You have to admire Bob. No matter what you are doing, from the mundane to exotic, he has found a way for aprs to be an integral part. Maybe he should have been a salesman instead of a teacher...

----- Original Message ----- From: "Nate Duehr" [email protected] To: [email protected]; "'AMSAT-BB'" [email protected] Sent: Wednesday, May 13, 2009 7:55 PM Subject: [amsat-bb] Re: Tracking Friends at Dayton..

On Wed, 13 May 2009 16:43:56 -0400, "Robert Bruninga" [email protected] said:

...

This year you can use your DTMF HT to report where you are hanging out at the Hamvention to about 120 feet just by sending two digits for your XY coordinate.

LOL...

If I were going to be there, I'm going to say via that same HT...

"I'm standing in front of the Brautwurst stand."

Faster than looking myself up on an arbitrary map, punching digits, hoping my friend has the map...

Cool idea, but not sure what problem it's a solution for? I guess if I broke my mic?

Plus, 120' often isn't high enough "resolution". I've stood one stall away from someone in the flea market looking for them before. :-)

Oh well, don't mean to be nitpicky -- have fun at Dayton, all. Even this would be "fun" I guess... I don't know... that's stretching it a bit.

FUN... is finding the repeater or other project parts you need... and knowing you have a way to get them home! (GRIN)

Nate WY0X

Nate Duehr [email protected]

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...

This year you can use your DTMF HT to report where you are hanging out at the Hamvention to about 120 feet just by sending two digits for your XY coordinate.

LOL... If I were going... I'm going to say via that same HT... "I'm standing in front of the Brautwurst stand." Faster than looking myself up on an arbitrary map, punching digits, hoping my friend has the map...

APRS was never intended as an end in itself. It is just another tool in the Ham's toolbox. And it is NOT a tracking system. It was never designed to provide the bandwidth for continuous tracks on everyone or even on ANYone. That is the great missconception about APRS and what burdens the network with unnecessary tracking data when 99% of everyone could care less where 99% of everyone else is.

APRS is a communications system on a single National channel everywhere to facilitate communications between hams needing to communicate without apriori knowledge. There is no reason to transmit your position, unless there is a specific reason why you want someone else to know where you are at that instant. Or to give them in the blind, your call-back frequency.

At Dayton, if you stop for an hour in a forum, or stop for 30 minutes under your club tent, or at the food court or the Bar, then you might want to send out a posit to let your buddies know where you are. In this case there are only four XY coordinates of interest to you. The one at your club tent, the one at the food court, the one at the bar, and the one at the Forums.

Alternatively, someone who wants to know where I am can call my callsign on an agreed frequency.

That works too but requires some inconveniences too.

1) you must have a pre-arranged freq 2) the freq must be relatively clear of other chatter 3) No opportunity for meeting others without #1,#2 4) the recepient must be listeing FULL time 5) Must have his volume turned up 6) Must be paying attention to ALL voice traffic so that he can possibly hear his own call amongst the othres

So both methods have advantages and disadvantages.

An advantage of APRS and APRStt is that the system is global. Once you send out your DTMF callsign memory, anyone in the World of amateur radio that needs to conatact you can not only see you are in dayton (or timbucktu), but can text message you. Again, not that anyone would, but if you ARE expecting someone at a distance to contact you, this gives you the means to be contacted.

For special events like marathons, etc. Just two single digit numbers you may use for your position can be the mile-marks. This lets a VIP shadow, or SAG wagon or any other non-APRS moving asset occasionally report what station it is near (not while moving of couse0, but when he shifs from one station to another. This eliminates a lot of voice traffic from an already overloaded voice net. There are xxyy, xxxyyy and xxxxyyyy higher precision formats available.

Hope that helps. Bob, WB4APR>