[aprssig] A wish for the next TM-D710A firmware update
Rory Burke
rory at burke.ac
Mon May 19 22:02:27 EDT 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
More information about the aprssig
mailing list