[aprssig] APRStt and SAR... Yeesss!

Tom Hayward esarfl at gmail.com
Sun May 17 23:24:46 EDT 2015

On Sun, May 17, 2015 at 5:53 PM, Robert Bruninga via aprssig
<aprssig at tapr.org> wrote:
> Imagine placing this battery powered APRStt engine in a high location at a SAR search.  Then EVERYONE in the SAR event can be tracked and all grids electronically reported.  Either by those with Kenwood and Yaesu APRS radios or by people with nothing but an old IC2AT or a nw Baoefang $40 radio.
> As teams move thorough the SAR area, the ones without APRS radios can simply report their YYYXXX grid location by DTMF followed by their radio's ANI report placing them on the APRS map automatically.

A big assumption you're making is that DTMF is ubiquitous for SAR
teams. In my region, most of the radios that are used on searches do
not have DTMF ability; they are the non-keypad version. Some (like me)
do have a keypad and DTMF on at least one of their radios, but I
wouldn't say this is standard.

> 2) Question.  After an initial report of YYYXXX to place the station on the map, would subsequent YYXX reports be adequate to then update positions and automatically assume the initial most significant bytes Y and X and then keep track and only roll them over when a 9 transitions to a 0 or vice versa?

I would avoid using YYXX, because XXYY has an existing meaning. The
abbreviations truncate digits from the UTM coordinate as they lose
precision, rather dropping the most significant digits.

XXXXXYYYYY - 1m square
XXXXYYYY - 10m square
XXXYYY - 100m square
XXYY - 1km square

I would preserve this standard over the air, so it is more natural for
a searcher to report by punching in DTMF digits. The savings of
airtime is negligible.

> 3) Besides Position, WHAT common messages are reported during a SAR search.  Can we condense it down to just 9 standard situations?  Give me a list of the top ten "status"?
> 0 - off duty
> 1 - enroute (meaing to assigned start point)
> 2 - returning (after search)
> 3 - searching
> 4 - searching with dog team
> 5 - ???
> 6 - ???
> 7 - something found, checking
> 8 - evidence likely
> 9 - send additional assist

Hmm, here are some ideas...
- RTB (returning to base)
- Taking a rest break
- Standing by (waiting for command)

- Instead of "something found, checking", I'd use "heard voice response".
- Instead of "evidence likely", how about "found a clue" and "found
the subject".
This differentiates the status between finding a footprint and finding
the subject.


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