[aprssig] UTM grid (was: APRStt for SAR using...)

Robert Bruninga bruninga at usna.edu
Thu May 16 19:17:44 EDT 2013

Wow, almost everything you see as a problem, I see as a benefit...

> The problem with this scheme of Bob's is that for it to work, field resources
> still need a GPS ...or... use crude map-based methods to pick off
> coordinates, there is not much value
> to having them type in high-precision UTM coordinates either.

Teams already are fully trained on the UTM grid.  This way you dont
have to teach them APRS, but we are doing the opposite, giving them a
tool that matches their info and procedures.

And we said nothing about high precision.  We said the 3 digit 100m
approximate position info that is currently relayed by voice...

> I would see almost no benefit to asking teams to follow this
> procedure over simply radioing their positions by voice on request, and having
> our comms specialists at base enter the data into APRS in the comfort of the
> incident communications center so it can be shared around the incident
> management team easily.

That is error prone, breaks down under stress, clogs vital comm
channels for simple digital data that can be automatically
displayed... and distracts everyone listening whre more important info
is of interest.

> and where we use APRS we do so to *simplify* information transfer and
> decrease radio chatter, not add complexity to team assignments.

Decreasing radio chatter and the attention of the searchers from
having to monitor the very busy voice channel while trying to
concentrate on their jobs is the goal of allowing DTMF to be used for
this mundane data entry (on another freq) so that the voice channel is
not burdened with this routine numbers that mean nothing except to
those with maps  (APRS)...

> AND it
> is using a technique that is more time consuming and at least as error prone
> as relaying coordinates by voice to a human sitting in front of a better data
> entry system.

 wow, we couldnt disagree more.  That's what wall street said of the

It is far less time consuming to enter 6 digits on a keypad than
having to wait one's turn on a very busy net to then laborously report
the same 6 digits by voice, and wait for confirmation and two way net
control voice procedures to do the same thing.  Im betting it is more
like 4 seconds for DTMF (that bothers no one) and an average 30
seconds or more for a voice report that *everyone* at the event has to
filter through their ears and brain to decide if it is for them or

> I would rather
> see time and energy spent working to get better, lighter, and more reliable
> two-way, automatic APRS devices into searcher's hands.

How long do you want to wait?  Its now been 20 years, TWO decades, and
still only 5% of ham volunteers use APRS.  We need to fully integrate
the other 95% of ham radio operators and let them enter their data (if
appropriate) into APRS via DTMF where it makes sense.  And a 3x3 digit
UTM sar position report seems ideal.


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