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[aprssig] A wish for the next TM-D710A firmware update

Rory Burke rory at burke.ac
Tue May 20 02:02:27 UTC 2008


I'd like to see the High Speed parameter for SmartBeaconing increased  
from 70 to something higher - at least 90, and the Fast Rate increased  
to something like 300 seconds.  If you spend some time analyzing the  
SmartBeaconing algorithm you will find that the real beauty of it is  
that you can decided how far apart in distance traveled you want to  
send beacons.  But the High Speed limit defeats that thinking if it is  
lower than the highest speed you travel.  You see, once you reach the  
High Speed, the beacons always come at the Fast Rate.  That means that  
once you are exceeding the High Speed the distance traveled between  
beacons becomes longer and longer.  Here's an example:

Low Speed = 2 mph
High Speed = 60 mph
Slow Rate = 30 minutes
Fast Rate = 60 seconds

You will send a beacon at one mile intervals once you exceed 2 mph  
until you reach 60 mph.  But if you are in one of those places where  
75 mph is safe and legal, you'll be sending beacons at 1-1/4 mile  
intervals.

Now take a look at this example:

Low Speed = 2 mph
High Speed = 90 mph
Slow Rate = 30 minutes
Fast Rate = 40 seconds

In this example you will send a beacon at one mile intervals until you  
reach 90 mph;  a speed that is not normally safe or legal - at least  
in most places in the US.  In this case, you travel 1/8 mile for every  
5 seconds of Fast Rate.  So, if you wanted your beacons 2 miles apart  
you'd select a Fast Rate of 80 seconds, and if you wanted 5 mile  
beacon spacing you'd select a Fast Rate of 200 seconds.  The distance  
traveled between beacons would not change from what you've set unless  
you exceed 90 mph.

I am aware that most folks who use SmartBeaconing are still in the  
"how often am I sending a beacon" mindset rather than the "how far do  
I travel between beacons" mindset.  I believe that if folks would take  
a hard look a the algorithm, and read the SmartBeaconing description  
on the HamHUD web site they would see that the real intent is the "how  
far" mindset.  Please note that the third paragraph of the  
SmartBeaconing description has an error.  It omits the fact that if  
the High Speed threshold is exceeded, then the positions are sent at  
the Fast Rate no matter how much faster you travel.  Here's a link to  
the description:

http://www.hamhud.net/hh2/smartbeacon.html

These changes would take a fairly simple firmware tweak the next time  
there's an update.

73 - Rory - K5MBH

rory at burke.ac     k5mbh at arrl.net

Where am I now?
http://map.findu.com/k5mbh-9





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