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[aprssig] Hiking with APRS at low risk

Robert Bruninga bruninga at usna.edu
Tue Nov 27 21:13:34 UTC 2007


> I often hike with my D7...
> I would rather have a small battery powered 
> GPS that doesn't need a display...

Not wanting to derail that thread, but an alternative I use on
the Appalachian trail is to simply jot down the coordinates of
some major landmarks every 3 miles or so along my route before I
go.  For a day hike, that's only 6 coordinates or so, and a
posit every hour.

Then I don't bother with the weight of the GPS and batteries,
and cables and wires and broken connectors, and dead batteries,
etc..  I just pull out the HT, manually enter the coordinates,
TX a few times until I am sure it got digipeated.  Turn it off,
and keep walking.  If I am monitroing 2 meters, I turn off the
TNC and APRS band to save power.

Since I carry a map of the trail, I can interpolate or estimate
my posit anywhere in between.  And entering it usually is only a
change in a digit or so.  So I just scroll to the last posit,
bump the knob a few times to my new position, done.

In fact, if I want a more continuous plot, I can easily estimate
my tenths of a minute(LAT/LONG) per 10 minutes walking time and
just increment or decrement my position every 10 minutes easily
enough.  No, it is never precise, but who cares.  It shows my
progress and postion within a tenth of a mile or so all day
long.  It wont help if I fall off a cliff, but then I don't plan
on doing that.  But IF I do need a good posit, then I can unpack
the GPS, get a good fix, and manually enter it.

My whole point is to avoid any cables AT ALL COST.  They will
just snag and usually break a $300 radio or $200 GPS.  It is not
worth the risk to me.  So remember, APRS was designed for MANUAL
updating.  That's why the clients are supposed to DEAD RECKON
all moving objects.  Theoretically all you need to do is enter
your STARTING coordinates, enter a SPEED and DIRECTION toward
your end point for the day, and then turn everything off.

Good APRS clients will then automatically move you along the
display minute by minute all day long.  Each time you update
with a fresh manual posit, then your track is also refreshed.

KISS is my motto (except when I need to show off).. But usually,
I consider showing off a bunch of wires and cables and junk to
be counterproductive and a turn-off.  So I keep it simple and my
track looks pretty good on FINDU...
At least for what I intend it to be.

Just a thought
Bob, WB4APR





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