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[aprssig] Beacon settings

Keith VE7GDH ve7gdh at rac.ca
Mon Feb 4 18:42:39 UTC 2008


Alan K6PUG wrote...

> I have my Mini-tracker (Icom HT) set for Wide 1-1,Wide2-1
> and my MT1200 in portable mobile (Yaesu) box set for Wide 1-1, 2-2

The recommended setting in North America for mobiles is WIDE1-1,WIDE2-1
for a two hop path. On 144.390 this can take advantage of the existing
infrastructure of WIDEn-N digis and "home fill-in digis" that will
respond to just WIDE1-1. In most places, a three hop path of
WIDE1-1,WIDE2-2 would be excessive. Many digis trap paths longer than
that, either blocking them completely or giving them one hop with no
unused path when it is kicked out the other side.

> On a recent exercise, I was surprised my minitracker wasn't
> digipeated. Jeep guy said "we don't digipeat handhelds."

Who is "Jeep guy" and what is his reasoning for that statement... in
other words (with all due respect) is he ignorant or stupid? How does a
digi know if a particular APRS station is a "handheld" or not? More
importantly, what was the callsign-ssid of the minitracker?

Yes, the best way to get to know your equipment is to use it... day in
and day out, not just when you go out on a task. Find out what works
ahead of time so you and the SAR managers know what to expect instead of
getting "on the job experience" when a real mission is taking place.
Don't assume the batteries in the D7 will be good. Use them regularly so
you know what kind of battery life to expect. Get AA battery packs and
carry spares. Does anyone make a 3rd party Li-PO battery for them? That
would be nice, but (at the expense of some bulk and extra weight) the
users should be able to get AAs just about anywhere.

> Well more recently our Foot group purchased several HTs
> (Kenwood TH-D7 with GPS attached) to assign to foot teams.
> After a couple of years they actually have never been on a
> mission- due to technical challenges for new hams and operational
> issues. I am trying to see them incorporated as a tool (after all
> our non-profit spent $$ buying them).

I hope you get good use out of the D7s. I don't have one, but I
understand they aren't exactly a "tough" radio and won't stand up to a
lot of abuse. I also understand the stock batteries and antennas aren't
particularly good. However, it is an "all in one" APRS station. Add a
GPS receiver and it will automatically update its position. It also has
the advantage of being able to receive APRS messages.

> So I have a unit and am "playing with it. I note the HTs are set
> for RELAY, WIDE. And looking at some paths for known 4WD
> (Aprs query), it appears that the Kenwood mobiles are set for the
> same.

As Steve pointed out, both RELAY and WIDE are obsolete in North America.
RELAY and WIDE were just aliases used in digipeaters. However, there was
no dupe checking and use of them resulted in lots of ping-ponging back
and forth, clogging the frequency. The "new" traceable WIDEn-N avoids
all of the problems that came with RELAY and plain WIDE aliases.

Have you looked at the RTrak from www.rpc-electronics.com? It is a
transmit only device. Down the road, Jason will be developing another
"RTrak" that has a transceiver and a Tracker2 built in instead of just a
transmitter and a regular OpenTracker.

Also, for vehicles you might want to consider the HamHUD II rev E from
www.hamhud.net. It's a lot more intelligent than the D700. The HamHUD V
(video) is still under development.

Another interesting new development is a combination of a Garmin Nuvi
GPS receiver (or other model that has their FMI protocol) and a Tracker2
or a T2-135 in a DR-135T. Scott has discovered that Garmin's "fleet
management interface" can be used to send and receive messages when
connected to a Tracker2 or T2-135. This is an exciting development.
Scott is still working on the code for this, but everything points to it
being very useful and usable.

> Finally I was under the impression that the TH-D7 also could
> digipeat, but was told no.

My understanding is tht the D7 cannot act as a digipeater. However, a
Tracker2 or T2-135 can act as a digipeater. On top of that, it is
capable of pre-emptive digipeating... e.g. you could use a path of e.g.
WIDE1-1,WIDE2-1,SAR7-7 and the rest of the world would ignore the
SAR7-7, but a Tracker2 would be capable of acting on the SARn-N even
though it wasn't the first item in the path. You would be able to take
advantage of the existing infrastructure with the WIDE1-1,WIDE2-1 and
extend the range with your own SARn-N digi, or you could have your
trackers seamlessly move back and forth between the existing 144.390
infrastructure and your own SARn-N digis, whether they were permanent or
temporary during a particular operation. A low priced and very compact
SARn-N digi could be in the form of an Alinco DR-135T with a T2-135
built in. With a GPS receiver connected, it could act as a tracker to
indicate where it was located as well as acting as a portable / mobile
SARn-N digi at the same time. With a compatible Garmin or Magellan GPS
display-type receiver connected, it could also show the position of
other APRS stations around you. With a Nuvi or HamHUD, it would also be
capable of sending and receiving APRS messages.

Keep your eyes on the TinyTrak4 as well. www.byonics.com  The code for
it is still being developed, but the TT4 itself is available now. Allen
KG6HXO who has the Micro-Traks over on the Byonics site also announced
that he will be developing a unit with a transceiver to go along with
the TT4.

> Other than the Bob B's official APRS site, are there any updated pubs
> planned?

You could take at www.nwaprs.info. Also at Stephen's http://wa8lmf.net.
Also www.ui-view.org or www.xastir.org for an APRS client to display the
location of your SAR teams and other information back at the EOC.

73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"





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