[aprssig] The ideal APRS digi
John Kraus
jfkraus3 at cox.net
Sun Sep 26 20:02:19 EDT 2004
This could also be a prime use for Digi_Ned. If I am correct Digi_Ned can
receive on multiple ports and cross connect the ports and packets while
doing n-N. It may even be possible to have the packet identified by port on
the output.
Perhaps Henk will add some insight soon.
At 07:52 PM 9/26/2004, you wrote:
>Robert Bruninga wrote on 9/26/2004, 4:18 PM
>
> > To clarify what I am proposing for APRS alt-input digis:
> >
> > The ideal APRS digi should consist of:
> >
> > 1) RX/TX on 144.39 connected to good APRS style TNC
> > 2) RX on alt input channel for locals using any RELAY-only TNC
> > 3) External Carrier Detects cross connected between TNC's
> >
> > See the drawing at: http://www.ew.usna.edu/~bruninga/digi.gif
>
>You might note that this setup has EXACTLY the same
>configuration/integration/DCD issues as adding a Mic-E function to a
>voice repeater; i.e. additional RX on a non-144.39 channel while
>providing TX holdoff until 144.39 is clear.
>
>I have wrestled with this issue for some time now since no
>currently-available dual-port TNCs support 1200 baud on BOTH ports.
>
>One thought I have had about an inexpensive way to implement this would
>to use a TNC-X with the serial RX-data-out line connected directly back
>into the serial TX-data-in line. (Since the TNC-X exclusively uses KISS,
>the retransmission would be an exact duplicate of the transmission
>received. The CD and XCD lines would be cross-connected between the two
>TNCs as in Bob's diagram
>
>Unfortunately, it would also not have the digi's call inserted, or
>WIDEn-N decremented, but it would probably be the cheapest way to go
>(except possibly an old TNC-2 clone with a UI-Digi firmware brain
>transplant). Presumably the digi's primary on-channel TNC beacons would
>statisfy the legal requirements for ID.
>
>
>
>
>Stephen H. Smith wa8lmf (at) aol.com
>
>Home Page: http://wa8lmf.com
>
>
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