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[aprssig] WiFi for tracking ?

Keith VE7GDH ve7gdh at rac.ca
Tue Aug 14 17:04:05 UTC 2007


Rich AA2YS wrote...

> 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...

Well, with a HamHUD, OT1+, Tracker2, T2-135 etc. the received positions
can be sent to the GPS receiver as waypoints. I thought the D700 could do
that as well. All display type GPS receivers allow you to "goto" a waypoint.
Mine (well, just one of mine so far) will give me turn by turn directions...
verbally if I have a speaker connected.

Agreed, if the user is just using UI-View mobile with a non-display GPS
receiver attached, they would have to rely on looking at the map to see
where the other station is currently.

> 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 anaesthesia".  ;-)

I've can only imagine the joy of keying in a message on a D7. The HamHUD has
canned messages, but using the whiz wheel, custom messages can be entered. A
keyboard can be used with the D700 with the interface from John W2FS of
TNC-X fame. Yes, a T2-135 or T2 would require something extra to send and
receive messages... either a dumb terminal, PDA with terminal program or a
laptop with a terminal program.

> 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.

Point taken, but I didn't say that no support equipment was needed. I'll
agree that a D7 with a GPS receiver connected (of course, if you were Bob
WB4APR, you probably wouldn't have the GPS receiver attached - hi!) would
be the most portable unless like Rich (original poster) you had a cell phone
with TomTom 6 in it, but my point was that everything he described could be
done by APRS, and this is an APRS support group, not a cell phone support
group.

> 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'll have to agree with you there. The cellular providers with budgets of
hundreds of millions of dollars (if not billions) can put up more cell sites
than hams who have to pay for the infrastructure out of their own pockets
can do. I'm probably thinking with blinders on. I hardly ever go anywhere,
and anywhere that I would go would have both good APRS and cellular
coverage. Besides, I would have HF with me if I was travelling.

> 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.

There's a lot to be said for having emergency power available. I should be
good for a week if I'm careful, but running the microwave oven, fridge,
freezer, widescreen TV and satellite receiver etc. can cut the run time down
a bit. Maybe I'll add solar panels and/or a wind generator down the road to
supplement the battery bank / inverter and the generator. Some cell sites
have battery backup. Some also have generator backup. Whether battery or
generator, a lot of them probably would only be good for 8-24 hours.

> 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.

I'll agree that hardware like the D7 and D700 have been in stagnation, and
the D710A isn't going to add a whole lot, and the "cast in stone" APRS spec
could be greatly improved by moving to OpenTRAC, but with things like the
T2-135, T2, HamHUD II rev E and the upcoming HamHUD V, the stagnation isn't
complete. While the usual manufacturers offer a pretty good hardware line-up
of HTs, mobile VHF/UHF rigs and both mobile and base HF rigs, the usual
manufacturers can offer a pretty good line-up of equipment, for real
innovation, it looks like individuals and small companies are bringing us
more new toys these days.

> 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.

I don't think I'll be getting a D710A. I can see an argument for having the
GPS connect to the control head, but it is one more cable. Why not use
bluetooth? The GPS receiver would still need power, but it could have a
bluetooth connection to the other end.

I think I made my point that I can do everything with APRS that Rich is
doing with his cell phone, and you made your point that it does take some
additional equipment and that there isn't 144.390 coverage in every nook and
cranny, but this is the APRS support list even though I gave a plug for
OpenTRAC.

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





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