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[aprssig] Beacon rate/distance (mobile view)

Bob Bruninga bruninga at usna.edu
Mon Oct 12 15:19:48 UTC 2009


I think I can clarify to readers why there are the two schools of thought and both are right within their use of APRS.  Smart beaconing is best for tracking (others watching you on a map) and fixed rate proportional pathing is best for the mobile operator for making real-time APRS contacts with nearby mobiles.

> So your latest complaint about SmartBeaconing 
> is that it doesn't maintain the continuity of
> communications because it doesn't transmit at 
> precise intervals?  You're saying you like 
> fixed-rate beaconing because it's fixed rate?

My comments need to be taken in context and apply to my preferred use of APRS for what it gives to me, the mobile operator while I am driving (not to others who may be watching a map).  The only time I can play radio and APRS is in the mobile and so to me, the optimization of information -to- the mobile operator is my preferred use of APRS.  To some others, being tracked and watched by others might be their goal.

> SmartBeaconing's not regular for a reason: 
> the reporting rate is correlated to the 
> motion, and therefore ROAD-RELATIVE position..

Yes which I agree is great for laying out the best map track histories on maps.  

But when I am mobile, I want to play radio and communicate with other operators and hear what they are doing.  Proportional pathing gives an advantage in that case so that others closeby are updating at a 1 minute rate (direct) while not causing an undue load on the network.  Road relative position accuracy while moving gives little value in this context, since just a few seconds after that report the vehicle is no longer at that spot anyway.  And also, zooming in on a detail GPS map to see a precise postion of where someone was 3 minutes ago gives no useful information for making contact.

> Bob, this is a mere personal preference, 
> not a sound recommendation based in 
> technical fact.  If you have studied the 
> SmartBeaconing algorithm, you know that 
> it, in fact, DOES guarantee a minimum 
> number of position beacons per hour, 
> but ADDS additional beacons to provide 
> information at crucial positional states, 
> like turning a corner.

Yes, and I do want people to understand that I am not denegrating Smart beaconing in any way.  It is a great system for doing what it was designed to do, and that is provide better POSITION-RELATIVE information for providing good track histories.  There are many applications for that in APRS.

Proportional Pathing is not good for that, but was designed for better real-time local communications connectivity between nearby mobiles.

Bob, WB4aPR



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