[aprssig] How to do a HIKING APRS event!

Bob Bruninga bruninga at usna.edu
Mon May 9 17:52:15 EDT 2011

APRS provided great tracking of the 4 SWEEP hikers and nearly 150 event
runners at the Hike Across Maryland event.  We used 144.39 +600 split
digipeating for a tripling of packet reliability to well above 90% from the
poor 30% or less on previous attempts with normal operations on 144.39
simplex.  You can see a summary of these techniques on the web page:


Unbeknownst to most hams, APRS is easily used to record the positions and
sttus of almost all 150 Hikers during the day too by using text messaging
(from two young hams under 25 who have no fear of texting on a key pad)...

I handed my two kids a TH-D72 APRS radio for their sweep hike duties and
asked them to MESSAGE every hiker # they passed.  My son got to see the
radio the night before, but daughter only got instructions on how to operate
the radio and APRS during her 10 minute breakfast.  TO them, learning the
radio was no big deal.  It was as simple as their cell phones!

After the event, I was amazed! AJ's dozen or so messages reported the TIME,
Location and hiker number of 98 different runners.  My daughter's dozen or
so messages reported about 48 during their few hours on the trail!

THey said it was no big deal,  No different than sending a tweet or an
email.  And remember, that my daughter had only seen a D72 for the 10
minutes while I trained here during breakfast before her hike (never used
APRS before).  She picked it up instantly.  AJ had only seen the radio the
night before but was an expert overnight.

In contrast, I just dont understand why hams have such a complete aversion
to the value of APRS text messaging!  We have hams that have owned their
APRS radios for nearly a decade and do not send or respond to any text
message information.

Looking at the message list in my kids radios AFTER the event when they got
home, there in their radios were the TOTAL 40 or so APRS messages sent by
everyone at the event, containing the time and hiker number reports from

With just an APRS HT anywhere over the 40 miles of maryland, anyone could
just hit the MSG key, scan the messages, and FIND the last report of the
hiker # they were interested in.  There was just no need for us doing voice
to call a station to ASK when did they last see hiker X.  It was all there
in every APRS radio that was ON.

THe reason I didnt see this during the event, was because I was at the
finish line at Harpers Ferry and did not get setup and receiveing anything
until the late afernoon, and by then the messages from these hikers were

Actually, I was very bored there at the end of the trail, because there was
no hiker # info for me to ENTER, since by then the other checkpoints were
closed down and there was no one to see the data. APRS ACTIVITY AT ANY EVENT
IS A *** DATA *** INPUT *** function.  Not a sit and watch event.  If you
think APRS is just for displaying moving GPS units, then you miss the whole
point.   Your APRS job at any event is to ***ENTER*** information so others
can access it!

BOttom line, there is no reason why we cannot report the passing of every
runner at every checkpoint and have it accuulated in EVERY APRS radio at the
event.  Two kids did it who had never even seen an APRS radio before.

With the hiker numbers reported in APRS messages,  Then ANYONE with an APRS
radio can answer the "where is runner XXX" question by just scrolling
through the messages from the last checkpoint and seeing WHEN that runner
passed a point.

We can do this.

Using the 144.39 +600 offset, we had very reliable APRS coverage the entire
route!  BETTER THAN VOICE too.  I could text my son when he was in a
marginal area when voice was not working that well.

The THD72 and maybe the VX8R APRS radios have 100 deep message memories now.
SO capturing every message during the event is possible.  THe older D7 and
D700 radios would only retain the last 16 messages or so, and would only be
able to review only the last hour or so of hiker # reports, but in most
cases, those 16 messages each one containing 10 runner numbers would still
cover the most recent info on the 130 runners who actually finished the

There were LOTS of other lessons learned, but it will take me a while to
write them up.


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