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[aprssig] APRS return to basics (DR) (new images)

Keith VE7GDH ve7gdh at rac.ca
Thu May 24 01:35:07 UTC 2012

Randy KA0AZS wrote...

> I'll chime in that I have used DR on several public service events
> over the years as a Net Control and I find it very useful.

I'm sure the will be opinions either way. I'm a UI-View user. It
doesn't do dead reckoning, but it does draw a "vector" line on
the map indicating the direction of travel and relative speed...
at least above speeds of 15 kph. It shows a short lines for slower
speeds, long lines for faster speed. It doesn't actually move the
station based on dead reckoning though.

> Not only for monitoring vehicles with RF trackers, but in placing 
> objects on the board with a course and speed for runners and bike 
> riders without a tracker.  I've used this to give heads ups to turn 
> point and rest stop operators.

UI-View can also create objects. They can either be stationary or
be given a course and speed. If this is done, they actually move on
the map it beacons the new position.

> It's also sometimes easier to ID a station that has a tracker 
> malfunction, when their voice reports show them someplace away
> from where the DR places them.

But is this a function of dead reckoning, or of a station beaconing
a wrong position... e.g. GPS lost a lock and it continued sending
an old position?

> When busy with a (or several) voice frequencies at net control, it's 
> nice to have the computer do the work so I can quickly update my 
> situational awareness while not over tasking my limited wet ware.

If it gives you any more situational awareness, that's great. I was
simply voicing an opinion that I would just rather know the last
known position rather than the client estimating where the station
might be.

> It's also handy to watch storms being plotted by the NWS servers
> and tracking along the screen.

Is DR actually giving you any more information about the storm?
Again, I've never used anything that did dead reckoning. I'm not
trying to pick a fight with you or Bob or anyone else. I'm just
offering an opinion.

Incidentally, what APRS client were you using that did the DR?

73 es cul - Keith VE7GDH
"I may be lost, but I know exactly where I am!" 

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