[aprssig] A Proposal for the Continuation of APRS

[carcarx at gmail.com]

Something to be wary of regarding "channel sharing":
The Kenwood TM-D710GA, even with the TNC "shut down", will still
digipeat ax.25 packets with a path of TEMPx-y
This is a feature.

When I'm running VARA FM through the 710 with the TNC shut down, eventually
the ax.25 decoder gets sufficiently
"confused" that, once the TNC gets set to APRS mode packet decode degrades
to the point where I need to do
a reset (and a configuration reload) to restore full packet decode.

So having multiple protocols going might not be receiver neutral.
Craig/KH6CP


On Mon, Feb 14, 2022 at 3:07 PM Andrew Pavlin via aprssig <
aprssig at lists.tapr.org> wrote:

> That is assuming both channel-sharing protocols use the same modem tones
> and data link framing (which APRS and OpenTRAC can do). Something like M17
> couldn't share the channel because it uses a different modulation and
> framing scheme, so a Bell 202 tones/HDLC/AX.25 receiver would only
> recognize the M17 signal as interference (and vice versa).
>
> On Monday, February 14, 2022, 07:37:44 PM EST, Scott Miller <
> scott at opentrac.org> wrote:
>
>
> Yes, the receiving device wouldn't even know the protocol until it gets
> the packet and verifies the FCS and checks the protocol ID. Regardless of
> whether the device is using a SQL/COR signal, VOX, or the modem's carrier
> detect it's still going to register as being in use. Some digis might be
> ignoring carrier detect and transmitting over packets, but that's a
> configuration issue.
>
> Scott
> N1VG
>
> On 2/14/2022 4:14 PM, Greg D wrote:
>
> Will stations on the channel that are not dual-mode recognize the "other"
> traffic as "channel occupied", or just transmit over the top and kill the
> packet?  That would be my worry, devolving to Aloha utilization levels or
> worse.
>
> Greg  KO6TH
>
>
> Scott Miller wrote:
>
>
>
> On 2/14/2022 12:55 PM, Andrew Pavlin via aprssig wrote:
>
> You can't practically run both protocols on the same RF channel because it
> wastes channel bandwidth on signals some (single-protocol) stations can't
> understand. We have enough problems with collisions and hidden transmitters
> without making it worse with doubled transmissions from the same stations.
> Plus, there are some digipeaters that can't handle two AX.25 frames
> back-to-back (i.e., one APRS, one OpenTRAC).
>
> I disagree. The added on-air time isn't nearly as bad as a doubling since
> the modem is already locked and everything. Yes, some digipeaters might not
> handle it, but you can put the OpenTRAC packet second if that's not your
> primary protocol and you'll only lose the less important one, and you can
> work on modernizing the network as you go.
>
> Scott
> N1VG
>
>
> _______________________________________________
> aprssig mailing listaprssig at lists.tapr.orghttp://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org
>
>
>
> _______________________________________________
> aprssig mailing listaprssig at lists.tapr.orghttp://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org
>
>
> _______________________________________________
> aprssig mailing list
> aprssig at lists.tapr.org
> http://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org
> _______________________________________________
> aprssig mailing list
> aprssig at lists.tapr.org
> http://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.tapr.org/pipermail/aprssig_lists.tapr.org/attachments/20220214/37e92ecf/attachment.html>