[Xastir] Position rate question

[Tom Russo]

On Sat, Jul 07, 2007 at 10:08:46PM -0600, we recorded a bogon-computron collision of the <needhame1 at plateautel.net> flavor, containing:
> 
>  	I've noticed that when I stop I'm getting more positions sent out than I 
>  expected.
> 
>  	Running Xastir 1.9.0 under Kubuntu 7.
> 
>  	I running mobile in an 18-wheeler as KD5XB-11.  SmartBeaconing is enabled, 
>  and set for high speed of 240 MPH with a beacon rate at that speed of once 
>  every 75 seconds.  (I calculate that out to one position report every 5 
>  miles.)  When below the low speed threshold of 2 MPH, I should be getting a 
>  positinb report every 30 minutes.
> 
>  	When I right-click on my own station and get station info, the list of 
>  recent packets received fills up really quickly with 0 MPH reports.  For 
>  instance, I've been sitting here in Shreveport for about 45 minutes, and the 
>  entire list is made up of 0 MPH reports.  I really expected to see only 1 or 
>  2.
> 
>  	So -- is this something I have mis-configured?  A bug?  Or am I 
>  interpreting this list incorrectly?

I, too, have had trouble with the smartbeaconing parameters.  A long
time ago I saw exactly the same behavior you see, and disabled smartbeaconing
at that time.  I've recently re-enabled it on the rare occasions that I 
actually run a laptop in my truck instead of just the D700.  What do you
have your turn threshold, turn slope, and wait time set to?

The default wait time of 5 seconds is absurd, and should not be left there.
Also, Xastir's algorithm for some reason multiplies the turn slope by 10 where
the original HamHud implementation does not.  So you need to use a smaller
turn slope in Xastir than you did in your HamHud.  

Near as I can tell, somehow the random fluctuations of GPS fixes seem to 
allow Xastir to beacon very, very often when stationary if you don't set 
your smartbeaconing just so.  But I never spent any time figuring out why. 
Supposedly the fact that you're at 0mph *should* disable any corner pegging
and only beacon at the slow rate, but as near as I can tell the little hops
that the position fix confuse the issue and make it look like you're *not*
stationary just enough for the code to think you've turned.  But it doesn't
make any sense.  I have found, though, that setting the wait time to 30 seconds
(the most frequently I *ever* want to beacon, no matter how many turns I make)
has decreased the problems I have had with Xastir's smartbeaconing.

-- 
Tom Russo    KM5VY   SAR502   DM64ux          http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236 AHTB#1 http://kevan.org/brain.cgi?DDTNM
"And, isn't sanity really just a one-trick pony anyway? I mean all you get is
 one trick, rational thinking, but when you're good and crazy, oooh, oooh,
 oooh, the sky is the limit!"  --- The Tick