex, there is nothing to "hack".  The protocol is streaming bits and has some very important safeguards in it to cause such "hacking" that you are talking about to be not only ineffective but potentially illegal in many countries including the US.  What you are asking for is the modification of a signal identified as generated from one station without that station's approval.  Very slippery slope.  This is not packet where data packets "interleaved" on a frequency.  This is streaming bits where only one transmission at a time is allowed.

As for blasting data out on the repeater frequency, do you want this on your local FM repeater using a TNC?  No, because everyone will quit using the repeater.  The same holds true for D-STAR repeater.


Pete Loveall AE5PL
pete at ae5pl dot net

> -----Original Message-----
> From: Robert Bruninga
> Sent: Tuesday, July 08, 2008 8:51 AM
> To: 'TAPR APRS Mailing List'
> Subject: Re: [aprssig] PIC processor for APRS info for D-STAR mobiles?
> A) Ask for (or hack?) a firmware change to the repeater hardware
> so that independent access to the DV output bits and input bits
> are possible.  This would allow the "APRS streamer engine" to
> manipulate what is going out while watching what is coming in.
> IN fact, while one station is talking, and his fix has been
> received and retransmitted, instead of continuing to stream
> those same fix report over and over, then other APRS local area
> fixes could be interleaved.
> B) Without any independent access to the repeater's output DV
> stream, then we accept the impossiblity and go to plan B.  Plan
> B is to add a second DSTAR radio at the repeater site which can
> be configured so that it can transmit when-and-only-when, there
> is not someone on the input.  This radio's DV extra bits are
> used to stream D-PRS translated copies of local APRS Mobiles in
> this area.  This radio does transmit VOICE SILENCE while this is
> taking place.  Though an option for "elevator music" or Rush
> Limbaugh could be made (joke!)...
> C) Do what we can with D-GATE?  It is a processor connected to a
> DV radio, so could it not do the plan B streaming while the full
> repeater was idle?
> Again, I am not saying either of these are practical.  But do
> they answer why the DSTAR users have been saying it is
> impossible.  Or is it only because they assumed the source of
> the D-PRS translanted APRS information was going to get to the
> repeater on the uplink of another D-STAR radio, instead of via a
> backdoor independent input as I was assuming...

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