[aprssig] WiFi for tracking ?

Rich Mulvey aprs at mulveyfamily.com
Mon Aug 13 21:43:18 CDT 2007

Keith VE7GDH wrote:
> Rich (callsign?) wrote...
>> In that vein, I just installed the TomTom 6 navigation software on my
>> mobile phone. It has the extremely cool feature that you can have the
>> GPS navigate you directly to a "buddy" who is also running TT6...
> Just in case you weren't aware, APRS can do exactly that and it isn't
> restricted to the other party having to have a particular mobile phone.
> Think HamHUD, OT1+, Tracker2, T2-135 etc. not to mention those
> that run something like UI-View while mobile on a laptop. There are
> lots of options to allow APRS users to navigate to another APRS user.

   Actually, no, they can't "navigate" in the usual meaning of the 
term.  They can all help you get a bearing to the other station, but 
it's a very cumbersome process to actually get there, especially  if 
you're talking about an urban environment.  I.E., it doesn't help much 
to know that the other station is 6.8 miles from me at 236 degrees when 
there's a maze of buildings, one-way streets, and limited access 
highways between us.  On the other hand, having the GPS automatically 
start rattling off "Turn left in 500 feet..... take second right" *does* 
constitute navigating you to the destination - particularly when the 
target is moving, and the GPS adjusts as necessary. 

>> send them messages, etc. It uses your phone's data connection for all of
>> this, of course.
> That's great as long as your cellular provider isn't having any 
> problems. If
> it's working, use it. On the other hand, APRS users can do the same thing
> without being dependent on the cellular network. The HamHUD can send and
> receive messages. So can D7 and D700 users. Anyone with a T2-135 
> connected
> to a PDA with a terminal program, or a dumb terminal, or a laptop 
> running a
> terminal program can send and receive messages. Anyone that is mobile 
> with
> something like UI-View, Xastir etc. with a radio and TNC connected can 
> also
> send and receive messages.

   Ah, but you've hit the nail right on the head.  I have all of these 
wonderful devices - I have a D700, D7, Tracker 2 beta, and TT3, with 
more GPS's than you can shake a stick at.  The only one that is 
reasonably stand-alone is the D7, and that of course still requires an 
external GPS, cabling, etc.  And yes, I've used it to send messages and 
receive messages - an experience that can best be described as "Slightly 
less painful than an amputation without anesthesia".  ;-)  The T2, OT, 
TT3, HamHud, etc. all of course require a slew of support equipment - 
from a GPS + some sort of terminal device for the first three, to the 
additional TNC for the HamHud.  You'd need some pretty big pockets and 
batteries to manage all of that.  By no stretch of the imagination can 
they be called "portable" in comparison to the rest of what's out there now.

>> For someone like me, who primarily uses APRS as a way
>> of letting family members know where I am when I'm traveling, quite
>> honestly, it blows the socks off of the Amateur APRS infrastructure as
>> it exists today.
> There are lots of different ways of "using" APRS. I'm sure there are many
> people that use it exactly as you do. Just don't get to thinking that a
> one-way tracker is the only way to use APRS. There are other options out
> there, and more showing up all of the time. While the cellular network 
> is in
> many ways "more high tech" than APRS, I think that it is stretching it 
> a bit
> to say that it blows the socks off APRS.
> Cell phones allow anyone that can afford to sign up for a cellular 
> plan with
> the provider of their choice to have a phone in their pocket... and do 
> all
> of the things that you described. APRS is yet another way for amateur 
> radio
> operators to use radio - both in normal times and in extraordinary times
> when everything else around them has fallen apart due to some major
> disaster - to use radio to communicate.Many APRS users carry cell
> phones as well. If both are working, use them. If the cellular network is
> down, hams will be there using radio including APRS to do what can't
> be done when everything else has fallen apart.

    Well, that's the other thing - I've been doing a lot of driving in 
the Eastern US the past year - a region with very high population 
densities.  Even with the D700 at high power, there are *huge* 
stretches, even along major interstates, where there's no APRS 
coverage.  I can listen on 144.390 for extraordinarily long periods of 
time without hearing a single packet.  And yet there's still cell 
coverage even in the some of the deepest, most off-the-beaten-track 
areas of places like West Virginia.  If the measure of "reliability" is 
"the ability to communicate in most of the places you're traveling 
through", then I can't see APRS as meeting that goal.  I ran the only 
IGate in Rochester, NY for about 6 years starting in 1996, and then in 
parallel with K2GXT's for a few more after that.  In the times that the 
power went out, I was the *only* APRS digi/igate up and running.  All of 
the other digis went immediately off the air.  From past discussions on 
the list, that seems to be the norm, rather than the exception.  So if 
it's reliability you want, well...  Heck, I still had internet and cell 
connectivity during the 2003 ice storm here, when the mains were down 
for 8 days.  The only real problem was finding enough gas for the generator.

    So that's basically where I'm coming from - the huge disparity 
between what I see as APRS's stagnation in both hardware and software, 
and the other advances that have been made in portable devices.   It's 
hard to get excited about things like the new D710, for example ( GPS 
connection in the control head?  Who made *that* retarded design 
decision?  Why not a Sirf III chipset that can be purchased wholesale 
for $30? ) in comparison. 

- Rich, AA2YS



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