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[aprssig] RE: timeslotting on HF ? was > 15. APRS trackers on 10m (Robert Bruninga)

scott at opentrac.org scott at opentrac.org
Sat Nov 26 20:26:28 UTC 2005


> It seems like some of the chaos we hear on 144.39
> could be avoided by having assigned time slots on 10m

I'd rather see multiple low-rate BPSK channels, and an efficient reporting
protocol.  You could get an ID and full position report out in a few
seconds, with room for FEC.  The OpenTracker's BPSK mode is fixed at a 500
hz carrier, but that could probably be changed to give you at few different
channel options.  A Warbler-style crystal controlled transmitter with a 3
kHz bandwidth ought to work.  And you could reserve a channel for
uncoordinated traffic, too.  I have little faith in 1200 bps FSK on 10
meters.

> hear all the time on 144.39.  Now, exactly how we'd
> get hams to sign up for time slots and stick to them
> is another story, but the reliability increase of

Set up the Igates so they don't gate anyone out-of-cycle on a coordinated
channel.

> hour.  Each slot could be defined by a two byte code,
> and if something like the Pocket Tracker or Open
> Tracker came onboard with firmware prewired to support
> this type of time slotting this could really
> dramatically change how APRS could work on HF.  

The firmware should support it now.  It'd just mean a configuration program
change to translate the 2-byte code into the proper format.

Scott
N1VG







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